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Lillyman DJ, Barnett EC, Miller TJ, Wachs RA. Application of microcomputed tomography to calculate rat intervertebral disc volume as a surrogate measure of degeneration. COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING: IMAGING & VISUALIZATION 2023. [DOI: 10.1080/21681163.2023.2182607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- David J. Lillyman
- Department of Biological Systems Engineering, University of Nebraska, Lincoln, Nebraska, USA
| | - Evie C. Barnett
- Department of Biological Systems Engineering, University of Nebraska, Lincoln, Nebraska, USA
| | - Tyler J. Miller
- Department of Biological Systems Engineering, University of Nebraska, Lincoln, Nebraska, USA
| | - Rebecca A. Wachs
- Department of Biological Systems Engineering, University of Nebraska, Lincoln, Nebraska, USA
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2
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Easson GWD, Savadipour A, Anandarajah A, Iannucci LE, Lake SP, Guilak F, Tang SY. Modulation of TRPV4 protects against degeneration induced by sustained loading and promotes matrix synthesis in the intervertebral disc. FASEB J 2023; 37:e22714. [PMID: 36583692 DOI: 10.1096/fj.202201388r] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/15/2022] [Accepted: 12/05/2022] [Indexed: 12/31/2022]
Abstract
While it is well known that mechanical signals can either promote or disrupt intervertebral disc (IVD) homeostasis, the molecular mechanisms for transducing mechanical stimuli are not fully understood. The transient receptor potential vanilloid 4 (TRPV4) ion channel activated in isolated IVD cells initiates extracellular matrix (ECM) gene expression, while TRPV4 ablation reduces cytokine production in response to circumferential stretching. However, the role of TRPV4 on ECM maintenance during tissue-level mechanical loading remains unknown. Using an organ culture model, we modulated TRPV4 function over both short- (hours) and long-term (days) and evaluated the IVDs' response. Activating TRPV4 with the agonist GSK101 resulted in a Ca2+ flux propagating across the cells within the IVD. Nuclear factor (NF)-κB signaling in the IVD peaked at 6 h following TRPV4 activation that subsequently resulted in higher interleukin (IL)-6 production at 7 days. These cellular responses were concomitant with the accumulation of glycosaminoglycans and increased hydration in the nucleus pulposus that culminated in higher stiffness of the IVD. Sustained compressive loading of the IVD resulted in elevated NF-κB activity, IL-6 and vascular endothelial growth factor A (VEGFA) production, and degenerative changes to the ECM. TRPV4 inhibition using GSK205 during loading mitigated the changes in inflammatory cytokines, protected against IVD degeneration, but could not prevent ECM disorganization due to mechanical damage in the annulus fibrosus. These results indicate TRPV4 plays an important role in both short- and long-term adaptations of the IVD to mechanical loading. The modulation of TRPV4 may be a possible therapeutic for preventing load-induced IVD degeneration.
