骨关节炎家兔关节软骨中丝裂原活化蛋白激酶信号通路蛋白表达以及活化状况

Expression and activation of mitogen-activated protein kinases in osteoarthritic rabbits' joint cartilage

目的观察骨关节炎家兔关节软骨组织中丝裂原活化蛋白激酶(mitogen-activated protein kinases,MAPKs)信号通路蛋白表达以及活化的时相变化,明确上述蛋白在骨关节炎(osteoarthritis,OA)发展中的作用。方法用30只家兔制作OA模型,分别于术后4、8、12周各处死10只,另选10只行假手术作为对照组。取关节软骨,实时定量RT-PCR测定MAPKs mRNA表达;Western blot法测定MAPKs总蛋白以及磷酸化状态蛋白的表达。结果造模术后几个时间点MAPKs(包括ERK1/2、P38 MAPK、JNK)的基因表达与蛋白表达均无明显变化;与正常对照相比,磷酸化ERK1/2在术后4、8、12周均有高水平表达,磷酸化P38 MAPK术后4周高水平表达,磷酸化JNK术后4、8周高水平表达,其他时间点差异无统计学意义。结论关节炎软骨组织中MAPKs信号通路的活化主要依赖于信号通路蛋白的磷酸化,而非总蛋白表达的上调;信号通路蛋白的活化存在时相差异。

Objective To examine the expression of mitogen-activated protein kinases（MAPKs） in osteoarthritic rabbits’ joint cartilage at different time points after ACLT and partial excision of medial meniscus. Methods Thirty rabbits in experimental groups received unilateral ACLT and partial excision of medial meniscus,another 10 rabbits received unilateral arthrotomy as pseudo-operation control.Then experimental rabbits were sacrificed respectively at 4,8 and 12 weeks after surgery,and 10 pseudo-operation rabbits were sacrificed at 12 weeks after surgery.Knees were harvested to observe the macro pathologic changes of joint cartilage.Cartilage near the lesion was obtained,and mRNA and protein expression of MAPK（including ERK1/2,P38 MAPK and JNK） were detected by real time RT-PCR and Western blot respectively.Results There were no significant changes in mRNA and total protein expression of MAPK at different time points.Compared with control group,phospho-ERK1/2 expression was in high level at 4 weeks,8 weeks and 12 weeks postoperation,phospho-P38 MAPK expression was in high level at 4 weeks postoperation,and phospho-JNK expression was in high level at 4 weeks and 8 weeks postoperation,respectively.Conclusions Activation of MAPKs in osteoarthritic cartilage depends on proteins phosphorylation,rather than total proteins expression.There are phase differences between different MAPKs.