The experimental research of the effects of calcitonin on cytokines and apoptosis of articular chondrocytes during the development of knee osteoarthritis in rabbits

Objective To explore the effects of calcitonin(CT) on cytokines and apoptosis of articular chondrocytes during the development of knee osteoarthritis in rabbits.Methods Thirty-six rabbits were randomly divided into 3 groups: normal group(group A),model group(group B),and CT treatment group(group C).The rabbits in group B and C were made into knee osteoarthritis by modified Hulth's method.The rabbits in group A were dealt with no procedure except the incision of skin and articular cavity.The rabbits in group C were administered with hypodermic injection of CT everyday(5 U/kg).The other rabbits were administered with normal saline injection.All rabbits were sacrifised after continuous treatment for 20 days.The pathology and apoptosis of articular cartilage,variation of cytokines IL-1,TNF-a,and NO in synovial fluid,collagen type II,and MMP-1,and the effect of CT,were observed.Results The JP and Mankin's scores of rabbits in group B were significantly higher than those in group A.The articular cartilage injury of rabbits in group B was also severer than that in group A.Meanwhile,the content of IL-1,TNF-α,and NO in synovial fluid significantly increased(P0.05).The content of collagen type II significantly decreased and MMP-1 activity and the percent of apoptotic articular chondrocytes significantly increased(P0.05).Comparing to group B,the content of IL-1,TNF-α,and NO in synovial fluid of rabbits significantly decreased(P0.05),the articular cartilage injury reduced and the content of collagen type II significantly increased,and MMP-1 activity and the percent of apoptotic articular chondrocytes significantly decreased(P0.05),in group C.Conclusion The efficacy of CT on KOA may be related to the recovery of the imbalance of both cytokines and synthesis-degradation of cartilage matrix.