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Affiliation(s)
- Garrett W D Easson
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Alireza Savadipour
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA.,Shriner's Hospital for Children - St. Louis, St. Louis, Missouri, USA
| | - Akila Anandarajah
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Leanne E Iannucci
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Spencer P Lake
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Farshid Guilak
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA.,Shriner's Hospital for Children - St. Louis, St. Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Simon Y Tang
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
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3
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Contrast-enhanced microCT evaluation of degeneration following partial and full width injuries to the mouse lumbar intervertebral disc. Sci Rep 2022; 12:15555. [PMID: 36114343 PMCID: PMC9481554 DOI: 10.1038/s41598-022-19487-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
A targeted injury to the mouse intervertebral disc (IVD) is often used to recapitulate the degenerative cascade of the human pathology. Since injuries can vary in magnitude and localization, it is critical to examine the effects of different injuries on IVD degeneration. We thus evaluated the degenerative progression resulting from either a partial- or full-width injury to the mouse lumbar IVD using contrast-enhanced micro-computed tomography and histological analyses. A lateral-retroperitoneal surgical approach was used to access the lumbar IVD, and the injuries to the IVD were produced by either incising one side of the annulus fibrosus or puncturing both sides of the annulus fibrosus. Female C57BL/6J mice of 3–4 months age were used in this study. They were divided into three groups to undergo partial-width, full-width, or sham injuries. The L5/6 and L6/S1 lumbar IVDs were surgically exposed, and then the L6/S1 IVDs were injured using either a surgical scalpel (partial-width) or a 33G needle (full-width), with the L5/6 serving as an internal control. These animals recovered and then euthanized at either 2-, 4-, or 8-weeks after surgery for evaluation. The IVDs were assessed for degeneration using contrast-enhanced microCT (CEµCT) and histological analysis. The high-resolution 3D CEµCT evaluation of the IVD confirmed that the respective injuries were localized within one side of the annulus fibrosus or spanned the full width of the IVD. The full-width injury caused significant deteriorations in the nucleus pulposus, annulus fibrous and at the interfaces after 2 weeks, which was sustained through the 8 weeks, while the partial width injury caused localized disruptions that remained limited to the annulus fibrosus. The use of CEµCT revealed distinct IVD degeneration profiles resulting from partial- and full-width injuries. The partial width injury may serve as an alternative model for IVD degeneration resulting from localized annulus fibrosus injuries.
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High Resolution Micro-Computed Tomography Reveals a Network of Collagen Channels in the Body Region of the Knee Meniscus. Ann Biomed Eng 2021; 49:2273-2281. [PMID: 33829363 PMCID: PMC8455383 DOI: 10.1007/s10439-021-02763-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/01/2021] [Indexed: 02/08/2023]
Abstract
The meniscus is an integral part of the human knee, preventing joint degradation by distributing load from the femoral condyles to the tibial plateau. Recent qualitative studies suggested that the meniscus is constituted by an intricate net of collagen channels inside which the fluid flows during loading. The aim of this study is to describe in detail the structure in which this fluid flows by quantifying the orientation and morphology of the collagen channels of the meniscal tissue. A 7 mm cylindrical sample, extracted vertically from the central part of a lateral porcine meniscus was freeze-dried and scanned using the highest-to-date resolution Microscopic Computed Tomography. The orientation of the collagen channels, their size and distribution was calculated. Comparisons with confocal multi-photon microscopy imaging performed on portions of fresh tissue have shown that the freeze-dried procedure adopted here ensures that the native architecture of the tissue is maintained. Sections of the probe at different heights were examined to determine differences in composition and structure along the sample from the superficial to the internal layers. Results reveal a different arrangement of the collagen channels in the superficial layers with respect to the internal layers with the internal layers showing a more ordered structure of the channels oriented at 30[Formula: see text] with respect to the vertical, a porosity of 66.28% and the mean size of the channels of 22.14 [Formula: see text].
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Contrast enhanced computed tomography for real-time quantification of glycosaminoglycans in cartilage tissue engineered constructs. Acta Biomater 2019; 100:202-212. [PMID: 31580960 DOI: 10.1016/j.actbio.2019.09.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 09/06/2019] [Accepted: 09/11/2019] [Indexed: 12/14/2022]
Abstract
Tissue engineering and regenerative medicine are two therapeutic strategies to treat, and to potentially cure, diseases affecting cartilaginous tissues, such as osteoarthritis and cartilage defects. Insights into the processes occurring during regeneration are essential to steer and inform development of the envisaged regenerative strategy, however tools are needed for longitudinal and quantitative monitoring of cartilage matrix components. In this study, we introduce a contrast-enhanced computed tomography (CECT)-based method using a cationic iodinated contrast agent (CA4+) for longitudinal quantification of glycosaminoglycans (GAG) in cartilage-engineered constructs. CA4+ concentration and scanning protocols were first optimized to ensure no cytotoxicity and a facile procedure with minimal radiation dose. Chondrocyte and mesenchymal stem cell pellets, containing different GAG content were generated and exposed to CA4+. The CA4+ content in the pellets, as determined by micro computed tomography, was plotted against GAG content, as measured by 1,9-dimethylmethylene blue analysis, and showed a high linear correlation. The established equation was used for longitudinal measurements of GAG content over 28 days of pellet culture. Importantly, this method did not adversely affect cell viability or chondrogenesis. Additionally, the CA4+ distribution accurately matched safranin-O staining on histological sections. Hence, we show proof-of-concept for the application of CECT, utilizing a positively charged contrast agent, for longitudinal and quantitative imaging of GAG distribution in cartilage tissue-engineered constructs. STATEMENT OF SIGNIFICANCE: Tissue engineering and regenerative medicine are promising therapeutic strategies for different joint pathologies such as cartilage defects or osteoarthritis. Currently, in vitro assessment on the quality and composition of the engineered cartilage mainly relies on destructive methods. Therefore, there is a need for the development of techniques that allow for longitudinal and quantitative imaging and monitoring of cartilage-engineered constructs. This work harnesses the electrostatic interactions between the negatively-charged glycosaminoglycans (GAGs) and a positively-charged contrast agent for longitudinal and non-destructive quantification of GAGs, providing valuable insight on GAG development and distribution in cartilage engineered constructs. Such technique can advance the development of regenerative strategies, not only by allowing continuous monitoring but also by serving as a pre-implantation screening tool.
