Objectives. During open orthopaedic surgery, joints may be exposed to air, potentially leading to cartilage drying and chondrocyte death, however, the long-term effects of joint drying in vivo are poorly understood. We used an animal model to investigate the subsequent effects of joint drying on cartilage and chondrocytes. Methods. The patellar groove of anaesthetised rats was exposed (sham-operated), or exposed and then subjected to laminar airflow (0.25m/s; 60 minutes) before wounds were sutured and animals recovered. Animals were monitored for up to eight weeks and then sacrificed. Cartilage and chondrocyte properties were studied by histology and confocal microscopy, respectively. Results. Joint drying caused extensive chondrocyte death within the superficial regions of cartilage. Histology of dried cartilage demonstrated a loss of surface integrity at four weeks, fibrillations at eight weeks, and an increased modified Mankin score (p < 0.001). Cartilage thickness increased (p < 0.001), whereas chondrocyte density decreased at four weeks (p < 0.001), but then increased towards sham-operated levels (p < 0.01) at eight weeks. By week eight, chondrocyte pairing/clustering and cell volume increased (p < 0.05; p < 0.001, respectively). Conclusions. These in vivo results demonstrated for the first time that as a result of laminar airflow, cartilage degeneration occurred which has characteristics similar to those seen in early osteoarthritis. Maintenance of adequate cartilage hydration during open orthopaedic surgery is therefore of paramount importance. Cite this article: Dr A. Hall. Drying of open animal joints in vivo subsequently causes cartilage degeneration. Bone Joint Res 2016;5:137–144. DOI: 10.1302/2046-3758.54.2000594

Objectives. Osteoarthritis (OA) is characterised by articular cartilage degradation. MicroRNAs (miRNAs) have been identified in the development of OA. The purpose of our study was to explore the functional role and underlying mechanism of miR-138-5p in interleukin-1 beta (IL-1β)-induced extracellular matrix (ECM) degradation of OA cartilage. Materials and Methods. Human articular cartilage was obtained from patients with and without OA, and chondrocytes were isolated and stimulated by IL-1β. The expression levels of miR-138-5p in cartilage and chondrocytes were both determined. After transfection with miR-138-5p mimics, allele-specific oligonucleotide (ASO)-miR-138-5p, or their negative controls, the messenger RNA (mRNA) levels of aggrecan (ACAN), collagen type II and alpha 1 (COL2A1), the protein levels of glycosaminoglycans (GAGs), and both the mRNA and protein levels of matrix metalloproteinase (MMP)-13 were evaluated. Luciferase reporter assay, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot were performed to explore whether Forkhead Box C1 (FOCX1) was a target of miR-138-5p. Further, we co-transfected OA chondrocytes with miR-138-5p mimics and pcDNA3.1 (+)-FOXC1 and then stimulated with IL-1β to determine whether miR-138-5p-mediated IL-1β-induced cartilage matrix degradation resulted from targeting FOXC1. Results. MiR-138-5p was significantly increased in OA cartilage and in chondrocytes in response to IL-1β-stimulation. Overexpression of miR-138-5p significantly increased the IL-1β-induced downregulation of COL2A1, ACAN, and GAGs, and increased the IL-1β-induced over expression of MMP-13.We found that FOXC1 is directly regulated by miR-138-5p. Additionally, co-transfection with miR-138-5p mimics and pcDNA3.1 (+)-FOXC1 resulted in higher levels of COL2A1, ACAN, and GAGs, but lower levels of MMP-13. Conclusion. miR-138-5p promotes IL-1β-induced cartilage degradation in human chondrocytes, possibly by targeting FOXC1. Cite this article: Y. Yuan, G. Q. Zhang, W. Chai,M. Ni, C. Xu, J. Y. Chen. Silencing of microRNA-138-5p promotes IL-1β-induced cartilage degradation in human chondrocytes by targeting FOXC1: miR-138 promotes cartilage degradation. Bone Joint Res 2016;5:523–530. DOI: 10.1302/2046-3758.510.BJR-2016-0074.R2

