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Luo J, Wang Z, Tang C, Yin Z, Huang J, Ruan D, Fei Y, Wang C, Mo X, Li J, Zhang J, Fang C, Li J, Chen X, Shen W. Animal model for tendinopathy. J Orthop Translat 2023; 42:43-56. [PMID: 37637777 PMCID: PMC10450357 DOI: 10.1016/j.jot.2023.06.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/18/2023] [Accepted: 06/30/2023] [Indexed: 08/29/2023] Open
Abstract
Background Tendinopathy is a common motor system disease that leads to pain and reduced function. Despite its prevalence, our mechanistic understanding is incomplete, leading to limited efficacy of treatment options. Animal models contribute significantly to our understanding of tendinopathy and some therapeutic options. However, the inadequacies of animal models are also evident, largely due to differences in anatomical structure and the complexity of human tendinopathy. Different animal models reproduce different aspects of human tendinopathy and are therefore suitable for different scenarios. This review aims to summarize the existing animal models of tendinopathy and to determine the situations in which each model is appropriate for use, including exploring disease mechanisms and evaluating therapeutic effects. Methods We reviewed relevant literature in the PubMed database from January 2000 to December 2022 using the specific terms ((tendinopathy) OR (tendinitis)) AND (model) AND ((mice) OR (rat) OR (rabbit) OR (lapin) OR (dog) OR (canine) OR (sheep) OR (goat) OR (horse) OR (equine) OR (pig) OR (swine) OR (primate)). This review summarized different methods for establishing animal models of tendinopathy and classified them according to the pathogenesis they simulate. We then discussed the advantages and disadvantages of each model, and based on this, identified the situations in which each model was suitable for application. Results For studies that aim to study the pathophysiology of tendinopathy, naturally occurring models, treadmill models, subacromial impingement models and metabolic models are ideal. They are closest to the natural process of tendinopathy in humans. For studies that aim to evaluate the efficacy of possible treatments, the selection should be made according to the pathogenesis simulated by the modeling method. Existing tendinopathy models can be classified into six types according to the pathogenesis they simulate: extracellular matrix synthesis-decomposition imbalance, inflammation, oxidative stress, metabolic disorder, traumatism and mechanical load. Conclusions The critical factor affecting the translational value of research results is whether the selected model is matched with the research purpose. There is no single optimal model for inducing tendinopathy, and researchers must select the model that is most appropriate for the study they are conducting. The translational potential of this article The critical factor affecting the translational value of research results is whether the animal model used is compatible with the research purpose. This paper provides a rationale and practical guide for the establishment and selection of animal models of tendinopathy, which is helpful to improve the clinical transformation ability of existing models and develop new models.
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Affiliation(s)
- Junchao Luo
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Zetao Wang
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Chenqi Tang
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Binjiang Institute of Zhejiang University, Hangzhou, Zhejiang, China
| | - Zi Yin
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Jiayun Huang
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Dengfeng Ruan
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Yang Fei
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Canlong Wang
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Xianan Mo
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Jiajin Li
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
| | - Jun Zhang
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Department of Orthopedics, Longquan People's Hospital, Zhejiang, 323799, China
| | - Cailian Fang
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
| | - Jianyou Li
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Department of Orthopedics, Huzhou Central Hospital, Affiliated Central Hospital of Huzhou University, Zhejiang University Huzhou Hospital, 313000, Huzhou, Zhejiang, China
| | - Xiao Chen
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Weiliang Shen
- Department of Orthopedic Surgery, The Second Affiliated Hospital of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Orthopedics Research Institute of Zhejiang University, 310058, Hangzhou City, Zhejiang Province, China
- Sports Medicine Institute of Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Clinical Research Center of Motor System Disease of Zhejiang Province, 315825, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, 310058, Hangzhou, Zhejiang, China
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Bloom ET, Lin LM, Locke RC, Giordani A, Krassan E, Peloquin JM, Silbernagel KG, Parreno J, Santare MH, Killian ML, Elliott DM. Overload in a Rat In Vivo Model of Synergist Ablation Induces Tendon Multiscale Structural and Functional Degeneration. J Biomech Eng 2023; 145:081003. [PMID: 37184932 PMCID: PMC10782872 DOI: 10.1115/1.4062523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/16/2023]
Abstract
Tendon degeneration is typically described as an overuse injury with little distinction made between magnitude of load (overload) and number of cycles (overuse). Further, in vivo, animal models of tendon degeneration are mostly overuse models, where tendon damage is caused by a high number of load cycles. As a result, there is a lack of knowledge of how isolated overload leads to degeneration in tendons. A surgical model of synergist ablation (SynAb) overloads the target tendon, plantaris, by ablating its synergist tendon, Achilles. The objective of this study was to evaluate the structural and functional changes that occur following overload of plantaris tendon in a rat SynAb model. Tendon cross-sectional area (CSA) and shape changes were evaluated by longitudinal MR imaging up to 8 weeks postsurgery. Tissue-scale structural changes were evaluated by semiquantified histology and second harmonic generation microscopy. Fibril level changes were evaluated with serial block face scanning electron microscopy (SBF-SEM). Functional changes were evaluated using tension tests at the tissue and microscale using a custom testing system allowing both video and microscopy imaging. At 8 weeks, overloaded plantaris tendons exhibited degenerative changes including increases in CSA, cell density, collagen damage area fraction (DAF), and fibril diameter, and decreases in collagen alignment, modulus, and yield stress. To interpret the differences between overload and overuse in tendon, we introduce a new framework for tendon remodeling and degeneration that differentiates between the inputs of overload and overuse. In summary, isolated overload induces multiscale degenerative structural and functional changes in plantaris tendon.
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Affiliation(s)
- Ellen T Bloom
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716
| | - Lily M Lin
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716
| | - Ryan C Locke
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104; Translational Musculoskeletal Research Center, CMCVAMC, Philadelphia, PA 19104
| | - Alyssa Giordani
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716
| | - Erin Krassan
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716
| | - John M Peloquin
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716
| | | | - Justin Parreno
- Department of Biological Sciences, University of Delaware, Newark, DE 19716
| | - Michael H Santare
- Department of Mechanical Engineering, University of Delaware, Newark, DE 19716
| | - Megan L Killian
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48104
| | - Dawn M Elliott
- Department of Biomedical Engineering, University of Delaware, Newark, DE 19716
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Holt NC, Mayfield DL. Muscle-tendon unit design and tuning for power enhancement, power attenuation, and reduction of metabolic cost. J Biomech 2023; 153:111585. [PMID: 37126884 PMCID: PMC10949972 DOI: 10.1016/j.jbiomech.2023.111585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 05/03/2023]
Abstract
The contractile elements in skeletal muscle fibers operate in series with elastic elements, tendons and potentially aponeuroses, in muscle-tendon units (MTUs). Elastic strain energy (ESE), arising from either work done by muscle fibers or the energy of the body, can be stored in these series elastic elements (SEEs). MTUs vary considerably in their design in terms of the relative lengths and stiffnesses of the muscle fibers and SEEs, and the force and work generating capacities of the muscle fibers. However, within an MTU it is thought that contractile and series elastic elements can be matched or tuned to maximize ESE storage. The use of ESE is thought to improve locomotor performance by enhancing contractile element power during activities such as jumping, attenuating contractile element power during activities such as landing, and reducing the metabolic cost of movement during steady-state activities such as walking and running. The effectiveness of MTUs in these potential roles is contingent on factors such as the source of mechanical energy, the control of the flow of energy, and characteristics of SEE recoil. Hence, we suggest that MTUs specialized for ESE storage may vary considerably in the structural, mechanical, and physiological properties of their components depending on their functional role and required versatility.
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Affiliation(s)
- N C Holt
- Department of Evolution, Ecology and Organismal Biology, University of California Riverside, 900 University Avenue, Riverside, CA 92521, USA.
| | - D L Mayfield
- Department of Evolution, Ecology and Organismal Biology, University of California Riverside, 900 University Avenue, Riverside, CA 92521, USA
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4
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Lyu SY, Xiao W, Cui GZ, Yu C, Liu H, Lyu M, Kuang QY, Xiao EH, Luo YH. Role and mechanism of DNA methylation and its inhibitors in hepatic fibrosis. Front Genet 2023; 14:1124330. [PMID: 37056286 PMCID: PMC10086238 DOI: 10.3389/fgene.2023.1124330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
Liver fibrosis is a repair response to injury caused by various chronic stimuli that continually act on the liver. Among them, the activation of hepatic stellate cells (HSCs) and their transformation into a myofibroblast phenotype is a key event leading to liver fibrosis, however the mechanism has not yet been elucidated. The molecular basis of HSC activation involves changes in the regulation of gene expression without changes in the genome sequence, namely, via epigenetic regulation. DNA methylation is a key focus of epigenetic research, as it affects the expression of fibrosis-related, metabolism-related, and tumor suppressor genes. Increasing studies have shown that DNA methylation is closely related to several physiological and pathological processes including HSC activation and liver fibrosis. This review aimed to discuss the mechanism of DNA methylation in the pathogenesis of liver fibrosis, explore DNA methylation inhibitors as potential therapies for liver fibrosis, and provide new insights on the prevention and clinical treatment of liver fibrosis.
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Affiliation(s)
- Shi-Yi Lyu
- Department of Radiology, The Second Xiangya Hospital, Central-South University, Changsha, Hunan, China
| | - Wang Xiao
- Department of Gastrointestinal Surgery, The Second Xiangya Hospital, Central-South University, Changsha, Hunan, China
| | - Guang-Zu Cui
- XiangYa School of Medicine, Central South University, Changsha, Hunan, China
| | - Cheng Yu
- Department of Radiology, The Second Xiangya Hospital, Central-South University, Changsha, Hunan, China
| | - Huan Liu
- Department of Radiology, The Second Xiangya Hospital, Central-South University, Changsha, Hunan, China
| | - Min Lyu
- Department of Radiology, The Second Xiangya Hospital, Central-South University, Changsha, Hunan, China
| | - Qian-Ya Kuang
- Department of Radiology, The Second Xiangya Hospital, Central-South University, Changsha, Hunan, China
| | - En-Hua Xiao
- Department of Radiology, The Second Xiangya Hospital, Central-South University, Changsha, Hunan, China
| | - Yong-Heng Luo
- Department of Radiology, The Second Xiangya Hospital, Central-South University, Changsha, Hunan, China
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5
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Gains CC, Giannapoulos A, Zamboulis DE, Lopez-Tremoleda J, Screen HRC. Development and application of a novel in vivo overload model of the Achilles tendon in rat. J Biomech 2023; 151:111546. [PMID: 36958089 DOI: 10.1016/j.jbiomech.2023.111546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 03/03/2023] [Accepted: 03/09/2023] [Indexed: 03/17/2023]
Abstract
Repetitive overload is a primary factor in tendon injury, causing progressive accumulation of matrix damage concurrent with a cellular response. However, it remains unclear how these events occur at the initial stages of the disease, making it difficult to identify appropriate treatment approaches. Here, we describe the development of a new model to cyclically load the Achilles tendon (AT) of rats in vivo and investigate the initial structural and cellular responses. The model utilizes controlled dorsiflexion of the ankle joint applied near maximal dorsiflexion, for 10,000 cycles at 3 Hz. Animals were subjected to a single bout of in vivo loading under anaesthesia, and either culled immediately (without recovery from anaesthesia), or 48 h or 4-weeks post-loading. Macro strains were assessed in cadavers, whilst tendon specific microdamage was assessed through collagen-hybridizing peptide (CHP) immunohistochemistry which highlighted a significant rise in CHP staining in loaded ATs compared to contralateral controls, indicating an accumulation of overload-induced damage. Staining for pro-inflammatory mediators (IL-6 and COX-2) and matrix degradation markers (MMP-3 and -13) also suggests an initial cellular response to overload. Model validation confirmed our approach was able to explore early overload-induced damage within the AT, with microdamage present and no evidence of broader musculoskeletal damage. The new model may be implemented to map the progression of tendinopathy in the AT, and thus study potential therapeutic interventions.
