The role of IGF-I and IGF-binding proteins in osteoarthritis

胰岛素样生长因子（IGF）促进骨和软骨的分化和增殖，并在正常软骨的代谢中起重要作用。由于受损软骨组织的修复受损，我们认为IGF的作用可能是不寻常的OA。IGF与结合蛋白（IGFBPs）一起存在于血清或组织中，软骨细胞产生组织特异性IGFBPs。因此，IGFBPs不仅携带IGF到达靶器官，而且作为IGF的局部调节因子具有重要作用。我们从蛋白和mRNA水平检测了OA软骨产生的IGFBPs，并与正常软骨进行了比较. OA软骨在含10%FBS的DMEM中培养，通过Western配体印迹和免疫印迹法检测IGFBP。从软骨中提取t-RNA，并通过RT-PCR鉴定每个IGFBP的mRNA。结果发现OA软骨中IGFBP-2、3、4和5的产生增加.采用免疫组织化学和原位杂交方法检测各IGFBP在OA软骨组织中的表达。OA软骨中IGFBPs的表达较正常软骨明显增加。

Insulin like growth factor (IGF) promotes a differentiation and proliferation of bone and cartilage, and plays an important role in the metabolism of normal cartilage. Since the repair of the damaged cartilage tissue was impaired, we assume that the IGF action might be unusual in OA. IGF exists in the serum or in the tissue with binding proteins (IGFBPs), and chondrocytes produce tissue specific IGFBPs. Therefore, IGFBPs not only carry IGF to a target organ, but having an important role as a local regulation factor of IGF. We examined the IGFBPs produced by OA cartilage on protein and mRNA levels, and compared them with the normal cartilage.1. OA cartilage was cultivated in DMEM containing 10 % FBS, and IGFBP was detected by the Western ligand blotting followed by the Immune-blotting method. t-RNA was extracted from the cartilage and the mRNA of each IGFBP was identified by RT-PCR. As a result, increased production of IGFBP-2,3,4 and 5 was found in OA cartilage.2. The expression pattern of each IGFBP in the cartilage tissue of OA was examined by the immunohistochemistry and in-situ-hybridization method. In OA cartilage, the expression of each IGFBPs was increased comparing to the normal.