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Zhao R, Han F, Yu Q, Zhu Z, Tu Z, Xia T, Li B. A multifunctional scaffold that promotes the scaffold-tissue interface integration and rescues the ROS microenvironment for repair of annulus fibrosus defects. Bioact Mater 2024; 41:257-270. [PMID: 39149595 PMCID: PMC11325007 DOI: 10.1016/j.bioactmat.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/04/2024] [Accepted: 03/07/2024] [Indexed: 08/17/2024] Open
Abstract
Due to the limited self-repair ability of the annulus fibrosus (AF), current tissue engineering strategies tend to use structurally biomimetic scaffolds for AF defect repair. However, the poor integration between implanted scaffolds and tissue severely affects their therapeutic effects. To solve this issue, we prepared a multifunctional scaffold containing loaded lysyl oxidase (LOX) plasmid DNA exosomes and manganese dioxide nanoparticles (MnO2 NPs). LOX facilitates extracellular matrix (ECM) cross-linking, while MnO2 NPs inhibit excessive reactive oxygen species (ROS)-induced ECM degradation at the injury site, enhancing the crosslinking effect of LOX. Our results revealed that this multifunctional scaffold significantly facilitated the integration between the scaffold and AF tissue. Cells were able to migrate into the scaffold, indicating that the scaffold was not encapsulated as a foreign body by fibrous tissue. The functional scaffold was closely integrated with the tissue, effectively enhancing the mechanical properties, and preventing vascular invasion, which emphasized the importance of scaffold-tissue integration in AF repair.
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Affiliation(s)
- Runze Zhao
- Medical 3D Printing Center, Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, MOE Key Laboratory of Geriatric Diseases and Immunology, School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu, 215000, China
- Center of Translational Medicine and Clinical Laboratory, The Fourth Affiliated Hospital to Soochow University, Suzhou, 215028, China
| | - Feng Han
- Medical 3D Printing Center, Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, MOE Key Laboratory of Geriatric Diseases and Immunology, School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu, 215000, China
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, 210000, China
| | - Qifan Yu
- Medical 3D Printing Center, Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, MOE Key Laboratory of Geriatric Diseases and Immunology, School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu, 215000, China
| | - Zhuang Zhu
- Medical 3D Printing Center, Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, MOE Key Laboratory of Geriatric Diseases and Immunology, School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu, 215000, China
| | - Zhengdong Tu
- Medical 3D Printing Center, Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, MOE Key Laboratory of Geriatric Diseases and Immunology, School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu, 215000, China
- Second Department of Orthopaedics, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou, 215127, China
| | - Tingting Xia
- Institute of Clinical Medicine Research, Suzhou Hospital, Affiliated Hospital of Medical School, Nanjing University, Suzhou, 215153, China
| | - Bin Li
- Medical 3D Printing Center, Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, MOE Key Laboratory of Geriatric Diseases and Immunology, School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu, 215000, China
- Collaborative Innovation Center of Hematology, Soochow University, Suzhou, Jiangsu, 215000, China
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Xiang P, Luo ZP, Che YJ. Insights into the mechanical microenvironment within the cartilaginous endplate: An emerging role in maintaining disc homeostasis and normal function. Heliyon 2024; 10:e31162. [PMID: 38803964 PMCID: PMC11128916 DOI: 10.1016/j.heliyon.2024.e31162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 05/29/2024] Open
Abstract
Biomechanical factors are strongly linked with the emergence and development of intervertebral disc degeneration (IVDD). The intervertebral disc (IVD), as a unique enclosed biomechanical structure, exhibits distinct mechanical properties within its substructures. Damage to the mechanical performance of any substructure can disrupt the overall mechanical function of the IVD. Endplate degeneration serves as a significant precursor to IVDD. The endplate (EP) structure, especially the cartilaginous endplate (CEP), serves as a conduit for nutrient and metabolite transport in the IVD. It is inevitably influenced by its nutritional environment, mechanical loading, cytokines and extracellular components. Currently, reports on strategies targeting the CEP for the prevention and treatment of IVDD are scarce. This is due to two primary reasons: first, limited knowledge of the biomechanical microenvironment surrounding the degenerated CEP cells; and second, innovative biological treatment strategies, such as implanting active cells (disc or mesenchymal stem cells) or modulating natural cell activity through the addition of therapeutic factors or genes to treat IVDD often overlook a critical aspect-the restoration of the nutrient supply function and mechanical microenvironment of the endplate. Therefore, restoring the healthy structure of the CEP and maintaining a stable mechanical microenvironment within the EP are crucial for the prevention of IVDD and the repair of degenerated IVDs. We present a comprehensive literature review on the mechanical microenvironment characteristics of cartilage endplates and their associated mechanical signaling pathways. Our aim is to provide valuable insights into the development and implementation of strategies to prevent IVDD by delaying or reversing CEP degeneration.