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Affiliation(s)
- Connor Charles Gains
- School of Engineering and Materials Science (SEMS), Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom.
| | - Antonios Giannapoulos
- School of Engineering and Materials Science (SEMS), Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Danae Emilie Zamboulis
- School of Engineering and Materials Science (SEMS), Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Jordi Lopez-Tremoleda
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Hazel R C Screen
- School of Engineering and Materials Science (SEMS), Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
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Crossland H, Brook MS, Quinlan JI, Franchi MV, Phillips BE, Wilkinson DJ, Maganaris CN, Greenhaff PL, Szewczyk NJ, Smith K, Narici MV, Atherton PJ. Metabolic and molecular responses of human patellar tendon to concentric- and eccentric-type exercise in youth and older age. GeroScience 2022; 45:331-344. [PMID: 35948859 PMCID: PMC9886711 DOI: 10.1007/s11357-022-00636-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 07/28/2022] [Indexed: 02/03/2023] Open
Abstract
Exercise training can induce adaptive changes to tendon tissue both structurally and mechanically; however, the underlying compositional changes that contribute to these alterations remain uncertain in humans, particularly in the context of the ageing tendon. The aims of the present study were to determine the molecular changes with ageing in patellar tendons in humans, as well as the responses to exercise and exercise type (eccentric (ECC) and concentric (CON)) in young and old patellar tendon. Healthy younger males (age 23.5 ± 6.1 years; n = 27) and older males (age 68.5 ± 1.9 years; n = 27) undertook 8 weeks of CON or ECC training (3 times per week; at 60% of 1 repetition maximum (1RM)) or no training. Subjects consumed D2O throughout the protocol and tendon biopsies were collected after 4 and 8 weeks for measurement of fractional synthetic rates (FSR) of tendon protein synthesis and gene expression. There were increases in tendon protein synthesis following 4 weeks of CON and ECC training (P < 0.01; main effect by ANOVA), with no differences observed between young and old males, or training type. At the transcriptional level however, ECC in young adults generally induced greater responses of collagen and extracellular matrix-related genes than CON, while older individuals had reduced gene expression responses to training. Different training types did not appear to induce differential tendon responses in terms of protein synthesis, and while tendons from older adults exhibited different transcriptional responses to younger individuals, protein turnover changes with training were similar for both age groups.
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Affiliation(s)
- Hannah Crossland
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
| | - Matthew S Brook
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
| | - Jonathan I Quinlan
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
- 3National Institute for Health Research, Birmingham Biomedical Research Centre at University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Martino V Franchi
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Bethan E Phillips
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
| | - Daniel J Wilkinson
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
| | | | - Paul L Greenhaff
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
| | - Nathaniel J Szewczyk
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
- Ohio Musculoskeletal and Neurological Institute (OMNI) and Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA
| | - Kenneth Smith
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
| | - Marco V Narici
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK
- Department of Biomedical Sciences, University of Padova, Padua, Italy
- CIR-MYO Myology Center, University of Padova, Padua, Italy
| | - Philip J Atherton
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre, Derby, DE22 3DT, UK.
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7
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Shear-stress sensing by PIEZO1 regulates tendon stiffness in rodents and influences jumping performance in humans. Nat Biomed Eng 2021; 5:1457-1471. [PMID: 34031557 PMCID: PMC7612848 DOI: 10.1038/s41551-021-00716-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 03/17/2021] [Indexed: 01/31/2023]
Abstract
Athletic performance relies on tendons, which enable movement by transferring forces from muscles to the skeleton. Yet, how load-bearing structures in tendons sense and adapt to physical demands is not understood. Here, by performing calcium (Ca2+) imaging in mechanically loaded tendon explants from rats and in primary tendon cells from rats and humans, we show that tenocytes detect mechanical forces through the mechanosensitive ion channel PIEZO1, which senses shear stresses induced by collagen-fibre sliding. Through tenocyte-targeted loss-of-function and gain-of-function experiments in rodents, we show that reduced PIEZO1 activity decreased tendon stiffness and that elevated PIEZO1 mechanosignalling increased tendon stiffness and strength, seemingly through upregulated collagen cross-linking. We also show that humans carrying the PIEZO1 E756del gain-of-function mutation display a 13.2% average increase in normalized jumping height, presumably due to a higher rate of force generation or to the release of a larger amount of stored elastic energy. Further understanding of the PIEZO1-mediated mechanoregulation of tendon stiffness should aid research on musculoskeletal medicine and on sports performance.
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Williamson PM, Freedman BR, Kwok N, Beeram I, Pennings J, Johnson J, Hamparian D, Cohen E, Galloway JL, Ramappa AJ, DeAngelis JP, Nazarian A. Tendinopathy and tendon material response to load: What we can learn from small animal studies. Acta Biomater 2021; 134:43-56. [PMID: 34325074 DOI: 10.1016/j.actbio.2021.07.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 07/16/2021] [Accepted: 07/21/2021] [Indexed: 12/20/2022]
Abstract
Tendinopathy is a debilitating disease that causes as much as 30% of all musculoskeletal consultations. Existing treatments for tendinopathy have variable efficacy, possibly due to incomplete characterization of the underlying pathophysiology. Mechanical load can have both beneficial and detrimental effects on tendon, as the overall tendon response depends on the degree, frequency, timing, and magnitude of the load. The clinical continuum model of tendinopathy offers insight into the late stages of tendinopathy, but it does not capture the subclinical tendinopathic changes that begin before pain or loss of function. Small animal models that use high tendon loading to mimic human tendinopathy may be able to fill this knowledge gap. The goal of this review is to summarize the insights from in-vivo animal studies of mechanically-induced tendinopathy and higher loading regimens into the mechanical, microstructural, and biological features that help characterize the continuum between normal tendon and tendinopathy. STATEMENT OF SIGNIFICANCE: This review summarizes the insights gained from in-vivo animal studies of mechanically-induced tendinopathy by evaluating the effect high loading regimens have on the mechanical, structural, and biological features of tendinopathy. A better understanding of the interplay between these realms could lead to improved patient management, especially in the presence of painful tendon.
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9
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Quantifying supraspinatus tendon responses to exposures emulative of human physiological levels in an animal model. J Biomech 2021; 122:110476. [PMID: 33933860 DOI: 10.1016/j.jbiomech.2021.110476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/21/2021] [Accepted: 04/19/2021] [Indexed: 11/21/2022]
Abstract
Rotator cuff pathology typically originates in the supraspinatus tendon, but uncertainty exists on how combinations of glenohumeral elevation angle and load intensity influence responses of the intact, functional supraspinatus unit. This study exposed the supraspinatus tendon to mechanical loading scenarios emulative of derived muscle force and postural conditions measured in vivo to document its responses. Right shoulders from 48 Sprague-Dawley rats were placed into one of eight testing groups combining glenohumeral elevation angles (0/30/60/75°) and a high or low load intensity for 1500 cycles at 0.25 Hz using a custom mounting apparatus attached to a tensile testing system. Load intensities were derived from in vivo human partitional muscular activation levels collected previously and scaled to the animal model. Mechanical response variables examined included tangent stiffness and hysteresis, in addition to localized surface stretch ratios calculated via virtual tracking points. A significant three-way interaction (p = 0.0009) between elevation angle, load magnitude and cycle number occurred for tangent stiffness, with increasing angles, loads and cycles increasing stiffness by up to 49%. Longitudinal stretch ratios had significant interactions (p = 0.0396) with increasing elevation angles, load intensities and cycle numbers, and differences existed between the articular and bursal sides of the tendon. Complex interactions between angle, load and cycle number suggest higher abduction angles, increased load magnitude and higher loading cycles increase tangent stiffness, stretch ratios and hysteresis within the tendon.
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10
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Nuss CA, Huegel J, Finkielsztein S, Soslowsky LJ. Liquid Poly-N-acetyl Glucosamine (sNAG) Improves Achilles Tendon Healing in a Rat Model. Ann Biomed Eng 2021; 49:515-522. [PMID: 33409852 PMCID: PMC8178587 DOI: 10.1007/s10439-020-02711-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/14/2020] [Indexed: 11/25/2022]
Abstract
The Achilles tendon, while the strongest and largest tendon in the body, is frequently injured. Even after surgical repair, patients risk re-rupture and long-term deficits in function. Poly-N-acetyl glucosamine (sNAG) polymer has been shown to increase the rate of healing of venous leg ulcers, and use of this material improved tendon-to-bone healing in a rat model of rotator cuff injury. Therefore, the purpose of this study was to investigate the healing properties of liquid sNAG polymer suspension in a rat partial Achilles tear model. We hypothesized that repeated sNAG injections throughout healing would improve Achilles tendon healing as measured by improved mechanical properties and cellular morphology compared to controls. Results demonstrate that sNAG has a positive effect on rat Achilles tendon healing at three weeks after a full thickness, partial width injury. sNAG treatment led to increased quasistatic tendon stiffness, and increased tangent and secant stiffness throughout fatigue cycling protocols. Increased dynamic modulus also suggests improved viscoelastic properties with sNAG treatment. No differences were identified in histological properties. Importantly, use of this material did not have any negative effects on any measured parameter. These results support further study of this material as a minimally invasive treatment modality for tendon healing.
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Affiliation(s)
- Courtney A Nuss
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 371 Stemmler Hall, Philadelphia, PA, 19104-6081, USA
| | - Julianne Huegel
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 371 Stemmler Hall, Philadelphia, PA, 19104-6081, USA
| | - Sergio Finkielsztein
- Marine Polymer Technologies, Inc., 1 Van De Graaff Drive, Suite 302, Burlington, MA, 01803, USA
| | - Louis J Soslowsky
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, 3450 Hamilton Walk, 371 Stemmler Hall, Philadelphia, PA, 19104-6081, USA.
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11
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Siadat SM, Zamboulis DE, Thorpe CT, Ruberti JW, Connizzo BK. Tendon Extracellular Matrix Assembly, Maintenance and Dysregulation Throughout Life. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1348:45-103. [PMID: 34807415 DOI: 10.1007/978-3-030-80614-9_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
In his Lissner Award medal lecture in 2000, Stephen Cowin asked the question: "How is a tissue built?" It is not a new question, but it remains as relevant today as it did when it was asked 20 years ago. In fact, research on the organization and development of tissue structure has been a primary focus of tendon and ligament research for over two centuries. The tendon extracellular matrix (ECM) is critical to overall tissue function; it gives the tissue its unique mechanical properties, exhibiting complex non-linear responses, viscoelasticity and flow mechanisms, excellent energy storage and fatigue resistance. This matrix also creates a unique microenvironment for resident cells, allowing cells to maintain their phenotype and translate mechanical and chemical signals into biological responses. Importantly, this architecture is constantly remodeled by local cell populations in response to changing biochemical (systemic and local disease or injury) and mechanical (exercise, disuse, and overuse) stimuli. Here, we review the current understanding of matrix remodeling throughout life, focusing on formation and assembly during the postnatal period, maintenance and homeostasis during adulthood, and changes to homeostasis in natural aging. We also discuss advances in model systems and novel tools for studying collagen and non-collagenous matrix remodeling throughout life, and finally conclude by identifying key questions that have yet to be answered.