Objectives. This study aimed to explore the role of miR-320a in the pathogenesis of osteoarthritis (OA). Methods. Human cartilage cells (C28/I2) were transfected with miR-320a or antisense oligonucleotides (ASO)-miR-320a, and treated with IL-1β. Subsequently the expression of collagen type II alpha 1 (Col2α1) and aggrecan (ACAN), and the concentrations of sulfated glycosaminoglycans (sGAG) and matrix metallopeptidase 13 (MMP-13), were assessed. Luciferase reporter assay, qRT-PCR, and Western blot were performed to explore whether pre-B-cell leukemia Homeobox 3 (PBX3) was a target of miR-320a. Furthermore, cells were co-transfected with miR-320a and PBX3 expressing vector, or cells were transfected with miR-320a and treated with a nuclear factor kappa B (NF-κB) antagonist MG132. The changes in Col2α1 and ACAN expression, and in sGAG and MMP-13 concentrations, were measured again. Statistical comparisons were made between two groups by using the two-tailed paired t-test. Results. Expression of miR-320a was elevated in OA cartilage tissues and chondrocytes, and in IL-1β-stimulated C28/I2 cells (p < 0.05 or p < 0.01). MiR-320a overexpression enhanced IL-1β-induced down-regulation of Col2α1 and ACAN and sGAG, and increased the IL-1β-induced overexpression of MMP-13 (p < 0.01). PBX3 was a direct target of miR-320a. PBX3 and MG132 co-transfection attenuated the effects of miR-320a on the expression of Col2α1, ACAN, sGAG and MMP-13(p < 0.01). Conclusion. Overexpression of miR-320a might enhance IL-1β-induced cartilage degradation factors. These effects might be via targeting PBX3 and regulating NF-κB. Cite this article: Y. Jin, X. Chen, Z. Y. Gao, K. Liu, Y. Hou, J. Zheng. The role of miR-320a and IL-1β in human chondrocyte degradation. Bone Joint Res 2017;6:–203. DOI: 10.1302/2046-3758.64.BJR-2016-0224.R1

Objectives. The aim of this study was to investigate the role of miR-126 in the development of osteoarthritis, as well as the potential molecular mechanisms involved, in order to provide a theoretical basis for osteoarthritis treatment and a novel perspective for clinical therapy. Methods. Human chondrocyte cell line CHON-001 was administrated by different doses of interleukin (IL)-1β to simulate inflammation. Cell viability, migration, apoptosis, IL-6, IL-8, and tumour necrosis factor (TNF)-α expression, as well as expression of apoptosis-related factors, were measured to assess inflammation. miR-126 expression was measured by quantitative polymerase chain reaction (qPCR). Cells were then transfected with miR-126 inhibitor to assess the effect of miR-126 on IL-1β-injured CHON-001 cells. Expression of B-cell lymphoma 2 (Bcl-2) and the activity of mitogen-activated protein kinase (MAPK) / Jun N-terminal kinase (JNK) signaling pathway were measured by Western blot to explore the underlying mechanism through which miR-126 affects IL-1β-induced inflammation. Results. After IL-1β administration, cell viability and migration were suppressed while apoptosis was enhanced. Expression of IL-6, IL-8, and TNF-α were all increased, and miR-126 was upregulated. In IL-1β-administrated CHON-001 cells, miR-126 inhibitor suppressed the effect of IL-1β on cell viability, migration, apoptosis, and inflammatory response. Bcl-2 expression was negatively regulated with miR-126 in IL-1β-administrated cells, and thus affected expressions of phosphorylated MAPK and JNK. Conclusion. IL-1β-induced inflammatory markers and miR-126 was upregulated. Inhibition of miR-126 decreased IL-1β-induced inflammation and cell apoptosis, and upregulated Bcl-2 expression via inactivating the MAKP/JNK signalling pathway. Cite this article: C. D. Yu, W. H. Miao, Y. Y. Zhang, M. J. Zou, X. F. Yan. Inhibition of miR-126 protects chondrocytes from IL-1β induced inflammation via upregulation of Bcl-2. Bone Joint Res 2018;7:414–421. DOI: 10.1302/2046-3758.76.BJR-2017-0138.R1