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Affiliation(s)
- Pan Xiang
- Department of Orthopaedics, The First Affiliated Hospital of SooChow University, Suzhou, Jiangsu, 215000, PR China
| | - Zong-Ping Luo
- Department of Orthopaedics, The First Affiliated Hospital of SooChow University, Suzhou, Jiangsu, 215000, PR China
| | - Yan-Jun Che
- Orthopedics and Sports Medicine Center, The Affiliated Suzhou Hospital of Nanjing Medical University, 242 Guangji Road, Suzhou, Jiangsu, 215008, PR China
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Jiang T, Tang XY, Mao Y, Zhou YQ, Wang JJ, Li RM, Xie XR, Zhang HM, Fang B, Ouyang NJ, Tang GH. Matrix mechanics regulate the polarization state of bone marrow-derived neutrophils through the JAK1/STAT3 signaling pathway. Acta Biomater 2023; 168:159-173. [PMID: 37467837 DOI: 10.1016/j.actbio.2023.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 07/11/2023] [Accepted: 07/11/2023] [Indexed: 07/21/2023]
Abstract
Matrix mechanics regulate essential cell behaviors through mechanotransduction, and as one of its most important elements, substrate stiffness was reported to regulate cell functions such as viability, communication, migration, and differentiation. Neutrophils (Neus) predominate the early inflammatory response and initiate regeneration. The activation of Neus can be regulated by physical cues; however, the functional alterations of Neus by substrate stiffness remain unknown, which is critical in determining the outcomes of engineered tissue mimics. Herein, a three-dimensional (3D) culture system made of hydrogels was developed to explore the effects of varying stiffnesses (1.5, 2.6, and 5.7 kPa) on the states of Neus. Neus showed better cell integrity and viability in the 3D system. Moreover, it was shown that the stiffer matrix tended to induce Neus toward an anti-inflammatory phenotype (N2) with less adhesion molecule expression, less reactive oxygen species (ROS) production, and more anti-inflammatory cytokine secretion. Additionally, the aortic ring assay indicated that Neus cultured in a stiffer matrix significantly increased vascular sprouting. RNA sequencing showed that a stiffer matrix could significantly activate JAK1/STAT3 signaling in Neus and the inhibition of JAK1 ablated the stiffness-dependent increase in the expression of CD182 (an N2 marker). Taken together, these results demonstrate that a stiffer matrix promotes Neus to shift to the N2 phenotype, which was regulated by JAK1/STAT3 pathway. This study lays the groundwork for further research on fabricating engineered tissue mimics, which may provide more treatment options for ischemic diseases and bone defects. STATEMENT OF SIGNIFICANCE.
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Affiliation(s)
- Ting Jiang
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai 200011, PR China; Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China
| | - Xin-Yue Tang
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai 200011, PR China; Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China
| | - Yi Mao
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai 200011, PR China; Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China
| | - Yu-Qi Zhou
- Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China
| | - Jia-Jia Wang
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai 200011, PR China; Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China
| | - Ruo-Mei Li
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai 200011, PR China; Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China
| | - Xin-Ru Xie
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai 200011, PR China; Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China
| | - Hong-Ming Zhang
- Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China
| | - Bing Fang
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai 200011, PR China; Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China.
| | - Ning-Juan Ouyang
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai 200011, PR China.
| | - Guo-Hua Tang
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai 200011, PR China; Oral Bioengineering Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai 200011, PR China.
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He S, Zhang Y, Zhou Z, Shao X, Chen K, Dai S, Liang T, Qian Z, Luo Z. Similarity and difference between aging and puncture-induced intervertebral disc degeneration. J Orthop Res 2022; 40:2565-2575. [PMID: 35072275 DOI: 10.1002/jor.25281] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 01/10/2022] [Accepted: 01/16/2022] [Indexed: 02/04/2023]
Abstract
The purpose of our study was to investigate the changes in micromorphology and mechanical properties of intervertebral discs degeneration induced by aging and puncture. Normal group (NG), 2 weeks post-puncture degeneration group (PDG) and aging degeneration group (ADG) each included 10 rats. Plain film, magnetic resonance imaging, and histological testing were utilized to assess intervertebral disc degeneration. Atomic force microscope was utilized to analyze the microstructure and elastic modulus of the intervertebral disc, while immunohistochemistry was employed to assess alterations in the cell matrix using collagen I, collagen II, matrix metalloproteinase-3 (MMP-3), and tumour necrosis factor-α (TNF-α). The results showed that the disc height ratio between PDG and ADG decreased. In the PDG and ADG group, histological scores both increased, the gray value of the T2 signal decreased, the proportion of MMP-3 and TNF-positive cells in intervertebral disc tissues was higher (p < 0.05) and the IOD values of COL-2 lower in intervertebral disc tissues (p < 0.05). The elastic modulus of PDG and ADG annulus fibers (AF) increased compared to the NG (p < 0.05); when compared to PDG, the elastic modulus of ADG AF decreased (p < 0.05). The elastic modulus of PDG and ADG collagen increased in the nucleus pulposus (NP, p < 0.05); ADG had a greater AF diameter than NG and PDG (p < 0.05). The results indicated that ADG fiber diameter thickens, and chronic inflammation indicators rise; PDG suffers from severe extracellular matrix loss. The degeneration of the ADG and PDG intervertebral discs is different. The results provide foundation for clinical research.