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Affiliation(s)
| | - Danae E Zamboulis
- Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Chavaunne T Thorpe
- Comparative Biomedical Sciences, The Royal Veterinary College, University of London, London, UK
| | - Jeffrey W Ruberti
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Brianne K Connizzo
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
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12
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Chen M, Shetye SS, Rooney SI, Soslowsky LJ. Short- and Long-Term Exercise Results in a Differential Achilles Tendon Mechanical Response. J Biomech Eng 2020; 142:081011. [PMID: 32253439 PMCID: PMC7477707 DOI: 10.1115/1.4046864] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/22/2020] [Indexed: 12/28/2022]
Abstract
The study was conducted to define the biomechanical response of rat Achilles tendon after a single bout of exercise and a short or long duration of daily exercise. We hypothesized that a single bout or a short duration of exercise would cause a transient decrease in Achilles tendon mechanical properties and a long duration of daily exercise would improve these properties. One hundred and thirty-six Sprague-Dawley rats were divided into cage activity (CA) or exercise (EX) groups for a single bout, short-term, or long-term exercise. Animals in single bout EX groups were euthanized, 3, 12, 24, or 48 h upon completion of a single bout of exercise (10 m/min, 1 h) on a flat treadmill. Animals in short-term EX groups ran on a flat treadmill for 3 days, 1, or 2 weeks while animals in long-term EX groups ran for 8 weeks. Tendon quasi-static and viscoelastic response was evaluated for all Achilles tendons. A single bout of exercise increased tendon stiffness after 48 h of recovery. Short-term exercise up to 1 week decreased cross-sectional area, stiffness, modulus, and dynamic modulus of the Achilles tendon. In contrast, 8 weeks of daily exercise increased stiffness, modulus, and dynamic modulus of the tendon. This study highlights the response of Achilles tendons to single and sustained bouts of exercise. Adequate time intervals are important to allow for tendon adaptations when initiating a new training regimen and overall beneficial effects to the Achilles tendon.
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Affiliation(s)
- Mengcun Chen
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104; Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Snehal S. Shetye
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Louis J. Soslowsky
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, G13A Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6081
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13
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Williams M, Sater S, Burkhalter C, Schoonen S, Miller J, Shrestha D, Brumley MR, Schiele NR. Low-cost, open-source, variable speed and incline treadmill for studying impacts of neonatal locomotion. HARDWAREX 2020; 7:e00097. [PMID: 35495209 PMCID: PMC9041207 DOI: 10.1016/j.ohx.2020.e00097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 12/23/2019] [Accepted: 01/07/2020] [Indexed: 06/14/2023]
Abstract
There is a need for a small-scale, laboratory treadmill to investigate impacts of neonatal locomotion on neuromuscular and musculoskeletal development in small animal models. Adult mice and rats are routinely assessed using commercially available treadmills, but these treadmills can be relatively expensive and they may lack features needed to evaluate developing animals. Therefore, to overcome these limitations, a new treadmill was designed, built and calibrated. This open-source treadmill was designed specifically for neonatal and postnatal mice and rats, and it fits within a neonatal incubator. By using predominantly off-the-shelf and 3D printed components, and a microcontroller, this treadmill was low cost and easy to reproduce. The design also included variable incline, and a transparent belt and enclosures for video and gait analysis. A touchscreen interface provided user-friendly control over belt speed and run time. Moreover, validation experiments showed high accuracy in belt speed control, allowing for tightly regulated experimental conditions. Overall, this new low-cost, open-source, variable speed and incline treadmill can be used to advance understanding of neonatal locomotion, and neuromuscular and musculoskeletal development.
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Affiliation(s)
- Mitchell Williams
- University of Idaho, Department of Mechanical Engineering, Moscow, ID, United States
| | - Stuart Sater
- University of Idaho, Department of Biological Engineering, Moscow, ID, United States
| | - Colin Burkhalter
- University of Idaho, Department of Mechanical Engineering, Moscow, ID, United States
| | - Stephen Schoonen
- University of Idaho, Department of Biological Engineering, Moscow, ID, United States
| | - Jacob Miller
- University of Idaho, Department of Mechanical Engineering, Moscow, ID, United States
| | - Dev Shrestha
- University of Idaho, Department of Biological Engineering, Moscow, ID, United States
| | - Michele R. Brumley
- Idaho State University, Department of Psychology, Pocatello, ID, United States
| | - Nathan R. Schiele
- University of Idaho, Department of Biological Engineering, Moscow, ID, United States
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14
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In Vivo and In Vitro Mechanical Loading of Mouse Achilles Tendons and Tenocytes-A Pilot Study. Int J Mol Sci 2020; 21:ijms21041313. [PMID: 32075290 PMCID: PMC7072865 DOI: 10.3390/ijms21041313] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/05/2020] [Accepted: 02/10/2020] [Indexed: 12/21/2022] Open
Abstract
Mechanical force is a key factor for the maintenance, adaptation, and function of tendons. Investigating the impact of mechanical loading in tenocytes and tendons might provide important information on in vivo tendon mechanobiology. Therefore, the study aimed at understanding if an in vitro loading set up of tenocytes leads to similar regulations of cell shape and gene expression, as loading of the Achilles tendon in an in vivo mouse model. In vivo: The left tibiae of mice (n = 12) were subject to axial cyclic compressive loading for 3 weeks, and the Achilles tendons were harvested. The right tibiae served as the internal non-loaded control. In vitro: tenocytes were isolated from mice Achilles tendons and were loaded for 4 h or 5 days (n = 6 per group) based on the in vivo protocol. Histology showed significant differences in the cell shape between in vivo and in vitro loading. On the molecular level, quantitative real-time PCR revealed significant differences in the gene expression of collagen type I and III and of the matrix metalloproteinases (MMP). Tendon-associated markers showed a similar expression profile. This study showed that the gene expression of tendon markers was similar, whereas significant changes in the expression of extracellular matrix (ECM) related genes were detected between in vivo and in vitro loading. This first pilot study is important for understanding to which extent in vitro stimulation set-ups of tenocytes can mimic in vivo characteristics.
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15
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Connizzo BK, Piet JM, Shefelbine SJ, Grodzinsky AJ. Age-associated changes in the response of tendon explants to stress deprivation is sex-dependent. Connect Tissue Res 2020; 61:48-62. [PMID: 31411079 PMCID: PMC6884684 DOI: 10.1080/03008207.2019.1648444] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purpose of the Study: The incidence of tendon injuries increases dramatically with age, which presents a major clinical burden. While previous studies have sought to identify age-related changes in extracellular matrix structure and function, few have been able to explain fully why aged tissues are more prone to degeneration and injury. In addition, recent studies have also demonstrated that age-related processes in humans may be sex-dependent, which could be responsible for muddled conclusions in changes with age. In this study, we investigate short-term responses through an ex vivo explant culture model of stress deprivation that specifically questions how age and sex differentially affect the ability of tendons to respond to altered mechanical stimulus.Materials and Methods: We subjected murine flexor explants from young (4 months of age) and aged (22-24 months of age) male and female mice to stress-deprived culture conditions for up to 1 week and investigated changes in viability, cell metabolism and proliferation, matrix biosynthesis and composition, gene expression, and inflammatory responses throughout the culture period.Results and Conclusions: We found that aging did have a significant influence on the response to stress deprivation, demonstrating that aged explants have a less robust response overall with reduced metabolic activity, viability, proliferation, and biosynthesis. However, age-related changes appeared to be sex-dependent. Together, this work demonstrates that the aging process and the subsequent effect of age on the ability of tendons to respond to stress-deprivation are inherently different based on sex, where male explants favor increased activity, apoptosis, and matrix remodeling while female explants favor reduced activity and tissue preservation.
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Affiliation(s)
- Brianne K. Connizzo
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Correspondence: Brianne K. Connizzo, 70 Massachusetts Avenue, NE47-377, Cambridge, MA 02139, T: 617-253-2469,
| | - Judith M. Piet
- Department of Bioengineering, Northeastern University, Boston, MA 02115, United States
| | - Sandra J. Shefelbine
- Department of Bioengineering, Northeastern University, Boston, MA 02115, United States,Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115, United States
| | - Alan J. Grodzinsky
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Center for Biomedical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
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16
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Abstract
Tendons link muscle to bone and transfer forces necessary for normal movement. Tendon injuries can be debilitating and their intrinsic healing potential is limited. These challenges have motivated the development of model systems to study the factors that regulate tendon formation and tendon injury. Recent advances in understanding of embryonic and postnatal tendon formation have inspired approaches that aimed to mimic key aspects of tendon development. Model systems have also been developed to explore factors that regulate tendon injury and healing. We highlight current model systems that explore developmentally inspired cellular, mechanical, and biochemical factors in tendon formation and tenogenic stem cell differentiation. Next, we discuss in vivo, in vitro, ex vivo, and computational models of tendon injury that examine how mechanical loading and biochemical factors contribute to tendon pathologies and healing. These tendon development and injury models show promise for identifying the factors guiding tendon formation and tendon pathologies, and will ultimately improve regenerative tissue engineering strategies and clinical outcomes.
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Affiliation(s)
- Sophia K Theodossiou
- Biological Engineering, University of Idaho, 875 Perimeter Dr. MS 0904, Moscow, ID 83844, USA
| | - Nathan R Schiele
- Biological Engineering, University of Idaho, 875 Perimeter Dr. MS 0904, Moscow, ID 83844, USA
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17
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Zhang C, Zhu J, Zhou Y, Thampatty BP, Wang JHC. Tendon Stem/Progenitor Cells and Their Interactions with Extracellular Matrix and Mechanical Loading. Stem Cells Int 2019; 2019:3674647. [PMID: 31737075 PMCID: PMC6815631 DOI: 10.1155/2019/3674647] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/04/2019] [Accepted: 08/17/2019] [Indexed: 12/11/2022] Open
Abstract
Tendons are unique connective tissues in the sense that their biological properties are largely determined by their tendon-specific stem cells, extracellular matrix (ECM) surrounding the stem cells, mechanical loading conditions placed on the tendon, and the complex interactions among them. This review is aimed at providing an overview of recent advances in the identification and characterization of tendon stem/progenitor cells (TSPCs) and their interactions with ECM and mechanical loading. In addition, the effects of such interactions on the maintenance of tendon homeostasis and the initiation of tendon pathological conditions are discussed. Moreover, the challenges in further investigations of TSPC mechanobiology in vitro and in vivo are outlined. Finally, future research efforts are suggested, which include using specific gene knockout models and single-cell transcription profiling to enable a broad and deep understanding of the physiology and pathophysiology of tendons.
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Affiliation(s)
- Chuanxin Zhang
- Joint Surgery and Sports Medicine Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Jun Zhu
- Joint Surgery and Sports Medicine Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Yiqin Zhou
- Joint Surgery and Sports Medicine Department, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Bhavani P. Thampatty
- MechanoBiology Laboratory, Departments of Orthopaedic Surgery, Bioengineering, and Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - James H-C. Wang
- MechanoBiology Laboratory, Departments of Orthopaedic Surgery, Bioengineering, and Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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18
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Onset of neonatal locomotor behavior and the mechanical development of Achilles and tail tendons. J Biomech 2019; 96:109354. [PMID: 31630773 DOI: 10.1016/j.jbiomech.2019.109354] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/21/2019] [Accepted: 09/18/2019] [Indexed: 12/27/2022]
Abstract
Tendon tissue engineering approaches are challenged by a limited understanding of the role mechanical loading plays in normal tendon development. We propose that the increased loading that developing postnatal tendons experience with the onset of locomotor behavior impacts tendon formation. The objective of this study was to assess the onset of spontaneous weight-bearing locomotion in postnatal day (P) 1, 5, and 10 rats, and characterize the relationship between locomotion and the mechanical development of weight-bearing and non-weight-bearing tendons. Movement was video recorded and scored to determine non-weight-bearing, partial weight-bearing, and full weight-bearing locomotor behavior at P1, P5, and P10. Achilles tendons, as weight-bearing tendons, and tail tendons, as non-weight-bearing tendons, were mechanically evaluated. We observed a significant increase in locomotor behavior in P10 rats, compared to P1 and P5. We also found corresponding significant differences in the maximum force, stiffness, displacement at maximum force, and cross-sectional area in Achilles tendons, as a function of postnatal age. However, the maximum stress, strain at maximum stress, and elastic modulus remained constant. Tail tendons of P10 rats had significantly higher maximum force, maximum stress, elastic modulus, and stiffness compared to P5. Our results suggest that the onset of locomotor behavior may be providing the mechanical cues regulating postnatal tendon growth, and their mechanical development may proceed differently in weight-bearing and non-weight-bearing tendons. Further analysis of how this loading affects developing tendons in vivo may inform future engineering approaches aiming to apply such mechanical cues to regulate engineered tendon formation in vitro.
