伸膝制动骨关节炎动物模型软骨内胶原变化的观察

Transformation of collagen in osteoarthritic cartilage in rabbits

目的 对骨关节炎 (OA)早期软骨内胶原变化进行动态观察 ,探讨胶原变化与OA发病机制的关系。方法 采用兔膝关节伸直位制动OA模型 ,对制动 10、2 0、3 0、40d的关节软骨进行透射电镜观察 ,Ⅱ型胶原原位杂交 ,Ⅰ、Ⅱ、Ⅲ型胶原的免疫组织化学测定。结果 电镜观察显示OA关节软骨的破坏从切线层的细胶原纤维网开始 ,而切线层的细胶原纤维网不含细胞 ;原位杂交和免疫组织化学显示OA早期Ⅱ型胶原的表达和含量增加 ,而且增加主要发生在移行层和深层上部 ,二者染色灰度值随时间的变化是先递增 ,之后逐渐减少 ;OA关节软骨内有Ⅲ型胶原分泌 ,并呈增加趋势 ,但无Ⅰ型胶原的分泌。结论 OA关节软骨的退变从切线层开始 。

Objective To observe the change of collagen in osteoarthritis and study the pathogenesis of osteoarthritis.Methods The right hind limb of twenty-four adult New Zealand White rabbits were immobilized with plaster cast in extension position for 10,20,30 and 40 days,respectively.Six animals without immobilization served as control.The articular cartilage of the medial femur condyle was harvested for transmission electron microscopy,in-situ hybridization of collagenⅡ,and immunohistochemistry of collagenⅠ,Ⅱ,Ⅲ.Results Transmission electron microscopy showed articular cartilage was destructed from the fine collagen fiber network of tangential zone.The fine collagen fiber network did not contain chondrocyte.Immunohistochemistry and in-situ hybridization showed that in earlier period of osteoarthritis,the collagen typeⅡand its gene expression firstly increased,then decreased with destruction of ultrastructure,and chondrocytes enhanced type Ⅱ collagen expressing and synthesizing mainly in transition zone and upper deep zone.In articular cartilage of osteoarthritis there was type Ⅲ collagen,instead of typeⅠcollagen.Conclusion In osteoarthritis,articular cartilage degenerated from tangential layer,in which collagen can not be repaired after destruction,this may contribute to the chondral degeneration.