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Affiliation(s)
- Shuangjun He
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China.,Department of Orthopedic Surgery, Affiliated Danyang Hospital of Nantong University, The People's Hospital of Danyang, Danyang, Jiangsu, China
| | - Yijian Zhang
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Zhangzhe Zhou
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Xiaofeng Shao
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Kangwu Chen
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Shouqian Dai
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Ting Liang
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China.,Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, China
| | - Zhonglai Qian
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Zongping Luo
- Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, China
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5
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Che YJ, Guo JB, Hao YF, Luo ZP. Regenerating and repairing degenerative intervertebral discs by regulating the micro/nano environment of degenerative bony endplates based on low-tension mechanics. BMC Musculoskelet Disord 2022; 23:462. [PMID: 35578221 PMCID: PMC9112526 DOI: 10.1186/s12891-022-05422-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 05/05/2022] [Indexed: 11/10/2022] Open
Abstract
Background Conservative treatment is the recommended first-line treatment for degenerative disc diseases. Traction therapy has historically been one of the most common clinical methods to address this, but the clinical effect remains controversial. Methods Forty-two six-month-old male Sprague-Dawley rats were randomly divided into six groups: the model group (Group A, four coccyx vertebrae (Co7-Co10) were fixed with customized external fixators, and the vertebral disc degeneration model was constructed by axial compression of the target segment Co8 - Co9 for 4 weeks), the experimental control group (Group B, after successful modeling, the external fixation device was removed and self-rehabilitation was performed) and four intervention groups (Groups C to F): Groups C and E: Co8 - Co9 vertebrae compressed for 4 weeks followed by two or 4 weeks of high tension traction (HTT), respectively, and Groups D and F: vertebrae compressed for 4 weeks followed by two or 4 weeks of low-tension traction (LTT), respectively. Imaging tests (X-ray and MRI) were performed to assess disc height and T2 signal intensity at each time point. After the experiment, the animals were euthanized, and the caudal vertebrae were collected for analysis of intervertebral disc histopathology, proteoglycan content, and micronanostructure of the annulus fibrosus, nucleus pulposus and bony endplate. Results Signs of tissue regeneration were apparent in all four intervention groups. After two to 4 weeks of intervention (HTT and LTT), the morphology of pores in the bony endplate, their number, and diameter had recovered significantly compared with those in Group A. The LTT group was superior to the HTT group, and the 4w in situ group was significantly superior to the 2w group. Meanwhile, the histological scores of discs, the mean fibril diameter and modulus of annulus fibrosus were significantly improved compared with the control groups, and the LTT group was superior to HTT group. Conclusions Low-tension traction better promotes active reconstruction of bony endplates and improves the elastic modulus and micro/nanostructure of the disc. Thus, it further promotes the regeneration and repair of intervertebral discs.
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Affiliation(s)
- Yan-Jun Che
- Orthopedics and Sports Medicine Center, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215008, Jiangsu Province, China.
| | - Jiang-Bo Guo
- Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, SuZhou, Jiangsu, 215007, People's Republic of China
| | - Yue Feng Hao
- Orthopedics and Sports Medicine Center, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215008, Jiangsu Province, China
| | - Zong-Ping Luo
- Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, SuZhou, Jiangsu, 215007, People's Republic of China
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Bhattacharya S, Dubey DK. Impact of Variations in Water Concentration on the Nanomechanical Behavior of Type I Collagen Microfibrils in Annulus Fibrosus. J Biomech Eng 2022; 144:1120715. [PMID: 34820681 DOI: 10.1115/1.4052563] [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: 04/04/2021] [Indexed: 11/08/2022]
Abstract
Radial variation in water concentration from outer to inner lamellae is one of the characteristic features of annulus fibrosus (AF). In addition, water concentration changes are also associated with intervertebral disc (IVD) degeneration. Such changes alter the chemo-mechanical interactions among the biomolecular constituents at molecular level, affecting the load-bearing nature of IVD. This study investigates mechanistic impacts of water concentration on the collagen type I microfibrils in AF using molecular dynamics simulations. Results show, in axial tension, that increase in water concentration (WC) from 0% to 50% increases the elastic modulus from 2.7 GPa to 3.9 GPa. This is attributed to combination of shift in deformation from backbone straightening to combined backbone stretching- intermolecular sliding and subsequent strengthening of tropocollagen-water (TC-water-TC) interfaces through water bridges and intermolecular electrostatic attractions. Further increase in WC to 75% reduces the modulus to 1.8 GPa due to shift in deformation to polypeptide straightening and weakening of TC-water-TC interface due to reduced electrostatic attraction and increase in the number of water molecules in a water bridge. During axial compression, increase in WC to 50% results in increase in modulus from 0.8 GPa to 4.5 GPa. This is attributed to the combination of the development of hydrostatic pressure and strengthening of the TC-water-TC interface. Further increase in WC to 75% shifts load-bearing characteristic from collagen to water, resulting in a decrease in elastic modulus to 2.8 GPa. Such water-mediated alteration in load-bearing properties acts as foundations toward AF mechanics and provides insights toward understanding degeneration-mediated altered spinal stiffness.