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19
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Javidi M, McGowan CP, Schiele NR, Lin DC. Tendons from kangaroo rats are exceptionally strong and tough. Sci Rep 2019; 9:8196. [PMID: 31160640 PMCID: PMC6546749 DOI: 10.1038/s41598-019-44671-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 05/17/2019] [Indexed: 11/14/2022] Open
Abstract
Tendons must be able to withstand the forces generated by muscles and not fail. Accordingly, a previous comparative analysis across species has shown that tendon strength (i.e., failure stress) increases for larger species. In addition, the elastic modulus increases proportionally to the strength, demonstrating that the two properties co-vary. However, some species may need specially adapted tendons to support high performance motor activities, such as sprinting and jumping. Our objective was to determine if the tendons of kangaroo rats (k-rat), small bipedal animals that can jump as high as ten times their hip height, are an exception to the linear relationship between elastic modulus and strength. We measured and compared the material properties of tendons from k-rat ankle extensor muscles to those of similarly sized white rats. The elastic moduli of k-rat and rat tendons were not different, but k-rat tendon failure stresses were much larger than the rat values (nearly 2 times larger), as were toughness (over 2.5 times larger) and ultimate strain (over 1.5 times longer). These results support the hypothesis that the tendons from k-rats are specially adapted for high motor performance, and k-rat tendon could be a novel model for improving tissue engineered tendon replacements.
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Affiliation(s)
- Mehrdad Javidi
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, PO Box 646515, Pullman, WA, 99164, USA
| | - Craig P McGowan
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, MS 3051, Moscow, ID, 83844, USA.,WWAMI Medical Education Program, University of Idaho, 875 Perimeter Drive, MS 4207, Moscow, ID, 83844, USA.,Washington Center for Muscle Biology, Washington State University, PO Box 646515, Pullman, WA, 99164, USA
| | - Nathan R Schiele
- Department of Biological Engineering, University of Idaho, 875 Perimeter Dr. MS 0904, Moscow, ID, 83844, USA
| | - David C Lin
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, PO Box 646515, Pullman, WA, 99164, USA. .,Washington Center for Muscle Biology, Washington State University, PO Box 646515, Pullman, WA, 99164, USA. .,Department of Integrative Physiology and Neuroscience, Washington State University, PO Box 647620, Pullman, WA, 99164, USA.
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20
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Lin X, Huang M, Yin G, Zhang J, Zhang Z, Lai P, Yan B, Chen Y, Jin D, Wang L. Characterization of a Novel Calcific Achilles Tendinopathy Model in Mice: Contralateral Tendinopathy Induced by Unilateral Tenotomy. Calcif Tissue Int 2018; 103:698-707. [PMID: 30132146 DOI: 10.1007/s00223-018-0465-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 08/08/2018] [Indexed: 01/14/2023]
Abstract
Achilles tendinopathy is a significant clinical disease characterized by activity-related pain, focal movement limitation, and intratendinous imaging changes. However, treatment of Achilles tendinopathy has been based mainly on theoretical rationale and clinical experience because of its unclear underlying pathogenesis and mechanism. The purpose of the study was to develop a simple but reproducible overuse-induced animal model of Achilles tendinopathy in mice to better understand the underlying mechanism and prevent calcific Achilles tendinopathy. A total of 80 C57/B6 mice (8 or 9 weeks old) were employed and randomly divided into control and experimental groups. Unilateral Achilles tenotomy was performed on the right hind limbs in the experiment group. 12 weeks after unilateral Achilles tenotomy, the onset of Achilles tendinopathy in the contralateral Achilles tendon was determined by radiological assessment, histologic analysis, electron microscopy observation, and biomechanical test. The onset of calcific Achilles tendinopathy in contralateral Achilles tendon was confirmed after 12 weeks of unilateral tenotomy. The contralateral Achilles tendon in the experimental group was characterized as hypercellularity, neovascularization, and fused collagen fiber disarrangement, compared with the control group. Importantly, intra-tendon endochondral ossification and calcaneus deformity were featured in contralateral Achilles tendon. In addition, poor biomechanical properties in the contralateral Achilles tendon revealed the incidence of Achilles tendinopathy. We hereby introduce a novel, simple, but reproducible spontaneous contralateral calcific Achilles tendinopathy model in mice, which represents overuse conditions during tendinopathy development in humans. It should be a useful tool to further study the underlying pathogenesis of calcific Achilles tendinopathy.
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Affiliation(s)
- Xuemei Lin
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China
| | - Minjun Huang
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China
| | - Ganghui Yin
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China
| | - Jie Zhang
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China
| | - Zhongmin Zhang
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China
| | - Pinglin Lai
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China
| | - Bo Yan
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China
| | - Yuhui Chen
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China
| | - Dadi Jin
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China.
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China.
| | - Liang Wang
- Department of Orthopaedics, The Third Affiliated Hospital of Southern Medical University, 183 West Zhongshan Avenue, Guangzhou, 510665, Guangdong, People's Republic of China.
- Academy of Orthopaedics, Guangdong Province, Guangzhou, 510665, Guangdong, People's Republic of China.
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21
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Magnusson SP, Kjaer M. The impact of loading, unloading, ageing and injury on the human tendon. J Physiol 2018; 597:1283-1298. [PMID: 29920664 DOI: 10.1113/jp275450] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 05/30/2018] [Indexed: 12/28/2022] Open
Abstract
A tendon transfers force from the contracting muscle to the skeletal system to produce movement and is therefore a crucial component of the entire muscle-tendon complex and its function. However, tendon research has for some time focused on mechanical properties without any major appreciation of potential cellular and molecular changes. At the same time, methodological developments have permitted determination of the mechanical properties of human tendons in vivo, which was previously not possible. Here we review the current understanding of how tendons respond to loading, unloading, ageing and injury from cellular, molecular and mechanical points of view. A mechanistic understanding of tendon tissue adaptation will be vital for development of adequate guidelines in physical training and rehabilitation, as well as for optimal injury treatment.
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Affiliation(s)
- S Peter Magnusson
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Copenhagen, NV.,Department of Physical and Occupational Therapy Bispebjerg Hospital, Copenhagen, NV.,Center for Healthy Aging, Department of Health and Medical Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Michael Kjaer
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Copenhagen, NV.,Center for Healthy Aging, Department of Health and Medical Sciences, University of Copenhagen, Copenhagen N, Denmark
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22
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Thampatty BP, Wang JHC. Mechanobiology of young and aging tendons: In vivo studies with treadmill running. J Orthop Res 2018; 36:557-565. [PMID: 28976604 PMCID: PMC5839954 DOI: 10.1002/jor.23761] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 09/13/2017] [Indexed: 02/04/2023]
Abstract
Tendons are unique in the sense that they are constantly subjected to large mechanical loads and that they contain tendon-specific cells, including tenocytes and tendon stem/progenitor cells. The responses of these cells to mechanical loads can be anabolic or catabolic and as a result, change the biological properties of the tendon itself that may be beneficial or detrimental. On the other hand, aging also induces aberrant changes in cellular expression of various genes and production of various types of matrix proteins in the tendon, and consequently lead to tendon degeneration and impaired healing in aging tendons; both could be improved by moderate physiological mechanical loading such as treadmill running. This article gives an overview on the mechanobiology research of young and aging animal tendons using treadmill running model. The challenges in such treadmill running studies are also discussed. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:557-565, 2018.
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Affiliation(s)
- Bhavani P. Thampatty
- MechanoBiology Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, 210 Lothrop street, BST, E1640, Pittsburgh, PA 15213, USA
| | - James H-C. Wang
- MechanoBiology Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, 210 Lothrop street, BST, E1640, Pittsburgh, PA 15213, USA
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23
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Achilles tendon compositional and structural properties are altered after unloading by botox. Sci Rep 2017; 7:13067. [PMID: 29026107 PMCID: PMC5638919 DOI: 10.1038/s41598-017-13107-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 09/18/2017] [Indexed: 02/07/2023] Open
Abstract
Tendon function and homeostasis rely on external loading. This study investigates the biological mechanisms behind tendon biomechanical function and how the mechanical performance is affected by reduced daily loading. The Achilles tendons of 16 weeks old female Sprague Dawley rats (n = 40) were unloaded for 5 weeks by inducing muscle paralysis with botulinum toxin injections in the right gastrocnemius and soleus muscles. The contralateral side was used as control. After harvest, the tendons underwent biomechanical testing to assess viscoelasticity (n = 30 rats) and small angle X-ray scattering to determine the structural properties of the collagen fibrils (n = 10 rats). Fourier transform infrared spectroscopy and histological staining (n = 10 rats) were performed to investigate the collagen and proteoglycan content. The results show that the stiffness increased in unloaded tendons, together with an increased collagen content. Creep and axial alignment of the collagen fibers were reduced. Stress-relaxation increased whereas hysteresis was reduced in response to unloading with botox treatment. Our findings indicate that altered matrix deposition relies on mechanical loading to reorganize the newly formed tissue, without which the viscoelastic behavior is impaired. The results demonstrate that reduced daily loading deprives tendons of their viscoelastic properties, which could increase the risk of injury.
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24
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Marqueti RC, Durigan JLQ, Oliveira AJS, Mekaro MS, Guzzoni V, Aro AA, Pimentel ER, Selistre-de-Araujo HS. Effects of aging and resistance training in rat tendon remodeling. FASEB J 2017; 32:353-368. [PMID: 28899880 DOI: 10.1096/fj.201700543r] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/28/2017] [Indexed: 12/21/2022]
Abstract
In elderly persons, weak tendons contribute to functional limitations, injuries, and disability, but resistance training can attenuate this age-related decline. We evaluated the effects of resistance training on the extracellular matrix (ECM) of the calcaneal tendon (CT) in young and old rats and its effect on tendon remodeling. Wistar rats aged 3 mo (young, n = 30) and 20 mo (old, n = 30) were divided into 4 groups: young sedentary, young trained, old sedentary (OS), and old trained (OT). The training sessions were conducted over a 12-wk period. Aging in sedentary rats showed down-regulation in key genes that regulated ECM remodeling. Moreover, the OS group showed a calcification focus in the distal region of the CT, with reduced blood vessel volume density. In contrast, resistance training was effective in up-regulating connective tissue growth factor, VEGF, and decorin gene expression in old rats. Resistance training also increased proteoglycan content in young and old rats in special small leucine-rich proteoglycans and blood vessels and prevented calcification in OT rats. These findings confirm that resistance training is a potential mechanism in the prevention of aging-related loss in ECM and that it attenuates the detrimental effects of aging in tendons, such as ruptures and tendinopathies.-Marqueti, R. C., Durigan, J. L. Q., Oliveira, A. J. S., Mekaro, M. S., Guzzoni, V., Aro, A. A., Pimentel, E. R., Selistre-de-Araujo, H. S. Effects of aging and resistance training in rat tendon remodeling.
