| Purpose: to evaluate the feasibility of osteoarthritis model by medial meniscal excision and medial collateral ligament amputation of knee in rats,and to investigate the expression of MMP-13 and ADAMTS-5 in cartilage of rat osteoarthritis model at different stages.Methods: Forty female SD rats were randomly divided into model group(n = 30)and sham-operated group(n = 10).The rats in model group accepted medial meniscal excision and medial collateral ligament amputation,and incision of knee capsule and then suture were performed in the rats of sham-operated group.The rats in model group were respectively killed at 4,6 and 8 weeks post-operation,and the rats in sham-operated group were killed at 8 weeks post-operation.The degenerative articular cartilage was observed and the cartilage injury score was evaluated after dissecting the operation knee of rats.And then histological observation was performed via HE Staining.Finally,the residual cartilage tissue was used to compare the expression of MMP-13 and ADAMTS-5 between two groups at different stages by Western blot and immunohistochemistry.Results:(1)Gross observations showed that: cartilage degeneration was visible in model group 4 weeks after operation,and was further aggravated at 6 and 8 weeks after operation.However,no obvious cartilage degeneration in sham-operation group.The difference of articular cartilage injury score in different groups was statistically significant(P<0.05).(2)HE staining results showed that: the cartilage surface of the right knee joint was smooth and the number of chondrocytes was normal in the model group.In the model group,erosion or superficial ulcer could be seen on the cartilage surface of the right knee joint and a little loss of chondrocytes was found in the surface layer of the joint 4 weeks after operation,and the cartilage surface of the right knee joint of rats showed deep fissure,ulcer,erosion,and a small amount of cartilage exfoliation 6 weeks after operation,and most of the cartilage surface of the right knee joint was stripped and most of the chondrocytes were lost in the articular surface of the rats 8 weeks after operation.(3)Western blot results show that: the expression of MMP-13 and ADAMTS-5 were lower in sham-operation group.The expression of MMP-13 began to increase at the 4th week after operation,and continued to increase at the sixth week after operation,but it decreased at the 8th week after operation.There were significant differences in protein expression among rats in sham-operation group,rats 4 weeks post-operation,rats 6 weeks post-operation and rats 8 weeks post-operation(P<0.05).The expression of ADAMTS-5 began to increase at 6 weeks post-operation and maintained until 8 weeks post-operation.There was no significant difference in protein expression between sham-operation group and rats 4 weeks post-operation(P>0.05),and the protein expression in sham operation group was significantly different with rats 6 weeks post-operation in model group and rats 8 weeks post-operation in model group(P<0.05).There was a significant difference in protein expression between the rats 4 weeks post-operation and the rats 6 weeks post-operation,and Difference was also found between the rats 4 weeks post-operation and the rats 8 weeks post-operation(P<0.05).There was no significant difference in the expression of protein in articular cartilage between the rats 6 weeks post-operation and the rats 8 weeks post-operation(P>0.05).The expression trend of protein detected by immunohistochemistry was consistent with that of Western blot.Conclusions: The animal OA model can be established by medial meniscal excision and medial collateral ligament amputation of the knee joint.The expression of MMP-13 and ADAMTS-5 in different stages of OA were significantly changed,so that MMP-13 and ADAMTS-5 can be used as evaluation indexes in the study of OA prevention and treatment,and further research is needed to explore its related signaling pathways. |
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