Objectives. The aim of this experimental study on New Zealand’s white rabbits was to investigate the transplantation of autogenous growth plate cells in order to treat the injured growth plate. They were assessed in terms of measurements of radiological tibial varus and histological characteristics. . Methods. An experimental model of plate growth medial partial resection of the tibia in 14 New Zealand white rabbits was created. During this surgical procedure the plate growth cells were collected and cultured. While the second surgery was being performed, the autologous cultured growth plate cells were grafted at the right tibia, whereas the left tibia was used as a control group. . Results. Histological examinations showed that the grafted right tibia presented the regular shape of the plate growth with hypertrophic maturation, chondrocyte columniation and endochondral calcification. Radiological study shows that the mean tibial deformity at the left angle was 20.29° (6.25 to 33) and 7.21° (5 to 10) in the right angle. . Conclusion. This study has demonstrated that grafting of autogenous cultured growth plate cells into a defect of the medial aspect of the proximal tibial physis can prevent bone bridge formation, growth arrest and the development of varus deformity. Cite this article: Bone Joint Res 2014;3:310–16

Objectives. Adult mice lacking the transcription factor NFAT1 exhibit osteoarthritis (OA). The precise molecular mechanism for NFAT1 deficiency-induced osteoarthritic cartilage degradation remains to be clarified. This study aimed to investigate if NFAT1 protects articular cartilage (AC) against OA by directly regulating the transcription of specific catabolic and anabolic genes in articular chondrocytes. Methods. Through a combined approach of gene expression analysis and web-based searching of NFAT1 binding sequences, 25 candidate target genes that displayed aberrant expression in Nfat1. -/-. AC at the initiation stage of OA, and possessed at least four NFAT1 binding sites in the promoter of each gene, were selected and tested for NFAT1 transcriptional activities by chromatin immunoprecipitation (ChIP) and promoter luciferase reporter assays using chondrocytes isolated from the AC of three- to four-month-old wild-type mice or Nfat1. -/-. mice with early OA phenotype. Results. Chromatin immunoprecipitation assays revealed that NFAT1 bound directly to the promoter of 21 of the 25 tested genes encoding cartilage-matrix proteins, growth factors, inflammatory cytokines, matrix-degrading proteinases, and specific transcription factors. Promoter luciferase reporter assays of representative anabolic and catabolic genes demonstrated that NFAT1-DNA binding functionally regulated the luciferase activity of specific target genes in wild-type chondrocytes, but not in Nfat1. -/-. chondrocytes or in wild-type chondrocytes transfected with plasmids containing mutated NFAT1 binding sequences. Conclusion. NFAT1 protects AC against degradation by directly regulating the transcription of target genes in articular chondrocytes. NFAT1 deficiency causes defective transcription of specific anabolic and catabolic genes in articular chondrocytes, leading to increased matrix catabolism and osteoarthritic cartilage degradation. Cite this article: M. Zhang, Q. Lu, T. Budden, J. Wang. NFAT1 protects articular cartilage against osteoarthritic degradation by directly regulating transcription of specific anabolic and catabolic genes. Bone Joint Res 2019;8:90–100. DOI: 10.1302/2046-3758.82.BJR-2018-0114.R1

