羧甲基化几丁质降低兔实验性骨关节炎软骨基质金属蛋白酶-1表达的实验研究

Carboxymethylated chitin reduces MMP-1 expression in rabbit ACLT osteoarthritic cartilage

目的 观察羧甲基化几丁质 (CMC)经关节内注射后对兔前交叉韧带切断 (ACLT)骨关节炎模型中软骨退变及软骨基质金属蛋白酶 1(MMP 1)表达及分布的影响。方法 2 0只大白兔行单侧ACLT ,随机选取 10只作实验组 ,于术后第 1、3、5周分别给予 0 3ml 2 %CMC关节内注射 ,另 10只于同一时间点给予 0 3ml生理盐水关节内注射作对照组。术后第 6周处死大白兔 ,对比两组大白兔股骨髁关节软骨的大体改变和光镜下的病理改变 ,并用反转录 聚合酶链反应 (RT PCR)及免疫组织化学的方法检测MMP 1在软骨中的mRNA和蛋白表达。结果 实验组软骨退变的大体评分和光镜下Mankin′s评分都显著低于对照组 ,RT PCR亦显示MMP 1在实验组中的表达明显低于其在对照组中的表达。免疫组织化学显示MMP 1主要表达于软骨表层及中上层 ,实验组MMP 1表达量亦明显低于对照组。结论 CMC能明显降低骨关节炎 (OA)软骨中MMP 1的mRNA和蛋白表达水平 ,并明显降低软骨退变的程度 ,有可能成为防治OA的良好药物。

Objective Using experimental rabbit unilateral anterior cruciate ligament transection (ACLT) model of osteoarthritis (OA) to examine the in vivo effects of carboxymethylated chitin (CMC),intra-articularly given,on cartilage degradation and the level as well as distribution of cartilage matrix metalloproteinase-1 (MMP-1).Methods OA was induced in 20 rabbits by ACLT.Randomly selected 10 rabbits as experiment group and gave them intra-articular injection of 0.3 ml of 2% CMC solution at 1,3,5 weeks after ACLT.Other 10 rabbits received intra-articular injection of 0.3 ml normal saline at the same time respectively as controls.All knees were harvested at 6 weeks post-surgery.Cartilage degradation of femoral condyles was evaluated at the following two levels:macroscopic and light microscopic.Tissue level and distribution of MMP-1 was documented by immunohistochemistry.Results Cartilage degradation in control group was significantly more severe than that in experimental group both in macroscopic grading scale and in Mankin′s grading scale.Immunohistochemical study showed the MMP-1 was predominantly expressed in the superficial and upper intermediate layers of cartilage,RT-PCR and immunohistochemistry both demonstrated the amount of MMP-1 expression in experimental group was greater in control group than that in experimental group.Conclusion CMC could significantly reduce the severity of cartilage degradation and reduce the expression of MMP-1 in cartilage both at protein level and at mRNA level,it would be a potential drug for the treatment of OA.