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Affiliation(s)
- Rita C Marqueti
- University of Brasília (UnB), Brasília, Distrito Federal, Brazil;
| | - João L Q Durigan
- University of Brasília (UnB), Brasília, Distrito Federal, Brazil
| | | | | | - Vinicius Guzzoni
- Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Andrea A Aro
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Edson Rosa Pimentel
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.,Heminio Ometto University Center (UNIARARAS), Araras, São Paulo, Brazil
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25
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Temporal Healing of Achilles Tendons After Injury in Rodents Depends on Surgical Treatment and Activity. J Am Acad Orthop Surg 2017; 25:635-647. [PMID: 28837456 PMCID: PMC5603242 DOI: 10.5435/jaaos-d-16-00620] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
INTRODUCTION Achilles tendon ruptures affect 15 of 100,000 women and 55 of 100,000 men each year. Controversy continues to exist regarding optimal treatment and rehabilitation protocols. The objective of this study was to investigate the temporal effects of surgical repair and immobilization or activity on Achilles tendon healing and limb function after complete transection in rodents. METHODS Injured tendons were repaired (n = 64) or left nonrepaired (n = 64). The animals in both cohorts were further randomized into groups immobilized in plantar flexion for 1, 3, or 6 weeks that later resumed cage and treadmill activity for 5, 3, or 0 weeks, respectively (n = 36 for each regimen), which were euthanized at 6 weeks after injury, or into groups immobilized for 1 week and then euthanized (n = 20). RESULTS At 6 weeks after injury, the groups that had 1 week of immobilization and 5 weeks of activity had increased range of motion and decreased ankle joint toe stiffness compared with the groups that had 3 weeks of immobilization and 3 weeks of activity. The groups with 6 weeks of immobilization and no activity period had decreased tendon cross-sectional area but increased tendon echogenicity and collagen alignment. Surgical treatment dramatically decreased fatigue cycles to failure in repaired tendons from groups with 1 week of immobilization and 5 weeks of activity. Normalized comparisons between 1-week and 6-week postinjury data demonstrated that changes in tendon healing properties (area, alignment, and echogenicity) were maximized by 1 week of immobilization and 5 weeks of activity, compared with 6 weeks of immobilization and no activity period. DISCUSSION This study builds on an earlier study of Achilles tendon fatigue mechanics and functional outcomes during early healing by examining the temporal effects of different immobilization and/or activity regimens after initial postinjury immobilization. CONCLUSION This study demonstrates how the temporal postinjury healing response of rodent Achilles tendons depends on both surgical treatment and the timing of immobilization/activity timing. The different pattern of healing and qualities of repaired and nonrepaired tendons suggest that two very different healing processes may occur, depending on the chosen immobilization/activity regimen.
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26
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Rooney SI, Torino DJ, Baskin R, Vafa RP, Kuntz AF, Soslowsky LJ. Rat supraspinatus tendon responds acutely and chronically to exercise. J Appl Physiol (1985) 2017; 123:757-763. [PMID: 28663377 DOI: 10.1152/japplphysiol.00368.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 06/21/2017] [Accepted: 06/27/2017] [Indexed: 12/24/2022] Open
Abstract
The objective of this study was to identify acute responses and chronic adaptations of supraspinatus tendon to noninjurious exercise. We hypothesized that chronic exercise (EX) increases tendon mechanical properties, and a single exercise bout increases matrix metalloproteinase (MMP) activity acutely. Rats were divided into acute or chronic EX or cage activity groups. Animals in acute EX groups were euthanized, 3, 12, 24, 48, or 72 h upon completion of a single bout of exercise (10 m/min, 1 h) on a flat treadmill. Animals in chronic EX groups walked on a flat treadmill for 3 days or 1, 2, or 8 wk. Tendon histology, MMP activity, and mechanics were measured. A single bout of exercise trended toward reducing tendon mechanical properties, but 2 or 8 wk of chronic EX increased tendon mechanics. Cell density was not affected. Cells became rounder with chronic EX. All tendons were highly organized. MMP activity decreased after a single bout of exercise and returned to baseline by 72 h. MMP activity decreased after 8 wk of chronic EX. Decreased MMP activity may indicate an anabolic instead of catabolic response in contrast to injury. Results suggest that mild, acute decreases in MMP activity and tendon mechanics following a single exercise bout lead to enhanced tendon mechanical adaptations with repeated exercise bouts. This study defines acute and chronic changes of MMP activity, mechanical properties, and histology of the rat supraspinatus tendon in response to beneficial exercise and proposes a mechanism by which acute responses translate to chronic adaptations.NEW & NOTEWORTHY The line between beneficial exercise and overuse has not been elucidated. This study defines the acute and chronic temporal response to exercise of supraspinatus tendon in an in vivo model. We found that decreased matrix metalloproteinase activity and tendon mechanics after a single bout of exercise are followed by beneficial chronic adaptations of the tendon with repeated bouts. How the acute responses to exercise lead to chronic adaptations may distinguish beneficial exercise from overuse.
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Affiliation(s)
| | - Daniel J Torino
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rachel Baskin
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rameen P Vafa
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Andrew F Kuntz
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Louis J Soslowsky
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania
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27
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Gao S, Tang K, Zhang J, Li P, Yang Z, Cui H, Yang M, Tang H, Zhou M. [Effect of different intensity treadmill training on repair of micro-injured Achilles tendon in rats]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2017; 31:574-581. [PMID: 29798548 DOI: 10.7507/1002-1892.201611054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Objective To explore the effect of different intensity treadmill training on the repair of micro-injured Achilles tendon induced by collagenase in rats. Methods Seventy-two 8-week-old male Sprague Dawley rats (weighing, 200-250 g) were selected. After adaptive treadmill training for 1 week, rats were injected with 30 μL type I collagenase solution (10 mg/mL) into both Achilles tendons to make micro-injured Achilles tendon models. After 1 week of cage feeding, the rats were randomly divided into 3 groups: the control group, the low-intensity group, and the high-intensity group, 24 rats each group. The rats in control group could move freely, and the rats underwent daily treadmill training at the intensity of 13 m/min and 20 min/d in the low-intensity group and at the intensity of 17 m/min and 60 min/d in the high-intensity group. At immediate, 1 week, and 4 weeks after training, bilateral Achilles tendons were collected from 8 rats of each group for gross observation, histological analysis, and mechanical testing. Results At immediate after training, there was no significant difference in the gross observation, histological observation, and biomechanical properties of the Achilles tendon between groups ( P>0.05). The gross observation showed connective tissue hyperplasia near Achilles tendon and lackluster tendon in each group at 1 week; hyperplasia significantly reduced in the low-intensity group when compared with the control group, and there were more connective tissue and a large number of neovascularization in the high-intensity group at 4 weeks. At 1 week, there was no significant difference in the semi-quantitative histological total score between groups ( P>0.05), but there were significant differences in vascularity between low-intensity group or high-intensity group and control group ( P<0.05). At 4 weeks, the semi-quantitative histological total score was significantly higher in high-intensity group than control group and low-intensity group ( P<0.05), and in control group than low-intensity group ( P<0.05). There were significant differences in collagen arrangement, cell morphology, abnormal cells, and vascularity between low-intensity group and high-intensity group or control group ( P<0.05). And there was significant difference in abnormal cells between high-intensity group and control group ( P<0.05). The mechanical testing showed that there was no significant difference in cross-sectional area of the Achilles tendon, the ultimate force, tensile strength, and elastic modulus between groups at 1 week ( P>0.05); the low-intensity group was significantly higher than the control group in the ultimate force and the tensile strength ( P<0.05), and than high-intensity group in the ultimate force and elastic modulus ( P<0.05), but no significant difference was found in the other indexes between groups ( P>0.05) at 4 weeks. Conclusion Low-intensity treadmill training can promote the repair of rat micro-injured Achilles tendon induced by collagenase.
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Affiliation(s)
- Shang Gao
- Department of Orthopedics, Orthopedic Center of Chinese PLA, Southwest Hospital, Third Military Medical University, Chongqing, 400038, P.R.China
| | - Kanglai Tang
- Department of Orthopedics, Orthopedic Center of Chinese PLA, Southwest Hospital, Third Military Medical University, Chongqing, 400038,
| | - Jiqiang Zhang
- Department of Neurobiology, Third Military Medical University, Chongqing, 400038, P.R.China
| | - Pao Li
- Department of Orthopedics, Orthopedic Center of Chinese PLA, Southwest Hospital, Third Military Medical University, Chongqing, 400038, P.R.China
| | - Zhijin Yang
- Department of Orthopedics, Orthopedic Center of Chinese PLA, Southwest Hospital, Third Military Medical University, Chongqing, 400038, P.R.China
| | - Haifeng Cui
- Department of Orthopedics, Orthopedic Center of Chinese PLA, Southwest Hospital, Third Military Medical University, Chongqing, 400038, P.R.China
| | - Mingyu Yang
- Department of Orthopedics, Orthopedic Center of Chinese PLA, Southwest Hospital, Third Military Medical University, Chongqing, 400038, P.R.China
| | - Hong Tang
- Department of Orthopedics, Orthopedic Center of Chinese PLA, Southwest Hospital, Third Military Medical University, Chongqing, 400038, P.R.China
| | - Mei Zhou
- Department of Orthopedics, Orthopedic Center of Chinese PLA, Southwest Hospital, Third Military Medical University, Chongqing, 400038, P.R.China
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28
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Katsma MS, Patel SH, Eldon E, Corbell KA, Shimkus KL, Fluckey JD, Carroll CC. The influence of chronic IL-6 exposure, in vivo, on rat Achilles tendon extracellular matrix. Cytokine 2017; 93:10-14. [PMID: 28412025 DOI: 10.1016/j.cyto.2017.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/04/2017] [Accepted: 04/05/2017] [Indexed: 11/25/2022]
Abstract
When compared to placebo, acetaminophen (APAP) reduces tendon stiffness and collagen cross-linking. APAP also enhances the exercise-induced increase in peritendinous levels of IL-6. Elevated levels of IL-6 are associated with tendinopathy, thus we hypothesized that chronic, elevated peritendinous IL-6 would alter tendon extracellular matrix (ECM). IL-6 (∼3000pgml-1) was injected (3dwk-1 for 8-wks) into the Achilles peritendinous region of male Wistar rats (n=16) with the opposite leg serving as a sham. Fractional synthesis rates (FSR) were determined using deuterium oxide. Collagen (hydroxyproline) and hydroxylysl pyridinoline (HP) cross-linking were analyzed by HPLC. ECM and IL-6 related genes were evaluated using qRT-PCR. Relative to sham, collagen (Col) 1a1 but not Col3a1 expression was suppressed (47%) in tendons exposed to IL-6 (p<0.05). Lysyl oxidase (LOX) and MMP-1 expression were also reduced (37%) in IL-6 treated tendons (p<0.05). Relative to sham the expression of MMP-2, -3, -9, and TIMP-1 were not altered by IL-6 treatment (p>0.05). Interleukin-6 receptor subunit beta precursor (IL6st) was lower (16%) in IL-6 treated tendons when compared to sham (p<0.05). Suppressor of cytokine signaling 3 (Socs3), signal transducer and activator of transcription 3 (STAT3), and protein inhibitor of activated STAT 1 (Pias1) were not altered by IL-6 exposure (p>0.05). Neither collagen nor cross-linking content were altered by IL-6 (p>0.05). Additionally, IL-6 treatment did not alter tendon FSR. Chronic treatment with physiologically relevant levels of IL-6 suppresses expression of Col1a1 and LOX while also altering expression of select MMPs but does not alter Achilles tendon collagen synthesis.
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Affiliation(s)
- Mark S Katsma
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA
| | - Shivam H Patel
- Department of Health and Kinesiology, Purdue University, West Lafayette, IN, USA
| | - Erica Eldon
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA
| | - Kathryn A Corbell
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA
| | | | | | - Chad C Carroll
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA; Department of Health and Kinesiology, Purdue University, West Lafayette, IN, USA.