Objectives. The role of mechanical stress and transforming growth factor beta 1 (TGF-β1) is important in the initiation and progression of osteoarthritis (OA). However, the underlying molecular mechanisms are not clearly known. Methods. In this study, TGF-β1 from osteoclasts and knee joints were analyzed using a co-cultured cell model and an OA rat model, respectively. Five patients with a femoral neck fracture (four female and one male, mean 73.4 years (68 to 79)) were recruited between January 2015 and December 2015. Results showed that TGF-β1 was significantly upregulated in osteoclasts by cyclic loading in a time- and dose-dependent mode. The osteoclasts were subjected to cyclic loading before being co-cultured with chondrocytes for 24 hours. Results. A significant decrease in the survival rate of co-cultured chondrocytes was found. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) assay demonstrated that mechanical stress-induced apoptosis occurred significantly in co-cultured chondrocytes but administration of the TGF-β1 receptor inhibitor, SB-505124, can significantly reverse these effects. Abdominal administration of SB-505124 can attenuate markedly articular cartilage degradation in OA rats. Conclusion. Mechanical stress-induced overexpression of TGF-β1 from osteoclasts is responsible for chondrocyte apoptosis and cartilage degeneration in OA. Administration of a TGF-β1 inhibitor can inhibit articular cartilage degradation. Cite this article: R-K. Zhang, G-W. Li, C. Zeng, C-X. Lin, L-S. Huang, G-X. Huang, C. Zhao, S-Y. Feng, H. Fang. Mechanical stress contributes to osteoarthritis development through the activation of transforming growth factor beta 1 (TGF-β1). Bone Joint Res 2018;7:587–594. DOI: 10.1302/2046-3758.711.BJR-2018-0057.R1

Objectives. This study aimed to examine the effects of SRT1720, a potent SIRT1 activator, on osteoarthritis (OA) progression using an experimental OA model. Methods. Osteoarthritis was surgically induced by destabilization of the medial meniscus in eight-week-old C57BL/6 male mice. SRT1720 was administered intraperitoneally twice a week after surgery. Osteoarthritis progression was evaluated histologically using the Osteoarthritis Research Society International (OARSI) score at four, eight, 12 and 16 weeks. The expression of SIRT1, matrix metalloproteinase 13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5), cleaved caspase-3, PARP p85, and acetylated nuclear factor (NF)-κB p65 in cartilage was examined by immunohistochemistry. Synovitis was also evaluated histologically. Primary mouse epiphyseal chondrocytes were treated with SRT1720 in the presence or absence of interleukin 1 beta (IL-1β), and gene expression changes were examined by real-time polymerase chain reaction (PCR). Results. The OARSI score was significantly lower in mice treated with SRT1720 than in control mice at eight and 12 weeks associated with the decreased size of osteophytes at four and eight weeks. The delayed OA progression in the mice treated with SRT1720 was also associated with increased SIRT1-positive chondrocytes and decreased MMP-13-, ADAMTS-5-, cleaved caspase-3-, PARP p85-, and acetylated NF-κB p65-positive chondrocytes and decreased synovitis at four and eight weeks. SRT1720 treatment partially rescued the decreases in collagen type II alpha 1 (COL2A1) and aggrecan caused by IL-1β, while also reducing the induction of MMP-13 by IL-1β in vitro. Conclusion. The intraperitoneal injection of SRT1720 attenuated experimental OA progression in mice, indicating that SRT1720 could be a new therapeutic approach for OA. Cite this article: K. Nishida, T. Matsushita, K. Takayama, T. Tanaka, N. Miyaji, K. Ibaraki, D. Araki, N. Kanzaki, T. Matsumoto, R. Kuroda. Intraperitoneal injection of the SIRT1 activator SRT1720 attenuates the progression of experimental osteoarthritis in mice. Bone Joint Res 2018;7:252–262. DOI: 10.1302/2046-3758.73.BJR-2017-0227.R1

