Effects of Calcitonin on Articular Cartilage Injury in Rabbits with Knee Osteoarthritis

Objective:To study effects of calcitonin (CT) on the articular cartilage injury in rabbits with knee osteoar thritis.Methods:Thirty-six rabbits were randomly divided into three groups,normal group (group A),model group (group B) and CT treatment group (group C).The modified Hulth ' s method was used to establish the model of knee osteoarthritis in group B and group C.Except for incision of skin and articular cavity,there was no other treatment in group A.The rabbits in group C were treated by hypodermic injection CT (5 U/kg) everyday.The other rabbits were treated by the same dose of nor mal saline.Animals were sacrificed after 20 d injection.The pathomorphism and tumor necrosis factor (TNF)-α,nitric oxide (NO),collagen Ⅱ and MMP-1 were observed.The effect of calcitonin on the above indicator was also detected.Results:Compared with group A,scores of JP and Mankin were significantly higher,articular cartilage injury was more serious,con tents of TNF-α and NO in synovial fluid increased (P 0.05) and the expression of MMP-1 increased,but the expression of collagen Ⅱ decreased (P 0.05) in group B.Compared with group B,contents of TNF-α and NO in synovial fluid decreased significantly (P 0.05),the articular cartilage injury relieved evidently,the expression of collagen Ⅱ increased significantly and the expression of MMP-1 decreased significantly in group C (P 0.05).Conclusion:The protective effect of CT on artic ular cartilage injury was by inhibition of TNF-α and NO.