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29
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Mehdizadeh A, Gardiner BS, Lavagnino M, Smith DW. Predicting tenocyte expression profiles and average molecular concentrations in Achilles tendon ECM from tissue strain and fiber damage. Biomech Model Mechanobiol 2017; 16:1329-1348. [DOI: 10.1007/s10237-017-0890-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 02/18/2017] [Indexed: 11/28/2022]
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30
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Resistance training minimizes the biomechanical effects of aging in three different rat tendons. J Biomech 2017; 53:29-35. [DOI: 10.1016/j.jbiomech.2016.12.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/02/2016] [Accepted: 12/19/2016] [Indexed: 11/18/2022]
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31
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Potter RM, Huynh RT, Volper BD, Arthur KA, D'Lugos AC, Sørensen MA, Magnusson SP, Dickinson JM, Hale TM, Carroll CC. Impact of TGF-β inhibition during acute exercise on Achilles tendon extracellular matrix. Am J Physiol Regul Integr Comp Physiol 2016; 312:R157-R164. [PMID: 27927626 DOI: 10.1152/ajpregu.00439.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/14/2016] [Accepted: 12/01/2016] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to evaluate the role of TGF-β1 in regulating tendon extracellular matrix after acute exercise. Wistar rats exercised (n = 15) on a treadmill for four consecutive days (60 min/day) or maintained normal cage activity. After each exercise bout, the peritendinous space of each Achilles tendon was injected with a TGF-β1 receptor inhibitor or sham. Independent of group, tendons injected with inhibitor exhibited ~50% lower Smad 3 (Ser423/425) (P < 0.05) and 2.5-fold greater ERK1/2 phosphorylation (P < 0.05) when compared with sham (P < 0.05). Injection of the inhibitor did not alter collagen content in either group (P > 0.05). In exercised rats, hydroxylyslpyridinoline content and collagen III expression were lower (P < 0.05) in tendons injected with inhibitor when compared with sham. In nonexercised rats, collagen I and lysyl oxidase (LOX) expression was lower (P < 0.05) in tendons injected with inhibitor when compared with sham. Decorin expression was not altered by inhibitor in either group (P > 0.05). On the basis of evaluation of hematoxylin and eosin (H&E) stained cross sections, cell numbers were not altered by inhibitor treatment in either group (P > 0.05). Evaluation of H&E-stained sections revealed no effect of inhibitor on collagen fibril morphology. In contrast, scores for regional variation in cellularity decreased in exercised rats (P < 0.05). No differences in fiber arrangement, structure, and nuclei form were noted in either group (P > 0.05). Our findings suggest that TGF-β1 signaling is necessary for the regulation of tendon cross-link formation, as well as collagen and LOX gene transcription in an exercise-dependent manner.
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Affiliation(s)
- Ross M Potter
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona
| | - Richard T Huynh
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona.,Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona
| | - Brent D Volper
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona.,Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona
| | - Kathryn A Arthur
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona
| | - Andrew C D'Lugos
- Arizona State University, School of Nutrition and Health Promotion, Healthy Lifestyles Research Center, Exercise Science and Health Promotion, Phoenix, Arizona
| | - Mikkel A Sørensen
- Musculoskeletal Rehabilitation Research Unit & Institute of Sports Medicine Copenhagen Bispebjerg Hospital Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - S Peter Magnusson
- Musculoskeletal Rehabilitation Research Unit & Institute of Sports Medicine Copenhagen Bispebjerg Hospital Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Jared M Dickinson
- Arizona State University, School of Nutrition and Health Promotion, Healthy Lifestyles Research Center, Exercise Science and Health Promotion, Phoenix, Arizona
| | - Taben M Hale
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona
| | - Chad C Carroll
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona; .,Department of Health and Kinesiology, Purdue University, West Lafayette, Indiana
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Freedman BR, Gordon JA, Bhatt PB, Pardes AM, Thomas SJ, Sarver JJ, Riggin CN, Tucker JJ, Williams AW, Zanes RC, Hast MW, Farber DC, Silbernagel KG, Soslowsky LJ. Nonsurgical treatment and early return to activity leads to improved Achilles tendon fatigue mechanics and functional outcomes during early healing in an animal model. J Orthop Res 2016; 34:2172-2180. [PMID: 27038306 PMCID: PMC5047851 DOI: 10.1002/jor.23253] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/29/2016] [Indexed: 02/04/2023]
Abstract
Achilles tendon ruptures are common and devastating injuries; however, an optimized treatment and rehabilitation protocol has yet to be defined. Therefore, the objective of this study was to investigate the effects of surgical repair and return to activity on joint function and Achilles tendon properties after 3 weeks of healing. Sprague-Dawley rats (N = 100) received unilateral blunt transection of their Achilles tendon. Animals were then randomized into repaired or non-repaired treatments, and further randomized into groups that returned to activity after 1 week (RTA1) or after 3 weeks (RTA3) of limb casting in plantarflexion. Limb function, passive joint mechanics, and tendon properties (mechanical, organizational using high frequency ultrasound, histological, and compositional) were evaluated. Results showed that both treatment and return to activity collectively affected limb function, passive joint mechanics, and tendon properties. Functionally, RTA1 animals had increased dorsiflexion ROM and weight bearing of the injured limb compared to RTA3 animals 3-weeks post-injury. Such functional improvements in RTA1 tendons were evidenced in their mechanical fatigue properties and increased cross sectional area compared to RTA3 tendons. When RTA1 was coupled with nonsurgical treatment, superior fatigue properties were achieved compared to repaired tendons. No differences in cell shape, cellularity, GAG, collagen type I, or TGF-β staining were identified between groups, but collagen type III was elevated in RTA3 repaired tendons. The larger tissue area and increased fatigue resistance created in RTA1 tendons may prove critical for optimized outcomes in early Achilles tendon healing following complete rupture. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2172-2180, 2016.
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Affiliation(s)
- BR Freedman
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - JA Gordon
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - PB Bhatt
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - AM Pardes
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - SJ Thomas
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA,Department of Kinesiology, Temple University, Philadelphia, PA, USA
| | - JJ Sarver
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA,Department of Biomedical Engineering, Drexel University, Philadelphia, PA, USA
| | - CN Riggin
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - JJ Tucker
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - AW Williams
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - RC Zanes
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - MW Hast
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - DC Farber
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - KG Silbernagel
- Department of Physical Therapy, University of Delaware, Newark, DE, USA
| | - LJ Soslowsky
- McKay Orthopaedic Laboratory, University of Pennsylvania, Philadelphia, PA, USA
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33
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Svensson RB, Heinemeier KM, Couppé C, Kjaer M, Magnusson SP. Effect of aging and exercise on the tendon. J Appl Physiol (1985) 2016; 121:1237-1246. [DOI: 10.1152/japplphysiol.00328.2016] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 04/29/2016] [Indexed: 12/27/2022] Open
Abstract
Here, we review the literature on how tendons respond and adapt to ageing and exercise. With respect to aging, there are considerable changes early in life, but this seems to be maturation rather than aging per se. In vitro data indicate that aging is associated with a decreased potential for cell proliferation and a reduction in the number of stem/progenitor-like cells. Further, there is persuasive evidence that turnover in the core of the tendon after maturity is very slow or absent. Tendon fibril diameter, collagen content, and whole tendon size appear to be largely unchanged with aging, while glycation-derived cross-links increase substantially. Mechanically, aging appears to be associated with a reduction in modulus and strength. With respect to exercise, tendon cells respond by producing growth factors, and there is some support for a loading-induced increase in tendon collagen synthesis in humans, which likely reflects synthesis at the very periphery of the tendon rather than the core. Average collagen fibril diameter is largely unaffected by exercise, while there can be some hypertrophy of the whole tendon. In addition, it seems that resistance training can yield increased stiffness and modulus of the tendon and may reduce the amount of glycation. Exercise thereby tends to counteract the effects of aging.
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Affiliation(s)
- Rene B. Svensson
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Katja Maria Heinemeier
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; and
| | - Christian Couppé
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Musculoskeletal Rehabilitation Research Unit, Bispebjerg Hospital, Denmark
| | - Michael Kjaer
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; and
| | - S. Peter Magnusson
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; and
- Musculoskeletal Rehabilitation Research Unit, Bispebjerg Hospital, Denmark
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34
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Xu SY, Li SF, Ni GX. Strenuous Treadmill Running Induces a Chondrocyte Phenotype in Rat Achilles Tendons. Med Sci Monit 2016; 22:3705-3712. [PMID: 27742920 PMCID: PMC5070615 DOI: 10.12659/msm.897726] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Although tendinopathy is common, its underlying pathogenesis is poorly understood. This study aimed to investigate the possible pathogenesis of tendinopathy. MATERIAL AND METHODS In this study, a total of 24 rats were randomly and evenly divided into a control (CON) group and a strenuous treadmill running (STR) group. Animals in the STR group were subjected to a 12-week treadmill running protocol. Subsequently, all Achilles tendons were harvested to perform histological observation or biochemical analyses. RESULTS Histologically, hypercellularity and round cells, as well as disorganized collagen fibrils, were presented in rat Achilles tendon sections from the STR group. Furthermore, our results showed that the expression of aggrecan, collagen type II (Col II), and Sex-Determining Region Y Box 9 (Sox 9) were markedly increased in the STR group compared with that in the CON group. Additionally, the mRNA expression of bone morphogenetic protein-2 (BMP-2) and biglycan was significantly up-regulated in the STR group in contrast to that in CON group. CONCLUSIONS These results suggest that a 12-week strenuous treadmill running regimen can induce chondrocyte phenotype in rat Achilles tendons through chondrogenic differentiation of tendon stem cells (TSCs) by BMP-2 signaling.
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Affiliation(s)
- Shao-Yong Xu
- Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, P.R. China
| | - Shu-Fen Li
- Laboratory Medicine Center, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, P.R. China
| | - Guo-Xin Ni
- Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, P.R. China
- Department of Rehabilitation Medicine, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, P.R. China
- Corresponding Author: Guo-Xin Ni, e-mail:
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35
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Couppé C, Svensson RB, Heinemeier KM, Thomsen EW, Bayer ML, Christensen L, Kjær M, Magnusson SP, Schjerling P. Quantification of cell density in rat Achilles tendon: development and application of a new method. Histochem Cell Biol 2016; 147:97-102. [PMID: 27565969 DOI: 10.1007/s00418-016-1482-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2016] [Indexed: 01/03/2023]
Abstract
Increased tendon cell nuclei density (TCND) has been proposed to induce tendon mechanical adaptations. However, it is unknown whether TCND is increased in tendon tissue after mechanical loading and whether such an increase can be quantified in a reliable manner. The aim of this study was to develop a reliable method for quantification of TCND and to investigate potential changes in TCND in rat Achilles tendons in response to 12 weeks of running. Eight adult male Sprague-Dawley rats ran (RUN) on a treadmill with 10° incline, 1 h/day, 5 days/wk (17-20 m/min) for 12 weeks (which improved tendon mechanical properties) and were compared with 11 control rats (SED). Tissue-Tek-embedded cryosections (10 µm) from the mid region of the Achilles tendon were cut longitudinally on a cryostat. Sections were stained with alcian blue and picrosirius red. One blinded investigator counted the number of tendon cell nuclei 2-3 times in three separate regions of the mid longitudinal tendon sections with fields of 390 μm × 280 μm. Unpaired t tests were used for the statistical analysis (mean ± SE). Typical Error % for replicate counts was 5.5 and 14 % coefficient of variation for the three regions. There was no difference in TCND between running rats versus control rats (nuclei per image (≈105 μm2): RUN, 152 ± 9; SED, 146 ± 8, p = 0.642). This new method provided reproducible quantification of TCND. There was no difference in TCND despite improvements in tendon mechanics, which suggests that cell number is not a major cause for altered tendon mechanical properties with loading.