Objectives. Intra-articular injections of local anaesthetics (LA), glucocorticoids (GC), or hyaluronic acid (HA) are used to treat osteoarthritis (OA). Contrast agents (CA) are needed to prove successful intra-articular injection or aspiration, or to visualize articular structures dynamically during fluoroscopy. Tranexamic acid (TA) is used to control haemostasis and prevent excessive intra-articular bleeding. Despite their common usage, little is known about the cytotoxicity of common drugs injected into joints. Thus, the aim of our study was to investigate the effects of LA, GC, HA, CA, and TA on the viability of primary human chondrocytes and tenocytes in vitro. Methods. Human chondrocytes and tenocytes were cultured in a medium with three different drug dilutions (1:2; 1:10; 1:100). The following drugs were used to investigate cytotoxicity: lidocaine hydrochloride 1%; bupivacaine 0.5%; triamcinolone acetonide; dexamethasone 21-palmitate; TA; iodine contrast media; HA; and distilled water. Normal saline served as a control. After an incubation period of 24 hours, cell numbers and morphology were assessed. Results. Using LA or GC, especially triamcinolone acetonide, a dilution of 1:100 resulted in only a moderate reduction of viability, while a dilution of 1:10 showed significantly fewer cell counts. TA and CA reduced viability significantly at a dilution of 1:2. Higher dilutions did not affect viability. Notably, HA showed no effects of cytotoxicity in all drug dilutions. Conclusion. The toxicity of common intra-articular injectable drugs, assessed by cell viability, is mainly dependent on the dilution of the drug being tested. LA are particularly toxic, whereas HA did not affect cell viability. Cite this article: P. Busse, C. Vater, M. Stiehler, J. Nowotny, P. Kasten, H. Bretschneider, S. B. Goodman, M. Gelinsky, S. Zwingenberger. Cytotoxicity of drugs injected into joints in orthopaedics. Bone Joint Res 2019;8:41–48. DOI: 10.1302/2046-3758.82.BJR-2018-0099.R1

Background. Resveratrol is a polyphenolic compound commonly found in the skins of red grapes. Sirtuin 1 (SIRT1) is a human gene that is activated by resveratrol and has been shown to promote longevity and boost mitochondrial metabolism. We examined the effect of resveratrol on normal and osteoarthritic (OA) human chondrocytes. Methods. Normal and OA chondrocytes were incubated with various concentrations of resveratrol (1 µM, 10 µM, 25 µM and 50 µM) and cultured for 24, 48 or 72 hours or for six weeks. Cell proliferation, gene expression, and senescence were evaluated. Results. SIRT1 was significantly upregulated in normal chondrocytes with resveratrol concentrations of 25 µM and 50 µM on both two- (2D) (both p = 0.001) and three-dimensional (3D) cultures (p = 0.008 and 0.001, respectively). It was significantly upregulated in OA chondrocytes treated with 10 µM, 25 µM and 50 µM resveratrol on 2D cultures (p = 0.036, 0.002 and 0.001, respectively) and at 50 µM concentration on 3D cultures (p = 0.001). At 72 hours, the expression of collagen (COL)-10, aggrecan (AGG), and runt-related transcription factor 2 (RUNX2) was significantly greater in both 25 µM (p = 0.011, 0.006 and 0.015, respectively) and 50 µM (p = 0.019, 0.004 and 0.002, respectively) resveratrol-treated normal chondrocyte cultures. In OA chondrocytes, expression of COL10 and RUNX2 was significantly greater in 25 µM (p = 0.004 and 0.024) and 50 µM (p = 0.004 and 0.019) cultures at 72 hours on 3D cultures. Conclusions. At concentrations of 25 µM and/or 50 µM, resveratrol treatment significantly upregulates SIRT1 gene expression in normal and osteoarthritic chondrocytes. Resveratrol induces chondrocytes into a hypertrophic state through upregulation of COL1, COL10, and RUNX2. Cite this article: Bone Joint Res 2014;3:51–9