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Liu Z, Easson GWD, Zhao J, Makki N, Ahituv N, Hilton MJ, Tang SY, Gray RS. Dysregulation of STAT3 signaling is associated with endplate-oriented herniations of the intervertebral disc in Adgrg6 mutant mice. PLoS Genet 2019; 15:e1008096. [PMID: 31652254 PMCID: PMC6834287 DOI: 10.1371/journal.pgen.1008096] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 11/06/2019] [Accepted: 09/18/2019] [Indexed: 12/01/2022] Open
Abstract
Degenerative changes of the intervertebral disc (IVD) are a leading cause of disability affecting humans worldwide and has been attributed primarily to trauma and the accumulation of pathology during aging. While genetic defects have also been associated with disc degeneration, the precise mechanisms driving the initiation and progression of disease have remained elusive due to a paucity of genetic animal models. Here, we discuss a novel conditional mouse genetic model of endplate-oriented disc herniations in adult mice. Using conditional mouse genetics, we show increased mechanical stiffness and reveal dysregulation of typical gene expression profiles of the IVD in adhesion G-protein coupled receptor G6 (Adgrg6) mutant mice prior to the onset of endplate-oriented disc herniations in adult mice. We observed increased STAT3 activation prior to IVD defects and go on to demonstrate that treatment of Adgrg6 conditional mutant mice with a small molecule inhibitor of STAT3 activation ameliorates endplate-oriented herniations. These findings establish ADGRG6 and STAT3 as novel regulators of IVD endplate and growth plate integrity in the mouse, and implicate ADGRG6/STAT3 signaling as promising therapeutic targets for endplate-oriented disc degeneration. Back pain is a leading cause of disability in humans worldwide and one of the most common culprits of these issues are the consequence of degenerative changes of the intervertebral disc. Here, we demonstrate that conditional loss of the Adgrg6 gene in cartilaginous tissues of the spine results in endplate-oriented disc herniations and degenerative changes of the intervertebral disc in mice. We further establish that these obvious degenerative changes of the disc are preceded by substantial alterations in normal gene expression profiles, including upregulation of pro-inflammatory STAT3 signaling, and increased mechanical stiffness of the intervertebral disc. Increased STAT3 activation is a signal observed in other models of degenerative musculoskeletal tissues. As such, we tested whether systemic treatment with a small-molecule STAT3 inhibitor would protect against the formation of endplate-oriented disc herniations in conditional Adgrg6 mutant mice, and report a significant positive improvement of histopathology in our treatment group. Taken together, we demonstrate a novel conditional model of endplate-oriented disc herniation in mouse. We establish ADGRG6 and STAT3 as novel regulators of endplate integrity of the intervertebral disc in mouse and suggest that modulation of ADGRG6/STAT3 signaling could provide robust disease-modifying targets for endplate-oriented disc degeneration in humans.