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Affiliation(s)
- Christian Couppé
- IOC Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Building 8, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark. .,Musculoskeletal Rehabilitation Research Unit, Department of Physical Therapy, Bispebjerg Hospital, Copenhagen, Denmark.
| | - René B Svensson
- IOC Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Building 8, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark
| | - Katja M Heinemeier
- IOC Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Building 8, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emilie Wøjdemann Thomsen
- IOC Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Building 8, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark
| | - Monika Lucia Bayer
- IOC Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Building 8, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark
| | | | - Michael Kjær
- IOC Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Building 8, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark
| | - S Peter Magnusson
- IOC Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Building 8, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark.,Musculoskeletal Rehabilitation Research Unit, Department of Physical Therapy, Bispebjerg Hospital, Copenhagen, Denmark
| | - Peter Schjerling
- IOC Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Building 8, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark
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36
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Subramanian A, Schilling TF. Tendon development and musculoskeletal assembly: emerging roles for the extracellular matrix. Development 2016; 142:4191-204. [PMID: 26672092 DOI: 10.1242/dev.114777] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Tendons and ligaments are extracellular matrix (ECM)-rich structures that interconnect muscles and bones. Recent work has shown how tendon fibroblasts (tenocytes) interact with muscles via the ECM to establish connectivity and strengthen attachments under tension. Similarly, ECM-dependent interactions between tenocytes and cartilage/bone ensure that tendon-bone attachments form with the appropriate strength for the force required. Recent studies have also established a close lineal relationship between tenocytes and skeletal progenitors, highlighting the fact that defects in signals modulated by the ECM can alter the balance between these fates, as occurs in calcifying tendinopathies associated with aging. The dynamic fine-tuning of tendon ECM composition and assembly thus gives rise to the remarkable characteristics of this unique tissue type. Here, we provide an overview of the functions of the ECM in tendon formation and maturation that attempts to integrate findings from developmental genetics with those of matrix biology.
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Affiliation(s)
- Arul Subramanian
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Thomas F Schilling
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697-2300, USA
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37
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Wood LK, Brooks SV. Ten weeks of treadmill running decreases stiffness and increases collagen turnover in tendons of old mice. J Orthop Res 2016; 34:346-53. [PMID: 25640809 DOI: 10.1002/jor.22824] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 01/07/2015] [Indexed: 02/04/2023]
Abstract
Increased tendon stiffness in response to mechanical loading is well established in young animals. Given that tendons stiffen with aging, we aimed to determine the effect of increased loading on tendons of old animals. We subjected 28-month-old mice to 10 weeks of uphill treadmill running; sedentary 8- and 28-month-old mice served as controls. Following training, plantaris tendon stiffness and modulus were reduced by approximately half, such that the values were not different from those of tendons from adult sedentary animals. The decrease in plantaris tendon stiffness was accompanied by a similar reduction in the levels of advanced glycation end-product protein adducts in tibialis anterior tendons of trained compared with sedentary old mice. In Achilles tendons, elevated mRNA levels for collagen type 1, matrix-metalloproteinase-8, and lysyl oxidase following training suggest that collagen turnover was likely also increased. The dramatic mechanical and structural changes induced by training occurred independent of changes in cell density or tendon morphology. Finally, Achilles tendon calcification was significantly reduced following exercise. These results demonstrate that, in response to exercise, tendons from old animals are capable of replacing damaged and dysfunctional components of extracellular matrix with tissue that is mechanically and structurally comparable to adult tissue.
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Affiliation(s)
- Lauren K Wood
- Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Susan V Brooks
- Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.,Department of Molecular and Integrative Physiology, 109 Zina Pitcher Place, BSRB 2029, Ann Arbor, Michigan, 48109
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38
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Kim BS, Joo YC, Choi BH, Kim KH, Kang JS, Park SR. The effect of dry needling and treadmill running on inducing pathological changes in rat Achilles tendon. Connect Tissue Res 2015; 56:452-60. [PMID: 26076317 DOI: 10.3109/03008207.2015.1052876] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Achilles tendinopathy is a common degenerative condition without a definitive treatment. An adequate chronic animal model of Achilles tendinopathy has not yet been developed. The purpose of this study was to evaluate the individual and combined effects of dry needling and treadmill running on the Achilles tendon of rats. Percutaneous dry needling, designed to physically replicate microrupture of collagen fibers in overloaded tendons, was performed on the right Achilles tendon of 80 Sprague-Dawley rats. The rats were randomly divided into two groups: a treadmill group, which included rats that underwent daily uphill treadmill running (n = 40), and a cage group, which included rats that could move freely within their cages (n = 40). At the end of weeks 1 and 4, 20 rats from each group were sacrificed, and bilateral Achilles tendons were collected. The harvested tendons were subjected to mechanical testing and histological analysis. Dry needling induced histological and mechanical changes in the Achilles tendons at week 1, and the changes persisted at week 4. The needled Achilles tendons of the treadmill group tended to show more severe histological and mechanical changes than those of the cage group, although these differences were not statistically significant. Dry needling combined with free cage activity or treadmill running produced tendinopathy-like changes in rat Achilles tendons up to 4 weeks after injury. Dry needling is an easy procedure with a short induction period and a high success rate, suggesting it may have relevance in the design of an Achilles tendinopathy model.
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Affiliation(s)
- Bom Soo Kim
- a Department of Orthopaedic Surgery , Inha University College of Medicine , Incheon , Korea
| | - Young Chae Joo
- b Department of Pathology , Inha University College of Medicine , Incheon , Korea
| | - Byung Hyune Choi
- c Division of Biomedical and Bioengineering Sciences , Inha University College of Medicine , Incheon , Korea , and
| | - Kil Hwan Kim
- d Department of Physiology , Inha University College of Medicine , Incheon , Korea
| | - Joon Soon Kang
- a Department of Orthopaedic Surgery , Inha University College of Medicine , Incheon , Korea
| | - So Ra Park
- d Department of Physiology , Inha University College of Medicine , Incheon , Korea
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39
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Abstract
Synopsis Tendinopathy is a very common disorder in both recreational and elite athletes. Many individuals have recurrent symptoms that lead to chronic conditions and termination of sports activity. Exercise has become a popular and somewhat efficacious treatment regime, and isolated eccentric exercise has been particularly promoted. In this clinical commentary, we review the relevant evidence for different exercise regimes in tendinopathy rehabilitation, with particular focus on the applied loads that are experienced by the tendon and how the exercise regime may affect these applied loads. There is no convincing clinical evidence to demonstrate that isolated eccentric loading exercise improves clinical outcomes more than other loading therapies. However, the great variation and sometimes insufficient reporting of the details of treatment protocols may hamper the interpretation of what may be the optimal exercise regime with respect to parameters such as load magnitude, speed of movement, and recovery period between exercise sessions. Future studies should control for these loading parameters, evaluate various exercise dosages, and think beyond isolated eccentric exercises to arrive at firm recommendations regarding rehabilitation of individuals with tendinopathies. J Orthop Sports Phys Ther 2015;45(11):853-863. Epub 14 Oct 2015. doi:10.2519/jospt.2015.5910.
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40
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Thompson WR, Keller BV, Davis ML, Dahners LE, Weinhold PS. Low-Magnitude, High-Frequency Vibration Fails to Accelerate Ligament Healing but Stimulates Collagen Synthesis in the Achilles Tendon. Orthop J Sports Med 2015; 3. [PMID: 26086026 PMCID: PMC4467027 DOI: 10.1177/2325967115585783] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Background: Low-magnitude, high-frequency vibration accelerates fracture and wound healing and prevents disuse atrophy in musculoskeletal tissues. Purpose: To investigate the role of low-magnitude, high-frequency vibration as a treatment to accelerate healing of an acute ligament injury and to examine gene expression in the intact Achilles tendon of the injured limb after low-magnitude, high-frequency vibration. Study Design: Controlled laboratory study. Methods: Complete surgical transection of the medial collateral ligament (MCL) was performed in 32 Sprague-Dawley rats, divided into control and low-magnitude, high-frequency vibration groups. Low-magnitude, high-frequency vibration started on postoperative day 2, and rats received vibration for 30 minutes a day for 12 days. All rats were sacrificed 2 weeks after the operation, and their intact and injured MCLs were biomechanically tested or used for histological analysis. Intact Achilles tendons from the injured limb were evaluated for differences in gene expression. Results: Mechanical testing revealed no differences in the ultimate tensile load or the structural stiffness between the control and vibration groups for either the injured or intact MCL. Vibration exposure increased gene expression of collagen 1 alpha (3-fold), interleukin 6 (7-fold), cyclooxygenase 2 (5-fold), and bone morphogenetic protein 12 (4-fold) in the intact Achilles tendon when compared with control tendons (P < .05). Conclusion: While no differences were observed in the mechanical or histological properties of the fully transected MCL after low-magnitude, high-frequency vibration treatment, significant enhancements in gene expression were observed in the intact Achilles tendon. These included collagen, several inflammatory cytokines, and growth factors critical for tendons. Clinical Relevance: As low-magnitude, high-frequency vibration had no negative effects on ligament healing, vibration therapy may be a useful tool to accelerate healing of other tissues (bone) in multitrauma injuries without inhibiting ligament healing. Additionally, the enhanced gene expression in response to low-magnitude, high-frequency vibration in the intact Achilles tendon suggests the need to further study its potential to accelerate tendon healing in partial injury or repair models.
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Affiliation(s)
- William R Thompson
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, Indianapolis, Indiana, USA
| | - Benjamin V Keller
- Department of Orthopedics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Matthew L Davis
- Department of Orthopedics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Laurence E Dahners
- Department of Orthopedics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Paul S Weinhold
- Department of Orthopedics, University of North Carolina, Chapel Hill, North Carolina, USA
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41
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Docking SI, Rosengarten SD, Cook J. Achilles tendon structure improves on UTC imaging over a 5-month pre-season in elite Australian football players. Scand J Med Sci Sports 2015; 26:557-63. [PMID: 25943892 DOI: 10.1111/sms.12469] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2015] [Indexed: 01/28/2023]
Abstract
Pre-season injuries are common and may be due to a reintroduction of training loads. Tendons are sensitive to changes in load, making them vulnerable to injury in the pre-season. This study investigated changes in Achilles tendon structure on ultrasound tissue characterization (UTC) over the course of a 5-month pre-season in elite male Australian football players. Eighteen elite male Australian football players with no history of Achilles tendinopathy and normal Achilles tendons were recruited. The left Achilles tendon was scanned with UTC to quantify the stability of the echopattern. Participants were scanned at the start and completion of a 5-month pre-season. Fifteen players remained asymptomatic over the course of the pre-season. All four echo-types were significantly different at the end of the pre-season, with the overall echopattern suggesting an improvement in Achilles tendon structure. Three of the 18 participants developed Achilles tendon pain that coincided with a change in the UTC echopattern. This study demonstrates that the UTC echopattern of the Achilles tendon improves over a 5-month pre-season training period, representing increased fibrillar alignment. However, further investigation is needed to elucidate with this alteration in the UTC echopattern results in improved tendon resilience and load capacity.
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Affiliation(s)
- S I Docking
- Monash Tendon Research Group (MONSTERs), Monash University, Melbourne, Victoria, Australia.,Australian Centre of Research into Injury in Sport and its Prevention (ACRISP), Federation University, Ballarat, Victoria, Australia
| | - S D Rosengarten
- Department of Physiotherapy, Faculty of Medicine, Dentistry & Health Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - J Cook
- Monash Tendon Research Group (MONSTERs), Monash University, Melbourne, Victoria, Australia.,Australian Centre of Research into Injury in Sport and its Prevention (ACRISP), Federation University, Ballarat, Victoria, Australia
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42
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Freedman BR, Bade ND, Riggin CN, Zhang S, Haines PG, Ong KL, Janmey PA. The (dys)functional extracellular matrix. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:3153-64. [PMID: 25930943 DOI: 10.1016/j.bbamcr.2015.04.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/11/2015] [Accepted: 04/13/2015] [Indexed: 10/23/2022]
Abstract
The extracellular matrix (ECM) is a major component of the biomechanical environment with which cells interact, and it plays important roles in both normal development and disease progression. Mechanical and biochemical factors alter the biomechanical properties of tissues by driving cellular remodeling of the ECM. This review provides an overview of the structural, compositional, and mechanical properties of the ECM that instruct cell behaviors. Case studies are reviewed that highlight mechanotransduction in the context of two distinct tissues: tendons and the heart. Although these two tissues demonstrate differences in relative cell-ECM composition and mechanical environment, they share similar mechanisms underlying ECM dysfunction and cell mechanotransduction. Together, these topics provide a framework for a fundamental understanding of the ECM and how it may vary across normal and diseased tissues in response to mechanical and biochemical cues. This article is part of a Special Issue entitled: Mechanobiology.