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Affiliation(s)
- Shambo Bhattacharya
- Department of Mechanical Engineering, Indian Institute of Technology, Delhi, New Delhi 110016, India
| | - Devendra K Dubey
- Department of Mechanical Engineering, Indian Institute of Technology, Delhi, New Delhi 110016, India
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Tavakoli J, Geargeflia S, Tipper JL, Diwan AD. Magnetic resonance elastography: A non-invasive biomarker for low back pain studies. BIOMEDICAL ENGINEERING ADVANCES 2021. [DOI: 10.1016/j.bea.2021.100014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Yu ZH, Ji YC, Li K, Liang T, Liu B, Chen HL, Ni L, Luo ZP, Yang HL. Stiffness of the extracellular matrix affects apoptosis of nucleus pulposus cells by regulating the cytoskeleton and activating the TRPV2 channel protein. Cell Signal 2021; 84:110005. [PMID: 33862152 DOI: 10.1016/j.cellsig.2021.110005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/26/2021] [Accepted: 04/05/2021] [Indexed: 11/26/2022]
Abstract
It is known that nucleus pulposus cells (NPs) play an important role in intervertebral disc degeneration (IVDD), and a previous study indicated that the stiffness of NP tissue changes during the degeneration process. However, the mechanism underlying the cellular response to ECM stiffness is still unclear. To analyze the effects of extracellular matrix (ECM) with different degrees of stiffness on NPs, we prepared polyacrylamide (PA) gels with different elastic moduli, and cells grown under different stiffness conditions were obtained and analyzed. The results showed that the spreading morphology of NPs changed significantly under increased ECM elastic modulus conditions and that TRPV2 and the PI3K / AKT signaling pathway were activated by stiffer ECM. At the same time, mitochondria released cytochrome c (Cyt c) and activated caspase proteins to promote the apoptosis of NPs. After TRPV2 was specifically knocked out, the activation of the PI3K / AKT signaling pathway decreased, and the release of Cyt c and NP apoptosis were reduced. These results indicate that TRPV2 is closely linked to the detection of extracellular mechanical signals, and that conversion of mechanical and biological signals plays an important role in regulating the biological behavior of cells. This study offers a new perspective on the cellular and biochemical events underlying IVDD which could result in novel treatments.
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Affiliation(s)
- Zhao-Hui Yu
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China; Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
| | - Yi-Chao Ji
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China; Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
| | - Kun Li
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Ting Liang
- Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
| | - Bo Liu
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China; Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
| | - Hai-Lei Chen
- Department of Neurosurgery, Jiangsu Rudong County People's Hospital, Nantong City, Jiangsu Province, China
| | - Li Ni
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China; Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China.
| | - Zong-Ping Luo
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China; Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China.
| | - Hui-Lin Yang
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China; Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China.
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9
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Xu H, Liang T, Wei L, Zhu JC, Liu X, Ji CC, Liu B, Luo ZP. Nano-elastic modulus of tendon measured directly in living mice. J Biomech 2021; 116:110248. [PMID: 33485146 DOI: 10.1016/j.jbiomech.2021.110248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/23/2020] [Accepted: 01/03/2021] [Indexed: 01/16/2023]
Abstract
The nano-biomechanical environment of the extracellular matrix is critical for cells to sense and respond to mechanical loading. However, to date, this important characteristic remains poorly understood in living tissue structures. This study reports the experimental measurement of the in vivo nano-elastic modulus of the tendon in a mouse tail model. The experiment was performed on the tail tendon of an 8-week-old C57BL/6 live mouse. Mechanical loading on tail tendons was regulated by changing both voltage and frequency of alternating current stimulation on the erector spinae. The nano-elastic modulus of the tail tendon was measured by atomic force microscope. The nano-elastic modulus showed significant variation (2.19-35.70 MPa) between different locations and up to 39% decrease under muscle contraction, suggesting a complicated biomechanical environment in which cells dwell. In addition, the nano-elastic modulus of the tail tendon measured in live mice was significantly lower than that measured in vitro, suggesting a disagreement of tissue mechanical properties in vivo and in vitro. This information is important for the designs of new extracellular biomaterial that can better mimic the biological environment, and improve clinical outcomes of musculoskeletal tissue degenerations and associated disorders.
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Affiliation(s)
- Hao Xu
- Orthopedic Institute, Medical College, Soochow University, Suzhou, PR China; Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Ting Liang
- Orthopedic Institute, Medical College, Soochow University, Suzhou, PR China; Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Liangyi Wei
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Jun-Cheng Zhu
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Xuhui Liu
- San Francisco Veterans Affairs Health Care System, and Department of Orthopedic Surgery, University of California at San Francisco, 1700 Owens Street, Room 364, San Francisco, CA 94158, USA
| | - Chen-Chen Ji
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Bo Liu
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Zong-Ping Luo
- Orthopedic Institute, Medical College, Soochow University, Suzhou, PR China; Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China.