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Affiliation(s)
- Zhaoyang Liu
- Department of Nutritional Sciences, University of Texas at Austin, Austin, Texas, United States of America
- Department of Pediatrics, Dell Pediatric Research Institute, University of Texas at Austin Dell Medical School, Austin, Texas, United States of America
| | - Garrett W. D. Easson
- Department of Orthopedics, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Jingjing Zhao
- Department of Bioengineering and Therapeutic Sciences and Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
| | - Nadja Makki
- Department of Bioengineering and Therapeutic Sciences and Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, Florida, United States of America
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences and Institute for Human Genetics, University of California San Francisco, San Francisco, California, United States of America
| | - Matthew J. Hilton
- Department of Orthopedic Surgery and Cell Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Simon Y. Tang
- Department of Orthopedics, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Ryan S. Gray
- Department of Nutritional Sciences, University of Texas at Austin, Austin, Texas, United States of America
- Department of Pediatrics, Dell Pediatric Research Institute, University of Texas at Austin Dell Medical School, Austin, Texas, United States of America
- * E-mail:
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7
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Synchrotron tomography of intervertebral disc deformation quantified by digital volume correlation reveals microstructural influence on strain patterns. Acta Biomater 2019; 92:290-304. [PMID: 31082569 DOI: 10.1016/j.actbio.2019.05.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/01/2019] [Accepted: 05/07/2019] [Indexed: 11/22/2022]
Abstract
The intervertebral disc (IVD) has a complex and multiscale extracellular matrix structure which provides unique mechanical properties to withstand physiological loading. Low back pain has been linked to degeneration of the disc but reparative treatments are not currently available. Characterising the disc's 3D microstructure and its response in a physiologically relevant loading environment is required to improve understanding of degeneration and to develop new reparative treatments. In this study, techniques for imaging the native IVD, measuring internal deformation and mapping volumetric strain were applied to an in situ compressed ex vivo rat lumbar spine segment. Synchrotron X-ray micro-tomography (synchrotron CT) was used to resolve IVD structures at microscale resolution. These image data enabled 3D quantification of collagen bundle orientation and measurement of local displacement in the annulus fibrosus between sequential scans using digital volume correlation (DVC). The volumetric strain mapped from synchrotron CT provided a detailed insight into the micromechanics of native IVD tissue. The DVC findings showed that there was no slipping at lamella boundaries, and local strain patterns were of a similar distribution to the previously reported elastic network with some heterogeneous areas and maximum strain direction aligned with bundle orientation, suggesting bundle stretching and sliding. This method has the potential to bridge the gap between measures of macro-mechanical properties and the local 3D micro-mechanical environment experienced by cells. This is the first evaluation of strain at the micro scale level in the intact IVD and provides a quantitative framework for future IVD degeneration mechanics studies and testing of tissue engineered IVD replacements. STATEMENT OF SIGNIFICANCE: Synchrotron in-line phase contrast X-ray tomography provided the first visualisation of native intact intervertebral disc microstructural deformation in 3D. For two annulus fibrosus volumes of interest, collagen bundle orientation was quantified and local displacement mapped as strain. Direct evidence of microstructural influence on strain patterns could be seen such as no slipping at lamellae boundaries and maximum strain direction aligned with collagen bundle orientation. Although disc elastic structures were not directly observed, the strain patterns had a similar distribution to the previously reported elastic network. This study presents technical advances and is a basis for future X-ray microscopy, structural quantification and digital volume correlation strain analysis of soft tissue.
