丝裂酶原活化蛋白激酶激酶1/2抑制对家兔关节软骨保护作用的研究

目的评价丝裂酶原活化蛋白激酶（mitogen—activated protein kinase，MAPK）信号转导通路中MAPK激酶1／2（MEKI／2）在骨关节炎发病过程中的作用。方法新西兰家兔30只，制作OA模型，随机分成3组，每组10只。从造模术后第4天开始，第1组和第2组分别注射100μmol／L和40μmol／L的PD98059，第3组注射PBS液体作为安慰剂对照组，每周2次。另取10只家兔，正常关节内注射PBS液体作为正常对照组。8周后处死动物，进行股骨髁关节软骨退变的大体评分。用Western Blot印记杂交法测定软骨组织中ERK1／2以及磷酸化ERK1／2的表达。用实时定量PCR方法测定基质金属蛋白酶-1／13（MMp-1／13）的mRNA表达水平。结果与使用PBS的安慰剂对照组相比，使用PD98059的关节软骨破坏明显减轻。磷酸化的ERK1／2在100μmol／LPD98059干预组明显低于40μmol／L干预组和安慰剂对照组。而MMP-1／13的mRNA表达在不同浓度的干预组均低于安慰剂对照组。结论MAPK信号转导通路参与了骨关节炎关节软骨破坏的病理过程。MEK1／2选择性阻滞剂PD98059可以在关节炎动物活体内有效抑制关节炎软骨破坏的程度，该作用可能与其有效抑制ERK1／2的磷酸化激活有关。

Inhibition of mitogen-activated protein kinase kinase 1/2 reduce joint cartilage destruction in rabbit model

Objective To observe the protective effect of PD98059,a selective inhibitor of mitogen-activated protein kinase(MAPK)kinase1/2(MEK1/2)for joint cartilage in rabbit model;to determine the inhibitiod effect of PD98059 for ERK1/2,activated phospho-ERK1/2,MMP-1 and MMP-13 in joint cartilage;and to evaluate the contribution of ERK1/2 signaling pathway in the course of OA.Methods 30 rabbits receiving unilateral anterior cruoiate ligament transection and excision of partial medial meniscus were randomly separated into 3 groups.From the 4th day post operation,PD98059 or placebo were injected into the operated articular cavity twice a week.The first and second group received 100μmol/L and 40 μmol/L PD98059 respectively,the third group received PBS as placebo.Another 10 rabbits without any surgery received PBS,acting as a control group.Rabbits were killed at 8 weeks after surgery.Knees were harvested to observe the pathologic changes of joint cartilage.Cartilage near the lesion was obtained;protein of ERKl/2and phospho-ERK1/2 were detected through Western Blot;expression of MMP-1 and MMP-13 were detected through both real-time PCR and Western Blot.Results Knees treated with PD98059 showed decreased in joint cartilage's destruction compared with those treated with PBS.Phospho-ERK1/2 in joint cartilage from rabbits treated with 100 μmol/L PD98059 decreased obviously compared with those treated with 40 μmol/L PD98059 or the placebo.Both mRNA and protein expression of MMP-1 and MMP-13 in all those treated with PD98059 were lower than that in the placebo group.Conclusion MAPK signaling pathways play active roles in the course of OA.PD98059,a selective inhibitor of MAPK kinase1/2(MEK1/2)effectively reduces joint cartilage's destruction in experimental osteoarthritis of rabbits and the protective effect is positively associated with inhibition of ERK1/2 activation.