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10
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Che YJ, Hou JJ, Guo JB, Liang T, Zhang W, Lu Y, Yang HL, Hao YF, Luo ZP. Low energy extracorporeal shock wave therapy combined with low tension traction can better reshape the microenvironment in degenerated intervertebral disc regeneration and repair. Spine J 2021; 21:160-177. [PMID: 32800896 DOI: 10.1016/j.spinee.2020.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/07/2020] [Accepted: 08/07/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Low-tension traction is more effective than high-tension traction in restoring the height and rehydration of a degenerated disc and to some extent the bony endplate. This might better reshape the microenvironment for disc regeneration and repair. However, the repair of the combination of endplate sclerosis, osteophyte formation, and even collapse leading to partial or nearly complete occlusion of the nutrient channel is greatly limited. PURPOSE To evaluate the effectiveness of low-intensity extracorporeal shock wave therapy (ESWT) combined with low tension traction for regeneration and repair of moderately and severely degenerated discs; to explore the possible mechanism of action. STUDY DESIGN Animal study of a rat model of degenerated discs. METHODS A total of thirty-five 6-month old male Sprague-Dawley rats were randomly assigned to one of five groups (n=7, each group). In Group A (model group), caudal vertebrae were immobilized using a custom-made external device to fix four caudal vertebrae (Co7-Co10) whereas Co8-Co9 underwent 4 weeks of compression to induce moderate disc degeneration. In Group B (experimental control group), as in Group A, disc degeneration was successfully induced after which the fixed device was removed for 8 weeks of self-recovery. The remaining three groups of rats represented the intervention Groups (C-E): after successful generation of disc degeneration in Group C (com - 4w/tra - 4w) and Group D (com - 4w/ESWT), as described for group A, low-tension traction (in-situ traction) or low-energy ESWT was administered for 4 weeks (ESWT parameters: intensity: 0.15 Mpa; frequency: 1 Hz; impact: 1,000 each time; once/week, 4 times in total); Group E (com - 4w/tra - 4w/ESWT): disc degeneration as described for group A, low-tension traction combined with low-energy ESWT was conducted (ESWT parameters as Group D). After experimentation, caudal vertebrae were harvested and disc height, T2 signal intensity, disc morphology, total glycosaminoglycan (GAG) content, gene expression, structure of the Co8-Co9 bony endplates and elastic moduli of the discs were measured. RESULTS After continuous low-tension traction, low energy ESWT intervention or combined intervention, the degenerated discs effectively recovered their height and became rehydrated. However, the response in Group D was weaker than in the other intervention groups in terms of restoration of intervertebral disc (IVD) height, whereas Group E was superior in disc rehydration. Tissue regeneration was evident in Groups C to E using different interventions. No apparent tissue regeneration was observed in the experimental control group (Group B). The histological scores of the three intervention groups (Groups C-E) were lower than those of Groups A or B (p<.0001), and the scores of Groups C and E were significantly lower than those of Group D (p<.05), but not Group C versus Group E (p>.05). Compared with the intervention groups (Groups C-E), total GAG content of the nucleus pulposus (NP) in Group B did not increase significantly (p>.05). There was also no significant difference in the total GAG content between Groups A and B (p>.05). Of the three intervention groups, the recovery of NP GAG content was greatest in Group E. The expression of collagen I and II, and aggrecan in the annulus fibrosus (AF) was up-regulated (p<.05), whereas the expression of MMP-3, MMP-13, and ADAMTS-4 was down-regulated (p<.05). Of the groups, Group E displayed the greatest degree of regulation. The trend in regulation of gene expression in the NP was essentially consistent with that of the AF, of which Group E was the greatest. In the intervention groups (Groups C-E), compared with Group A, the pore structure of the bony endplate displayed clear changes. The number of pores in the endplate in Groups C to E was significantly higher than in Group A (p<.0001), among which Group C versus Group D (p=.9724), and Group C versus Group E (p=.0116). There was no significant difference between Groups A and B (p=.5261). In addition, the pore diameter also increased, the trend essentially the same as that of pore density. There was no significant difference between the three intervention groups (p=.7213). It is worth noting that, compared with Groups A and B, peripheral pore density and size in Groups D and E of the three intervention groups recovered significantly. The elastic modulus and diameter of collagen fibers in the AF and NP varied with the type of intervention. Low tension traction combined with ESWT resulted in the greatest impact on the diameter and modulus of collagen fibers. CONCLUSIONS Low energy ESWT combined with low tension traction provided a more stable intervertebral environment for the regeneration and repair of moderate and severe degenerative discs. Low energy ESWT promoted the regeneration of disc matrix by reducing MMP-3, MMP-13, and ADAMTS-4 resulting in inhibition of collagen degradation. Although axial traction promoted the recovery of height and rehydration of the IVD, combined with low energy ESWT, the micro-nano structure of the bony endplate underwent positive reconstruction, tension in the annulus of the AF and nuclear stress of the NP declined, and the biomechanical microenvironment required for IVD regeneration and repair was reshaped.