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8
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Microstructural characterization of annulus fibrosus by ultrasonography: a feasibility study with an in vivo and in vitro approach. Biomech Model Mechanobiol 2019; 18:1979-1986. [PMID: 31222527 PMCID: PMC6825023 DOI: 10.1007/s10237-019-01189-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/12/2019] [Indexed: 12/22/2022]
Abstract
The main function of the intervertebral disc is biomechanical function, since it must resist repetitive high loadings, while giving the spine its flexibility and protecting the spinal cord from over-straining. It partially owes its mechanical characteristics to the lamellar architecture of its outer layer, the annulus fibrosus. Today, no non-invasive means exist to characterize annulus lamellar structure in vivo. The aim of this work was to test the feasibility of imaging annulus fibrosus microstructure in vivo with ultrasonography. Twenty-nine healthy adolescents were included. Ultrasonographies of L3-L4 disc were acquired with a frontal approach. Annulus fibrosus was segmented in the images to measure the thickness of the lamellae. To validate lamellar appearance in ultrasonographies, multimodality images of two cow tail discs were compared: ultrasonography, magnetic resonance and optical microscopy. In vivo average lamellar thickness was 229.7 ± 91.5 μm, and it correlated with patient body mass index and age. Lamellar appearance in the three imaging modalities in vitro was consistent. Lamellar measurement uncertainty was 7%, with good agreement between two operators. Feasibility of ultrasonography for the analysis of lumbar annulus fibrosus structure was confirmed. Further work should aim at validating measurement reliability, and to assess the relevance of the method to characterize annulus alterations, for instance in disc degeneration or scoliosis.
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Walk RE, Tang SY. In vivo contrast-enhanced microCT for the monitoring of mouse thoracic, lumbar, and coccygeal intervertebral discs. JOR Spine 2019; 2:e1058. [PMID: 31463468 PMCID: PMC6686789 DOI: 10.1002/jsp2.1058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022] Open
Abstract
Mouse models are often used for studies of intervertebral disc (IVD) homeostasis and degeneration, yet the relatively small size of the IVD poses challenges for noninvasive, longitudinal imaging modalities. The recently developed contrast-enhanced microCT (CEμCT) using Ioversol has been successful in detecting degenerative changes in the murine IVD ex vivo at the micrometer scale. Further leveraging the superior biocompatibility of Ioversol as a contrast agent, we demonstrate the in vivo use of this CEμCT technique to examine IVDs at multiple spinal sites. Ioversol was administered via tail vein injection (TVI) in growing and adult male FVB/NJ mice (n = 5 /group). The animals were anesthetized and underwent in vivo micro-computed tomographic (microCT) at the coccygeal (CC5/CC6), lumbar (L5/6), and thoracic (T12/T13) IVDs. TVI of Ioversol was well-tolerated by all animals. As Ioversol filtered through the kidneys and accumulated in the bladder, the attenuations of the mouse bladder and kidneys increased due to the high molecular weight of Ioversol, confirming that the Ioversol is biological available. Average IVD attenuations increased 3%-15% following TVI (ANOVA; P < .01). The presence of Ioversol in the IVD combined with high-resolution microCT allow for nondestructive visualization of structural features of the IVD. These results demonstrate CEμCT with Ioversol as a viable strategy for the in vivo monitoring of multiple mouse IVDs during degeneration, disease, and injury.
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Affiliation(s)
- Remy E. Walk
- Department of Biomedical EngineeringWashington University in St. LouisSt. LouisMissouri
| | - Simon Y. Tang
- Department of Biomedical EngineeringWashington University in St. LouisSt. LouisMissouri
- Department of Mechanical Engineering and Materials ScienceWashington University in St. LouisSt. LouisMissouri
- Department of Orthopaedic SurgeryWashington University in St. LouisSt. LouisMissouri
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10
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Piazza M, Peck SH, Gullbrand SE, Bendigo JR, Arginteanu T, Zhang Y, Smith HE, Malhotra NR, Smith LJ. Quantitative MRI correlates with histological grade in a percutaneous needle injury mouse model of disc degeneration. J Orthop Res 2018; 36:2771-2779. [PMID: 29687490 PMCID: PMC6200662 DOI: 10.1002/jor.24028] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 04/19/2018] [Indexed: 02/04/2023]
Abstract
Low back pain due to disc degeneration is a major cause of morbidity and health care expenditures worldwide. While stem cell-based therapies hold promise for disc regeneration, there is an urgent need to develop improved in vivo animal models to further develop and validate these potential treatments. The objectives of this study were to characterize a percutaneous needle injury model of intervertebral disc degeneration in the mouse caudal spine, and compare two non-invasive quantitative imaging techniques, microcomputed tomography and magnetic resonance imaging (MRI), as effective measures of disc degeneration in this model. Percutaneous needle injury of mouse caudal discs was undertaken using different needle sizes and injury types (unilateral or bilateral annulus fibrosus (AF) puncture). Mice were euthanized 4 weeks post-injury, and MRI and microcomputed tomography were used to determine T2 relaxation time of the NP and disc height index, respectively. Disc condition was then further assessed using semi-quantitative histological grading. Bilateral AF puncture with either 27 or 29G needles resulted in significantly lower T2 relaxation times compared to uninjured controls, while disc height index was not significantly affected by any injury type. There was a strong, inverse linear relationship between histological grade and NP T2 relaxation time. In this study, we demonstrated that quantitative MRI can detect disc degeneration in the mouse caudal spine 4 weeks following percutaneous needle injury, and may therefore serve as a surrogate for histology in longitudinal studies of both disc degeneration and cell-based therapies for disc regeneration using this model. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2771-2779, 2018.
