Objective—To determine if supplemental intra-articular alpha-2 macroglobulin (A2M) has a chondroprotective effect in a rat OA model. Methods—A2M was identified as a potential therapeutic agent by comparing A2M concentrations in serum, synovial fluid (SF), and cartilage from normal and osteoarthritic (OA) patients by Western blotting, mass spectrometry, ELISA, and immunohistochemistry (IHC). The effects of A2M on IL-1-induced cartilage catabolic enzymes were evaluated by Luminex and ELISA in cultured chondrocytes. In vivo effects on cartilage degeneration and MMP-13 concentration were evaluated in male rats (N=120) randomized to four treatments: (1) CLT +saline, (2) ACLT+A2M (1IU/kg), (3) ACLT+A2M (2IU/kg) or (4) sham surgery+saline. Intraarticular injections were given for 6 weeks. The concentration of MMP-13 in SF lavages was Correspondence to: Lei Wei, 401-793-8384(O), (401)444-5872(Fax) Lei_Wei@brown.edu. †These authors contributed in equal measure as the first author. Authors’ contributions: Shaowei Wang participated in the study design, wrote the manuscript, performed most of the experiments and analyzed data. Jingming Zhou, Jing Zhang, and Kai Li performed some of the experiments and analyzed data. Mary Goldring provided the C28 cell line and provided advice on its use. Richard Terek, Braden C. Fleming, Xiaochun Wei and Michael G. Ehrlich provided the human samples. Xiaochun Wei, Jingming Zhou, Jing Zhang, Kai Li, Qian Chen, Richard Terek, Braden C. Fleming, Mary Goldring, Michael G. Ehrlich, and Ge Zhang participated in the interpretation of the data and/or revised the manuscript critically. Lei Wei conceived of the study, participated in its design and data analysis, and revised the manuscript carefully and critically. All authors have read and approved the final manuscript. Disclosures: We have nothing to disclose. NIH Public Access Author Manuscript Arthritis Rheumatol. Author manuscript; available in PMC 2015 July 01. Published in final edited form as: Arthritis Rheumatol. 2014 July ; 66(7): 1843–1853. doi:10.1002/art.38576. N IH -P A A uhor M anscript N IH -P A A uhor M anscript N IH -P A A uhor M anscript measured using ELISA. OA-related gene expression was quantified by RT-qPCR. Histology was performed to grade OA. Results—In both normal and OA patients, the levels of A2M were lower in SF compared to serum, and MMP-13 was higher in SF than serum of OA patients. In vitro, A2M inhibited the induction of MMP-13 by IL-1 in a dose-dependent manner in human chondrocytes. In the rat ACLT OA model, supplemental intra-articular injection of A2M reduced the concentration of MMP-13 in SF, had a favorable effect on OA-related gene expression, and attenuated OA progression. Conclusion—A2M is a plasma protease inhibitor that is not present in sufficient concentrations to inactivate the high concentrations of catabolic factors found in OA SF. Our findings suggest that supplemental intra-articular A2M provides chondral protection for post traumatic OA.

BACKGROUND:Many studies have shown that matrix metal oproteinases 1, 3, 9 and 13 play an important role in articular cartilage degeneration and destruction, but there is less special research on the articular synovium. OBJECTIVE:To observe the effect of long-distance running on the expressions of matrix metal oproteinases 1, 3, 9 and 13 in the synovium. METHODS:Fifteen male Wistar rats were divided into three groups:control group, tablet group and uphil group. Rats in the control group received ordinary captivity;rats in the tablet group ran on the horizontal treadmil (0°) at the speed of 1 km/h for 1 hour daily, and lasted for 45 days;rats in the uphil group daily ran on the horizontal treadmil (0°) at the speed of 1 km/h for 1 hour, and lasted for 15 days, and then the rats ran on the uphil treadmil (+20°) at the speed of 1 km/h for 1 hour daily and lasted for 30 days. The knee joint synovium injury models with varying degrees were established. The dual hind knee joints were obtained after modeling for paraffin-embedded. Then the overal sagittal slices were obtained for hematoxylin-eosin staining and immunohistochemical staining, and the experimental results were observed and analyzed. RESULTS AND CONCLUSION:After long-distance running, the expression of matrix metal oproteinases 1 in synovium of the tablet group and uphil group was increased when compared with that of the control group (P<0.05), but there was no significant difference between tablet group and uphil group (P>0.05). There was no significant difference in matrix metal oproteinases 3 expression (P>0.05). The expressions of matrix metal oproteinase 9 and matrix metal oproteinase 13 in synovium were in gradient increasing state (P<0.05), which were lowest in the control group, increased in the tablet group and highest in the uphil group. The results indicate that long-distance running exercise can influence the normal physiological structure of rat knee joint synovium by changing the expression of matrix metal oproteinases.