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Affiliation(s)
- Yan-Jun Che
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, Suzhou, Jiangsu 215007, People's Republic of China; Department of Orthopedics, Heping Hospital Affiliated to Changzhi Medical College, Changzhi, Shanxi, People's Republic of China
| | - Jun-Jun Hou
- Department of Geriatrics, Xinghu Hospital, SuZhou industrial park, Suzhou, Jiangsu, People's Republic of China; Department of Endocrinology, The First Affiliated Hospital of SooChow University, Suzhou, Jiangsu, People's Republic of China
| | - Jiang-Bo Guo
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, Suzhou, Jiangsu 215007, People's Republic of China
| | - Ting Liang
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, Suzhou, Jiangsu 215007, People's Republic of China
| | - Wen Zhang
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, Suzhou, Jiangsu 215007, People's Republic of China
| | - Yan Lu
- Department of Endocrinology, The First Affiliated Hospital of SooChow University, Suzhou, Jiangsu, People's Republic of China
| | - Hui-Lin Yang
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, Suzhou, Jiangsu 215007, People's Republic of China
| | - Yue Feng Hao
- Orthopedics and Sports medicine center, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou 215000, Jiangsu, People's Republic of China
| | - Zong-Ping Luo
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, Suzhou, Jiangsu 215007, People's Republic of China.
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Dai S, Liang T, Fujii T, He S, Zhang F, Jiang H, Liu B, Shi X, Luo Z, Yang H. Increased elastic modulus of the synovial membrane in a rat ACLT model of osteoarthritis revealed by atomic force microscopy. Braz J Med Biol Res 2020; 53:e10058. [PMID: 33053109 PMCID: PMC7552902 DOI: 10.1590/1414-431x202010058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 07/22/2020] [Indexed: 11/21/2022] Open
Abstract
This study aimed to explore changes in nanoscale elastic modulus of the synovium using atomic force microscopy (AFM) in addition to investigate changes in synovial histomorphology and secretory function in osteoarthritis (OA) in a rat anterior cruciate ligament transection (ACLT) model. Sprague-Dawley rats were randomly assigned to sham control and ACLT OA groups. All right knee joints were harvested at 4, 8, or 12 weeks (W) after surgery for histological assessment of cartilage damage and synovitis in both the anterior and posterior capsules. AFM imaging and nanoscale biomechanical testing were conducted to measure the elastic modulus of the synovial collagen fibrils. Immunohistochemistry was used to visualize the expression of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and matrix metalloproteinase-3 (MMP-3) in the synovium. The OA groups exhibited progressive development of disease in the cartilage and synovium. Histopathological scores of the synovium in the OA groups increased gradually. Significant differences were observed between all OA groups except for the posterior 4W group. The synovial fibril arrangement in all OA groups was significantly disordered. The synovial fibrils in all ACLT OA groups at each time point were stiffer than those in the sham controls. OA rats displayed a significantly higher expression of IL-1β and MMP3 in the anterior capsule. In summary, synovial stiffening was closely associated with joint degeneration and might be a factor contributing to synovitis and increased production of proinflammatory mediators. Our data provided insights into the role of synovitis, particularly stiffening of the synovium, in OA pathogenesis.