Objectives. Recent studies have shown that systemic injection of rapamycin can prevent the development of osteoarthritis (OA)-like changes in human chondrocytes and reduce the severity of experimental OA. However, the systemic injection of rapamycin leads to many side effects. The purpose of this study was to determine the effects of intra-articular injection of Torin 1, which as a specific inhibitor of mTOR which can cause induction of autophagy, is similar to rapamycin, on articular cartilage degeneration in a rabbit osteoarthritis model and to investigate the mechanism of Torin 1’s effects on experimental OA. Methods. Collagenase (type II) was injected twice into both knees of three-month-old rabbits to induce OA, combined with two intra–articular injections of Torin 1 (400 nM). Degeneration of articular cartilage was evaluated by histology using the Mankin scoring system at eight weeks after injection. Chondrocyte degeneration and autophagosomes were observed by transmission electron microscopy. Matrix metallopeptidase-13 (MMP-13) and vascular endothelial growth factor (VEGF) expression were analysed by quantitative RT-PCR (qPCR).Beclin-1 and light chain 3 (LC3) expression were examined by Western blotting. Results. Intra-articular injection of Torin 1 significantly reduced degeneration of the articular cartilage after induction of OA. Autophagosomes andBeclin-1 and LC3 expression were increased in the chondrocytes from Torin 1-treated rabbits. Torin 1 treatment also reduced MMP-13 and VEGF expression at eight weeks after collagenase injection. Conclusion. Our results demonstrate that intra-articular injection of Torin 1 reduces degeneration of articular cartilage in collagenase-induced OA, at least partially by autophagy activation, suggesting a novel therapeutic approach for preventing cartilage degeneration and treating OA. Cite this article: N-T. Cheng, A. Guo, Y-P. Cui. Intra-articular injection of Torin 1 reduces degeneration of articular cartilage in a rabbit osteoarthritis model. Bone Joint Res 2016;5:218–224. DOI: 10.1302/2046-3758.56.BJR-2015-0001

Objectives. Mesenchymal stem cells have the ability to differentiate into various cell types, and thus have emerged as promising alternatives to chondrocytes in cell-based cartilage repair methods. The aim of this experimental study was to investigate the effect of bone marrow derived mesenchymal stem cells combined with platelet rich fibrin on osteochondral defect repair and articular cartilage regeneration in a canine model. Methods. Osteochondral defects were created on the medial femoral condyles of 12 adult male mixed breed dogs. They were either treated with stem cells seeded on platelet rich fibrin or left empty. Macroscopic and histological evaluation of the repair tissue was conducted after four, 16 and 24 weeks using the International Cartilage Repair Society macroscopic and the O’Driscoll histological grading systems. Results were reported as mean and standard deviation (. sd. ) and compared at different time points between the two groups using the Mann-Whitney U test, with a value < 0.05 considered statistically significant. Results. Higher cumulative macroscopic and histological scores were observed in stem cell treated defects throughout the study period with significant differences noted at four and 24 weeks (9.25, . sd. 0.5 vs 7.25, . sd. 0.95, and 10, . sd. 0.81 vs 7.5, . sd. 0.57; p < 0.05) and 16 weeks (16.5, . sd. 4.04 vs 11, . sd. 1.15; p < 0.05), respectively. Superior gross and histological characteristics were also observed in stem cell treated defects. Conclusion. The use of autologous culture expanded bone marrow derived mesenchymal stem cells on platelet rich fibrin is a novel method for articular cartilage regeneration. It is postulated that platelet rich fibrin creates a suitable environment for proliferation and differentiation of stem cells by releasing endogenous growth factors resulting in creation of a hyaline-like reparative tissue. Cite this article: D. Kazemi, K. Shams Asenjan, N. Dehdilani, H. Parsa. Canine articular cartilage regeneration using mesenchymal stem cells seeded on platelet rich fibrin: Macroscopic and histological assessments. Bone Joint Res 2017;6:98–107. DOI: 10.1302/2046-3758.62.BJR-2016-0188.R1

