A-2巨球蛋白对骨关节炎软骨细胞的作用

Role of A-2-macroglobulin on osteoarthritic chondrocytes

[目的]研究A-2巨球蛋白(alpha-2-macroglobulin, A2M)在骨关节炎(osteoarthritis, OA)软骨中的表达情况,并观察其对OA软骨细胞的作用。[方法]选取因OA行全膝关节置换术患者胫骨平台24例,将平台软骨面分为相对病变区域与绝对病变区域,q PCR法检测不同区域A2M的表达水平。原代OA软骨细胞进行培养,分为3组:正常培养组(对照组)、IL-1b刺激组、IL-1b刺激后A2M处理组(A2M组),24 h后q PCR法检测软骨细胞合成和分解代谢情况;48 h后,蛋白印迹法检测细胞中基质金属蛋白酶-13 (MMP-13)的表达水平,ELISA法检测上清液中MMP-13的浓度。[结果] OA胫骨平台绝对病变区域A2M表达水平较相对病变区域显著下降(P<0.05)。细胞培养中,A2M组II型胶原和Aggrecan的表达水平显著高于IL-1b刺激组(P<0.05),而MMP-3和-13的表达水平则明显低于IL-1b刺激组(P<0.05)。蛋白印迹和ELISA检测均显示经A2M处理后,MMP-13的水平显著降低。[结论]A2M能够有效地抑制软骨的分解代谢,未来将进行体内试验来验证其对OA的抑制作用。

[Objective] To investigate the expression level of alpha-2-macroglobulin in osteoarthritis(OA) cartilage and its role on OA chondrocytes.[Methods] Samples of tibia plateau were collected from 24 patients undergone total knee arthroplasty(TKA). The cartilage surface was divided into 2 areas: relative normal area and absolute osteoarthritic area. The primary OA chondrocytes were cultured and divided into three groups: the normal culture group(control group), IL-1 b stimulated group(IL-1 b group), and IL-1 b stimulated plus A2M treated group(A2M group). Twenty-four hours later, the m RNA levels of chondrocytes were detected by q PCR, 48 hours later, the expression of matrix metalloproteinase-13(MMP-13) was tested by Western blot and the concentration of MMP-13 in supernatant was detected by ELISA.[Results] The A2M m RNA level in the absolute osteoarthritic area of tibia plateau was significantly lower than that in relative normal area(P<0.05). In chondrocytes culture experiment, the level of anabolism in A2M group was significantly higher than that in IL-1 b group(P<0.05), while the level of catabolism was significantly lower than that in IL-1 b group(P<0.05). Western blot and ELISA showed that the level of MMP-13 decreased significantly after A2M treatment.[Conclusion] A2M does effectively inhibit catabolic metabolism of the chondrocyte. It may be a new strategy for OA treatment in the future, and further study is needed in vivo to test this hypothesis.