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Affiliation(s)
- Shouqian Dai
- Orthopedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China.,Department of Emergency Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Ting Liang
- Orthopedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Tadashi Fujii
- Department of Orthopaedic Surgery, Kashiba Asahigaoka Hospital, Kashiba, Nara, Japan
| | - Shuangjun He
- Orthopedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Fan Zhang
- Orthopedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Huaye Jiang
- Orthopedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Bo Liu
- Orthopedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Xiu Shi
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Zongping Luo
- Orthopedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Huilin Yang
- Orthopedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
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Stable mechanical environments created by a low-tension traction device is beneficial for the regeneration and repair of degenerated intervertebral discs. Spine J 2020; 20:1503-1516. [PMID: 32305426 DOI: 10.1016/j.spinee.2020.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND By blocking the cascade of reactions leading to intervertebral disc degeneration through immobilization-traction, a delay in intervertebral disc degeneration and its regeneration, to some extent, has been observed. However, the precise balance of regulation of the microenvironment of intervertebral disc biomechanics and coordination of the complex spatiotemporal reconstruction of the extracellular matrix have not yet been solved, and clinical results are far from successful. PURPOSE In the present study, a mechanical degeneration model was constructed to evaluate the possibility and effectiveness of disc regeneration or repair through low-tension traction of degenerated discs so as to provide basic biomechanical information for clinical optimization of the traction device and to establish traction parameters for prevention and treatment of disc degeneration. STUDY DESIGN A macro-, micro-, and nano-level structural analysis of degenerative discs of rat tail before and after controlled traction. METHODS Six-month-old male Sprague-Dawley rats were randomly divided into seven groups: Group A: control group (instrumented with Kirschner [K]-wires only); Group B: Model group (caudal vertebrae immobilized using a custom-made external device to fix four caudal vertebrae [Co7-Co10], while Co8-Co9 vertebrae underwent 4 weeks of compression to induce disc degeneration); Group C: experimental control group (devices removed after the 4 week compression described in Group B, and recovered by themselves for 4 weeks). The remaining four groups represented intervention groups (Groups D and F: Co8-Co9 vertebrae compressed for 4 weeks followed by 2 or 4 weeks of in situ traction, respectively; Groups E and G: vertebrae compressed for 4 weeks followed by 2 or 4 weeks of excessive traction, respectively). X-ray and magnetic resonance imaging were performed at each time point to measure disc height and T2 signal intensity. At the end of the experiment, the animals were euthanized and tail vertebrae harvested for analysis of intervertebral disc histopathology, proteoglycan content, elastic modulus of fibers of the annulus fibrosus (AF) and nucleus pulposus (NP), and microstructure of the bony end plate. RESULTS After 2 to 4 weeks of continuous traction (in situ and excessive traction), the Co8-Co9 intervertebral disc space of rats in Groups D to G increased significantly compared with Groups B and C (p < .05). In addition, signs of tissue regeneration were apparent in all four intervention groups (D-G). In addition, histologic scores of the intervention groups (D-G) were significantly lower than those in the model and experimental control groups (Groups B and C, respectively), although no significant difference was found between those four groups. Compared with the model group (Group B), total proteoglycan content of the NP in the intervention groups (D-G) increased significantly (p < .05). After 2 to 4 weeks of intervention (in situ and excessive traction), the morphology of pores in the bony end plate, their number, and the diameter had recovered significantly compared with those in Group B. The in situ traction group was superior to the excessive traction group, and 4 weeks in situ group significantly superior to the 2 weeks group. In all intervention groups, in both the inner and outer AF, mean fibril diameter decreased significantly (p < .05), although they remained larger in the excessive traction group than that in the in situ traction group. Consistent with trend in collagen fiber diameter, the outer AF was stiffer than the inner, and the modulus of the AF in each intervention group not significantly different from that of the control group (Group A) except Group C. However, within the NP, the variation in trend in diameter and modulus of collagen fibers was essentially inconsistent with that of the AF. CONCLUSIONS Degenerated discs exhibit greater reconstruction after low tension traction. It is clear that the intervertebral disc mechanical microenvironment depends to a greater extent on low-tension traction than high-tension traction.
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Guo JB, Liang T, Che YJ, Yang HL, Luo ZP. Structure and mechanical properties of high-weight-bearing and low-weight-bearing areas of hip cartilage at the micro- and nano-levels. BMC Musculoskelet Disord 2020; 21:425. [PMID: 32616028 PMCID: PMC7333404 DOI: 10.1186/s12891-020-03468-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 06/29/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Articular cartilage has a high-weight-bearing area and a low-weight-bearing area, the macroscopic elastic moduli of the two regions are different. Chondrocytes are affected by the applied force at the microscopic level. Currently, the modulus of the two areas at the micro and nano levels is unknown, and studies on the relationship between macro-, micro- and nano-scale elastic moduli are limited. Such information may be important for further understanding of cartilage mechanics. Moreover, the surface morphology, proteoglycan content, and micro and nano structure of the two areas, which influences the mechanical properties of cartilage should be discussed. METHODS Safranin-O/Fast Green staining was used to evaluate the surface morphology and semi-quantify proteoglycan content of porcine femoral head cartilage between the two weight-bearing areas. The unconfined compression test was used to determine the macro elastic modulus. Atomic force microscope was used to measure the micro and nano compressive elastic modulus as well as the nano structure. Scanning electron microscope was employed to evaluate the micro structure. RESULTS No significant differences in the fibrillation index were observed between two areas (P = 0.5512). The Safranin-O index of the high-weight-bearing area was significantly higher than that of the low-weight-bearing area (P = 0.0387). The compressive elastic modulus of the high-weight-bearing area at the macro and micro level was significantly higher than that of the low-weight-bearing area (P = 0.0411 for macro-scale, and P = 0.0001 for micro-scale), while no statistically significant differences were observed in the elastic modulus of collagen fibrils at the nano level (P = 0.8544). The density of the collagen fibers was significantly lower in the high-weight-bearing area (P = 0.0177). No significant differences were observed in the structure and diameter of the collagen fibers between the two areas (P = 0.7361). CONCLUSIONS A higher proteoglycan content correlated with a higher compressive elastic modulus of the high-weight-bearing area at the micro level than that of the low-weight-bearing area, which was consistent with the trend observed from the macroscopic compressive elastic modulus. The weight-bearing level was not associated with the elastic modulus of individual collagen fibers and the diameter at the nano level. The micro structure of cartilage may influence the macro- and micro-scale elastic modulus.