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Affiliation(s)
- Benjamin R Freedman
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Nathan D Bade
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Corinne N Riggin
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Sijia Zhang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Philip G Haines
- Division of Cardiovascular Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Katy L Ong
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul A Janmey
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Physiology, University of Pennsylvania, Philadelphia, PA, USA.
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43
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Abstract
Tendon is a crucial component of the musculoskeletal system. Tendons connect muscle to bone and transmit forces to produce motion. Chronic and acute tendon injuries are very common and result in considerable pain and disability. The management of tendon injuries remains a challenge for clinicians. Effective treatments for tendon injuries are lacking because the understanding of tendon biology lags behind that of the other components of the musculoskeletal system. Animal and cellular models have been developed to study tendon-cell differentiation and tendon repair following injury. These studies have highlighted specific growth factors and transcription factors involved in tenogenesis during developmental and repair processes. Mechanical factors also seem to be essential for tendon development, homeostasis and repair. Mechanical signals are transduced via molecular signalling pathways that trigger adaptive responses in the tendon. Understanding the links between the mechanical and biological parameters involved in tendon development, homeostasis and repair is prerequisite for the identification of effective treatments for chronic and acute tendon injuries.
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Affiliation(s)
- Geoffroy Nourissat
- Service de chirurgie orthopédique et traumatologique, INSERM UMR_S938, DHU i2B, Assistance Publique-Hopitaux de Paris, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, Paris 75012, France
| | - Francis Berenbaum
- Service de rhumatologie, INSERM UMR_S938, DHU i2B, Assistance Publique-Hopitaux de Paris, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, Paris 75012, France
| | - Delphine Duprez
- Centre national de la recherche scientifique UMR 7622, IBPS Developmental Biology Laboratory, F-75005, Paris 5005, France
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44
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Patterson-Kane JC, Rich T. Achilles tendon injuries in elite athletes: lessons in pathophysiology from their equine counterparts. ILAR J 2015; 55:86-99. [PMID: 24936032 DOI: 10.1093/ilar/ilu004] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Superficial digital flexor tendon (SDFT) injury in equine athletes is one of the most well-accepted, scientifically supported companion animal models of human disease (i.e., exercise-induced Achilles tendon [AT] injury). The SDFT and AT are functionally and clinically equivalent (and important) energy-storing structures for which no equally appropriate rodent, rabbit, or other analogues exist. Access to equine tissues has facilitated significant advances in knowledge of tendon maturation and aging, determination of specific exercise effects (including early life), and definition of some of the earliest stages of subclinical pathology. Access to human surgical biopsies has provided complementary information on more advanced phases of disease. Importantly, equine SDFT injuries are only a model for acute ruptures in athletes, not the entire spectrum of human tendonopathy (including chronic tendon pain). In both, pathology begins with a potentially prolonged phase of accumulation of (subclinical) microdamage. Recent work has revealed remarkably similar genetic risk factors, including further evidence that tenocyte dysfunction plays an active role. Mice are convenient but not necessarily accurate models for multiple diseases, particularly at the cellular level. Mechanistic studies, including tendon cell responses to combinations of exercise-associated stresses, require a more thorough investigation of cross-species conservation of key stress pathway auditors. Molecular evidence has provided some context for the poor performance of mouse models; equines may provide better systems at this level. The use of horses may be additionally justifiable based on comparable species longevity, lifestyle factors, and selection pressure by similar infectious agents (e.g., herpesviruses) on general cell stress pathway evolution.
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45
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Jafari L, Vachon P, Beaudry F, Langelier E. Histopathological, biomechanical, and behavioral pain findings of Achilles tendinopathy using an animal model of overuse injury. Physiol Rep 2015; 3:3/1/e12265. [PMID: 25602018 PMCID: PMC4387767 DOI: 10.14814/phy2.12265] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Animal models of forced running are used to study overuse tendinopathy, a common health problem for which clear evidence for effective and accessible treatments is still lacking. In these models, pain evaluation is necessary to better understand the disease, help design and evaluate therapies, and ensure humane treatment of the animals. Therefore, the main objective of this study was to evaluate pain and pathologic findings in an animal model of moderate Achilles tendinopathy induced by treadmill running. Air puffs, instead of electrical shocks, were used to stimulate running so that pain associated with stimulation would be avoided. Pressure pain sensitivity was evaluated in vivo using a new instrumented plier, whereas spinal cord peptides were analyzed ex vivo with high‐performance liquid chromatography tandem mass spectrometry. Tendon histologic slides were semiquantitatively evaluated, using the Bonar score technique and biomechanical properties, using the traction test. After 8 weeks of treadmill running (2 weeks for adaptation and 6 weeks for the lesion protocol), the protocol was stopped because the air puffs became ineffective to stimulate running. We, nevertheless, observed some histologic changes characteristic of overuse tendinopathy as well as decreased mechanical properties, increased Substance P and dynorphin A peptides but without pressure pain sensitivity. These results suggest that air‐puffs stimulation is sufficient to induce an early stage tendinopathy to study new therapeutic drugs without inducing unnecessary pain. They also indicate that pain‐associated peptides could be related with movement evoked pain and with the sharp breakdown of the running performance. The main objective of this study was to correlate pain and pathologic findings in an animal model of moderate Achilles tendinopathy induced by treadmill running. We observed some histologic changes characteristic of overuse tendinopathy as well as decreased mechanical properties, increased Substance P and dynorphin A peptides but without pressure pain sensitivity.
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Affiliation(s)
- Leila Jafari
- Département de génie mécanique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Pascal Vachon
- Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Francis Beaudry
- Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Eve Langelier
- Département de génie mécanique, Université de Sherbrooke, Sherbrooke, Québec, Canada
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46
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Bell R, Taub P, Cagle P, Flatow EL, Andarawis-Puri N. Development of a mouse model of supraspinatus tendon insertion site healing. J Orthop Res 2015; 33:25-32. [PMID: 25231092 DOI: 10.1002/jor.22727] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 08/08/2014] [Indexed: 02/04/2023]
Abstract
Supraspinatus (SS) tendon tears are common musculoskeletal injuries whose surgical repair exhibits the highest incidence of re-tear of any tendon. Development of therapeutics for improving SS tendon healing is impaired by the lack of a model that allows biological perturbations to identify mechanisms that underlie ineffective healing. The objective of this study was to develop a mouse model of supraspinatus insertion site healing by creating a reproducible SS tendon detachment and surgical repair which can be applied to a wide array of inbred mouse strains and genetic mutants. Anatomical and structural analyses confirmed that the rotator cuff of the mouse is similar to that of human, including the presence of a coracoacromial (CA) arch and an insertion site that exhibits a fibrocartilagenous transition zone. The surgical repair was successfully conducted on seven strains of mice that are commonly used in Orthopaedic Research suggesting that the procedure can be applied to most inbred strains and genetic mutants. The quality of the repair was confirmed with histology through 14 days after surgery in two mouse strains that represent the variation in mouse strains evaluated. The developed mouse model will allow us to investigate mechanisms involved in insertion site healing.
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Affiliation(s)
- Rebecca Bell
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, 10029, New York
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47
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Abstract
Tendinopathy is a debilitating musculoskeletal
condition which can cause significant pain and lead to complete rupture
of the tendon, which often requires surgical repair. Due in part
to the large spectrum of tendon pathologies, these disorders continue
to be a clinical challenge. Animal models are often used in this
field of research as they offer an attractive framework to examine
the cascade of processes that occur throughout both tendon pathology and
repair. This review discusses the structural, mechanical, and biological
changes that occur throughout tendon pathology in animal models,
as well as strategies for the improvement of tendon healing. Cite this article: Bone Joint Res 2014;3:193–202.
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Affiliation(s)
- M W Hast
- University of Pennsylvania, McKay Orthopaedic Research Laboratory, 424 Stemmler Hall 36th Street and Hamilton Walk, Philadelphia, 19104-6081, USA
| | - A Zuskov
- University of Pennsylvania, McKay Orthopaedic Research Laboratory, 424 Stemmler Hall 36th Street and Hamilton Walk, Philadelphia, 19104-6081, USA
| | - L J Soslowsky
- University of Pennsylvania, McKay Orthopaedic Research Laboratory, 424 Stemmler Hall 36th Street and Hamilton Walk, Philadelphia, 19104-6081, USA
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Lenskjold A, Kongsgaard M, Larsen JO, Nielsen RH, Kovanen V, Aagaard P, Kjaer M, Magnusson SP. The influence of physical activity during youth on structural and functional properties of the Achilles tendon. Scand J Med Sci Sports 2013; 25:25-31. [DOI: 10.1111/sms.12143] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2013] [Indexed: 12/22/2022]
Affiliation(s)
- A. Lenskjold
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - M. Kongsgaard
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - J. O. Larsen
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
| | - R. H. Nielsen
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - V. Kovanen
- Gerontology Research Center, Department of Health Sciences; University of Jyväskylä; Jyväskylä Finland
| | - P. Aagaard
- Institute of Sports Exercise and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC); University of Southern Denmark; Odense Denmark
| | - M. Kjaer
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - S. P. Magnusson
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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Schepull T, Aspenberg P. Early controlled tension improves the material properties of healing human achilles tendons after ruptures: a randomized trial. Am J Sports Med 2013; 41:2550-7. [PMID: 24005873 DOI: 10.1177/0363546513501785] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Weightbearing in a fixed brace after acute Achilles tendon ruptures does not necessarily lead to mechanical tension in the tendon. Early motion has a positive effect on the clinical outcome, but it is not clear if this is because of effects on tendon strength or unspecific effects. The aim of this study was to examine if tensional loading leads to an improvement in the mechanical properties of the healing Achilles tendon. HYPOTHESIS The elastic modulus of the tendon callus is increased by early tensional loading. STUDY DESIGN Randomized controlled trial; Level of evidence, 2. METHODS Thirty-five patients with an acute Achilles tendon rupture were recruited consecutively. They underwent surgery with a single suture and received metal markers in the distal and proximal parts of the tendon. After surgery, the patients were randomized to either cast immobilization for 7 weeks or tensional loading. The latter group wore a cast for 2 weeks and then a removable foam walker boot for 5 weeks. They were instructed to remove the boot twice daily and push a special training pedal to produce a predetermined, gradually increasing tensional load on the healing tendon. At 7, 19, and 52 weeks postoperatively, the patients were investigated with roentgen stereophotogrammetric analysis under different loading conditions and computed tomography. The collected data allowed calculation of the modulus of elasticity. At 52 weeks, the clinical outcome was also examined using the Achilles tendon Total Rupture Score (ATRS) and the heel-raise index. RESULTS The elastic modulus at 19 and 52 weeks was higher in the tensional loading group. There was no significant difference in the ATRS or heel-raise index at 52 weeks. As in previous studies, there was a significant correlation between the modulus at 7 weeks and the heel-raise index at 52 weeks. There were no signs of tendon elongation. CONCLUSION Early tensional loading improves the mechanical properties of the healing Achilles tendon.
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Affiliation(s)
- Thorsten Schepull
- Thorsten Schepull, Orthopedics, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, SE 58185 Linköping, Sweden. ;
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50
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Wang L, Huang MJ, Yin GH, Zhang ZM, Jin J, Lai PL, Yan B, Huang B, Bai XC, Jin DD. WITHDRAWN: Characterization of a novel calcific Achilles tendinopathy model in mice: contralateral tendinopathy induced by unilateral tenotomy. J Surg Res 2013. [DOI: 10.1016/j.jss.2013.10.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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