Protection effects of calcitonin on articular cartilage and subchondral bone of rat knee joint with osteoarthritis / 中国矫形外科杂志

ABSTRACT

[Objective]To investigate the protective effects of calcitonin on articular cartilage and subchondral bone in experimental osteoarthritis induced by ACLT(anterior cruciate ligament transection) of rats. [Methods]Thirty 12-week-old Sprague Dawley rats were divided randomly into three groups Sham(n=10),ACLT+CT(n=10) and ACLT+NS(n=10).ACLT+CT group received a daily subcutaneous injection of salmon calcitonin at a dose of 10 IU.kg-1.d-1 for 12 weeks,ACLT+NS group received NS at the same dose.All rats were sacrificed at 12 weeks after operation.The macro-pathological changes of Samples were graded by Mankin's scale.Bone mineral density(BMD) of right distal femoras and femora condyles were measured by dual-energy X-ray absorptiometry scanner.The decalcified right femora condyles were prepared for paraffin sections,stained with safranin-O/fast green and immunohistochemistry for MMP-13.The right proximal tibias were harvested to make undecalcified bone section for detecting the bone histomorphometry of subchondral bone.[Results](1) The Mankin score of the Sham and ACLT+CT groups were significantly lower than that of ACLT+NS group.(2) The BMD and bone mass(BV/TV,Tb.Th) of the subchondral bone in ACLT+NS were significantly higher than those of Sham and ACLT+CT groups.(3)In ACLT+ NS group,expression level of MMP-13 was significantly lower than those of Sham and ACLT+ CT groups.[Conclusion]A daily subcutaneous injection of salmon calcitonin at a dose of 10 IU.kg-1.d-1 of body weight for 12 weeks can inhibit articular cartilage degeneration of rat osteoarthritic joints,inhibitiing sclerosis of and improving the microarchitecture of subchondral bone,coupled with downregulation of MMP-13 in cartilage probably participate in this process.