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Affiliation(s)
- Matthew Piazza
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sun H. Peck
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Translational Musculoskeletal Research Center, Philadelphia VA Medical Center, Philadelphia, PA, USA
| | - Sarah E. Gullbrand
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Translational Musculoskeletal Research Center, Philadelphia VA Medical Center, Philadelphia, PA, USA
| | - Justin R. Bendigo
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Translational Musculoskeletal Research Center, Philadelphia VA Medical Center, Philadelphia, PA, USA
| | - Toren Arginteanu
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yejia Zhang
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Translational Musculoskeletal Research Center, Philadelphia VA Medical Center, Philadelphia, PA, USA,Department of Physical Medicine and Rehabilitation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Harvey E. Smith
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Translational Musculoskeletal Research Center, Philadelphia VA Medical Center, Philadelphia, PA, USA
| | - Neil R. Malhotra
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Correspondence:, Lachlan J. Smith, Ph.D., Department of Neurosurgery, University of Pennsylvania, 110 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA, 19104; Neil R. Malhotra, M.D., Department of Neurosurgery, University of Pennsylvania, 3rd Floor Silverstein Pavilion, 3400 Spruce St, Philadelphia, PA, 19104
| | - Lachlan J. Smith
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Translational Musculoskeletal Research Center, Philadelphia VA Medical Center, Philadelphia, PA, USA,Correspondence:, Lachlan J. Smith, Ph.D., Department of Neurosurgery, University of Pennsylvania, 110 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA, 19104; Neil R. Malhotra, M.D., Department of Neurosurgery, University of Pennsylvania, 3rd Floor Silverstein Pavilion, 3400 Spruce St, Philadelphia, PA, 19104
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11
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Zhang Z, Xu T, Chen J, Shao Z, Wang K, Yan Y, Wu C, Lin J, Wang H, Gao W, Zhang X, Wang X. Parkin-mediated mitophagy as a potential therapeutic target for intervertebral disc degeneration. Cell Death Dis 2018; 9:980. [PMID: 30250268 PMCID: PMC6155159 DOI: 10.1038/s41419-018-1024-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/26/2018] [Accepted: 09/03/2018] [Indexed: 12/11/2022]
Abstract
Intervertebral disc degeneration (IDD) is a complicated pathological condition blamed for low back pain. Mitochondrion is of vital importance for cellular homeostasis, and mitochondrial dysfunction is considered to be one of the major causes of cellular damage. Mitophagy is a cellular process to eliminate impaired mitochondria and showed protective effects in various diseases; however, its role in IDD is still not clear. Here, we explore the role of Parkin-mediated mitophagy in IDD. In this study, we found that Parkin was upregulated in degenerative nucleus pulposus (NP) tissues in vivo as well as in TNF-α stimulated NP cells in vitro. Knockdown of Parkin by siRNA showed that Parkin is crucial for apoptosis and mitochondrion homeostasis in NP cells. Further study showed that upregulation of Parkin by salidroside may eliminate impaired mitochondria and promote the survival of NP cells through activation of mitophagy in vitro. In in vivo study, we found that salidroside could inhibit the apoptosis of NP cells and ameliorate the progression of IDD. These results suggested that Parkin is involved in the pathogenesis of IDD and may be a potential therapeutic target for IDD.