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Affiliation(s)
- Jiang-Bo Guo
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China.,Department of Orthopaedics, Orthopaedic Institute, the First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China
| | - Ting Liang
- Department of Orthopaedics, Orthopaedic Institute, the First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China
| | - Yan-Jun Che
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China.,Department of Orthopaedics, Orthopaedic Institute, the First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China
| | - Hui-Lin Yang
- Department of Orthopaedics, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China.,Department of Orthopaedics, Orthopaedic Institute, the First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China
| | - Zong-Ping Luo
- Department of Orthopaedics, Orthopaedic Institute, the First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China.
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Gullbrand SE, Kim DH, Ashinsky BG, Bonnevie ED, Smith HE, Mauck RL. Restoration of physiologic loading modulates engineered intervertebral disc structure and function in an in vivo model. JOR Spine 2020; 3:e1086. [PMID: 32613161 PMCID: PMC7323465 DOI: 10.1002/jsp2.1086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 12/12/2022] Open
Abstract
Tissue-engineered whole disc replacements are an emerging treatment strategy for advanced intervertebral disc degeneration. A challenge facing the translation of tissue-engineered disc replacement to clinical use are the opposing needs of initial immobilization to advantage integration contrasted with physiologic loading and its anabolic effects. Here, we utilize our established rat tail model of tissue engineered disc replacement with external fixation to study the effects of remobilization at two time points postimplantation on engineered disc structure, composition, and function. Our results suggest that the restoration of mechanical loading following immobilization enhanced collagen and proteoglycan content within the nucleus pulposus and annulus fibrosus of the engineered discs, in addition to improving the integration of the endplate region of the construct with native bone. Despite these benefits, angulation of the vertebral bodies at the implanted level occurred following remobilization at both early and late time points, reducing tensile failure properties in the remobilized groups compared to the fixed group. These results demonstrate the necessity of restoring physiologic mechanical loading to engineered disc implants in vivo, and the need to transition toward their evaluation in larger animal models with more human-like anatomy and motion compared to the rat tail.
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Affiliation(s)
- Sarah E. Gullbrand
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz VA Medical CenterPhiladelphiaPennsylvaniaUSA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Dong Hwa Kim
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz VA Medical CenterPhiladelphiaPennsylvaniaUSA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Beth G. Ashinsky
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz VA Medical CenterPhiladelphiaPennsylvaniaUSA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- School of Biomedical Engineering, Science and Health SystemsDrexel UniversityPhiladelphiaPennsylvaniaUSA
| | - Edward D. Bonnevie
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz VA Medical CenterPhiladelphiaPennsylvaniaUSA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Harvey E. Smith
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz VA Medical CenterPhiladelphiaPennsylvaniaUSA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Robert L. Mauck
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz VA Medical CenterPhiladelphiaPennsylvaniaUSA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
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Nano and micro biomechanical analyses of the nucleus pulposus after in situ immobilization in rats. Micron 2020; 130:102824. [PMID: 31927410 DOI: 10.1016/j.micron.2020.102824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/20/2019] [Accepted: 01/03/2020] [Indexed: 01/07/2023]
Abstract
Immobilization can lead to intervertebral disc degeneration. The biomechanical characteristics of such discs have not so far been investigated at the micro- or nanoscale, the level at which cells sense and respond to the surrounding environment. This study aimed to characterize changes in the elastic modulus of the collagen fibrils in the nucleus pulposus at the nanoscale and correlate this with micro-biomechanical properties of the nucleus pulposus after immobilization, in addition to observation of tissue histology and its gene expressions. An immobilization system was used on the rat tail with an external fixation device. The elastic modulus was measured using both nano and micro probes for atomic force microscopy after 4 and 8 weeks of immobilization. Histology of the tissue was observed following hematoxylin and eosin staining. Gene expression in the annulus fibrosus tissue was quantified using real-time reverse transcription-polymerase chain reaction. The elastic modulus of the collagen fibrils in the nucleus pulposus at the nanoscale increased from 74.07 ± 17.06 MPa in the control to 90.06 ± 25.51 MPa after 8 weeks (P = 0.007), and from 33.51 ± 9.33 kPa to 43.18 ± 12.08 kPa at the microscale (P = 0.002). After immobilization for 8 weeks, a greater number of cells were observed by histology to be aggregated within the nucleus pulposus. Collagen II (P = 0.007) and aggrecan (P = 0.003) gene expression were downregulated whereas collagen I (P = 0.002), MMP-3 (P < 0.001), MMP-13 (P < 0.001) and ADAMTs-4 (P < 0.001) were upregulated. Immobilization not only influenced individual collagen fibrils at the nanoscale, but also altered the micro-biomechanics and cell response in the nucleus pulposus. These results suggest that significant changes occur in intervertebral discs at both scales after immobilization, a situation about which clinicians should be aware when immobilization has to be used clinically.
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