The treatment of osteochondral lesions and osteoarthritis remains an ongoing clinical challenge in orthopaedics. This review examines the current research in the fields of cartilage regeneration, osteochondral defect treatment, and biological joint resurfacing, and reports on the results of clinical and pre-clinical studies. We also report on novel treatment strategies and discuss their potential promise or pitfalls. Current focus involves the use of a scaffold providing mechanical support with the addition of chondrocytes or mesenchymal stem cells (MSCs), or the use of cell homing to differentiate the organism’s own endogenous cell sources into cartilage. This method is usually performed with scaffolds that have been coated with a chemotactic agent or with structures that support the sustained release of growth factors or other chondroinductive agents. We also discuss unique methods and designs for cell homing and scaffold production, and improvements in biological joint resurfacing. There have been a number of exciting new studies and techniques developed that aim to repair or restore osteochondral lesions and to treat larger defects or the entire articular surface. The concept of a biological total joint replacement appears to have much potential. Cite this article: Bone Joint Res 2013;2:193–9

Objectives. An experimental piglet model induces avascular necrosis (AVN) and deformation of the femoral head but its secondary effects on the developing acetabulum have not been studied. The aim of this study was to assess the development of secondary acetabular deformation following femoral head ischemia. Methods. Intracapsular circumferential ligation at the base of the femoral neck and sectioning of the ligamentum teres were performed in three week old piglets. MRI was then used for qualitative and quantitative studies of the acetabula in operated and non-operated hips in eight piglets from 48 hours to eight weeks post-surgery. Specimen photographs and histological sections of the acetabula were done at the end of the study. . Results. The operated-side acetabula were wider, shallower and misshapen, with flattened labral edges. At eight weeks, increased acetabular cartilage thickness characterised the operated sides compared with non-operated sides (p < 0.001, ANOVA). The mean acetabular width on the operated side was increased (p = 0.015) while acetabular depth was decreased anteriorly (p = 0.007) and posteriorly (p = 0.44). The cartilage was thicker, with delayed acetabular bone formation, and showed increased vascularisation with fibrosis laterally and focal degenerative changes involving chondrocyte hypocellularity, chondrocyte cloning, peripheral pannus formation and surface fibrillation. . Conclusions. We demonstrate that femoral head AVN in the young growing piglet also induced, and was coupled with, secondary malformation in acetabular shape affecting both articular and adjacent pelvic cartilage structure, and acetabular bone. The femoral head model inducing AVN can also be applied to studies of acetabular maldevelopment, which is less well understood in terms of developing hip malformation. Cite this article: Bone Joint Res 2014;3:130–8

Aim

Osteoarthritis (OA) is caused by complex interactions between genetic and environmental factors. Epigenetic mechanisms control the expression of genes and are likely to regulate the OA transcriptome. We performed integrative genomic analyses to define methylation-gene expression relationships in osteoarthritic cartilage.

Objectives

The objectives of this study were: 1) to examine osteophyte formation, subchondral bone advance, and bone marrow lesions (BMLs) in osteoarthritis (OA)-prone Hartley guinea pigs; and 2) to assess the disease-modifying activity of an orally administered phosphocitrate ‘analogue’, Carolinas Molecule-01 (CM-01).

Objectives

In this study, we compared the pain behaviour and osteoarthritis (OA) progression between anterior cruciate ligament transection (ACLT) and osteochondral injury in surgically-induced OA rat models.

Objectives

After an injury, the biological reattachment of tendon to bone is a challenge because healing takes place between a soft (tendon) and a hard (bone) tissue. Even after healing, the transition zone in the enthesis is not completely regenerated, making it susceptible to re-injury. In this study, we aimed to regenerate Achilles tendon entheses (ATEs) in wounded rats using a combination of kartogenin (KGN) and platelet-rich plasma (PRP).

Objectives

This study aimed to investigate the functional effects of microRNA (miR)-214-5p on osteoblastic cells, which might provide a potential role of miR-214-5p in bone fracture healing.

Objectives

Given the function of adiponectin (ADIPOQ) on the inflammatory condition of obesity and osteoarthritis (OA), we hypothesized that the ADIPOQ gene might be a candidate gene for a marker of susceptibility to OA.