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Affiliation(s)
- Zengjie Zhang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Tianzhen Xu
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,The Third Affiliated Hospital and Ruian People's Hospital of Wenzhou Medical University, Wansong Road 108#, Ruian, Zhejiang Province, China
| | - Jiaoxiang Chen
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Zhenxuan Shao
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Ke Wang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Yingchao Yan
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Congcong Wu
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jialiang Lin
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Haoli Wang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Weiyang Gao
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China.,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China.,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Xiaolei Zhang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China. .,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China. .,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China. .,Chinese Orthopaedic Regenerative Medicine Society, Ruian, China.
| | - Xiangyang Wang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, West Xueyuan Road 109#, Wenzhou, 325027, Zhejiang Province, China. .,Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, Zhejiang Province, China. .,The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
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12
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Newton MD, Hartner SE, Gawronski K, Davenport EJ, Timmons SC, Baker KC, Maerz T. Nondestructive, indirect assessment of the biomechanical properties of the rat intervertebral disc using contrast-enhanced μCT. J Orthop Res 2018; 36:2030-2038. [PMID: 29314237 DOI: 10.1002/jor.23850] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 12/24/2017] [Indexed: 02/04/2023]
Abstract
Mechanical characterization of the intervertebral disc involves labor-intensive and destructive experimental methodology. Contrast-enhanced micro-computed tomography is a nondestructive imaging modality for high-resolution visualization and glycosaminoglycan quantification of cartilaginous tissues. The purpose of this study was to determine whether anionic and cationic contrast-enhanced micro-computed tomography of the intervertebral disc can be used to indirectly assess disc mechanical properties in an ex vivo model of disc degeneration. L3/L4 motion segments were dissected from female Lewis rats. To deplete glycosaminoglycan, samples were treated with 0 U/ml (Control) or 5 U/ml papain. Contrast-enhanced micro-computed tomography was performed following incubation in 40% Hexabrix (anionic) or 30 mg I/ml CA4+ (cationic) for 24 h (n = 10/contrast agent/digestion group). Motion segments underwent cyclic mechanical testing to determine compressive and tensile modulus, stiffness, and hysteresis. Glycosaminoglycan content was determined using the dimethylmethylene blue assay. Correlations between glycosaminoglycan content, contrast-enhanced micro-computed tomography attenuation, and mechanical properties were assessed via the Pearson correlation. The predictive accuracy of attenuation on compressive properties was assessed via repeated random sub-sampling cross validation. Papain digestion produced significant decreases in glycosaminoglycan content and corresponding differences in attenuation and mechanical properties. Attenuation correlated significantly to glycosaminoglycan content and to all compressive mechanical properties using both Hexabrix and CA4+ . Predictive linear regression models demonstrated a predictive accuracy of attenuation on compressive modulus and stiffness of 79.8-86.0%. Contrast-enhanced micro-computed tomography was highly predictive of compressive mechanical properties in an ex vivo simulation of disc degeneration and may represent an effective modality for indirectly assessing disc compressive properties. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2030-2038, 2018.
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Affiliation(s)
- Michael D Newton
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, Michigan
| | | | - Karissa Gawronski
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, Michigan
| | - Erik J Davenport
- Department of Natural Sciences, Lawrence Technological University, Southfield, Michigan
| | - Shannon C Timmons
- Department of Natural Sciences, Lawrence Technological University, Southfield, Michigan
| | - Kevin C Baker
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, Michigan.,Department of Orthopaedic Surgery, Oakland University - William Beaumont School of Medicine, Rochester, Michigan
| | - Tristan Maerz
- Orthopaedic Research Laboratory, Beaumont Health, Royal Oak, Michigan.,Department of Orthopaedic Surgery, Oakland University - William Beaumont School of Medicine, Rochester, Michigan.,Department of Orthopaedic Surgery, University of Michigan, 109 Zina Pitcher Place, 48109, Ann Arbor, Michigan
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