基质金属蛋白酶及其组织抑制物在db/db小鼠糖尿病肾病中的表达和活性

目的]探讨基质金属蛋白酶(MMP-s)和基质金属蛋白酶抑制物(TIMPs)在db/db小鼠糖尿病肾病发病机制中的作用。方法]6例db/db小鼠肾组织标本,用蛋白质印迹法检测MMP-2、MMP-9、TIMP-1、TIMP-2蛋白的表达,用白明胶酶谱法检测MMP-2和MMP-9活性。结果]与db/m小鼠相比,db/db小鼠肾脏MMP-2、MMP-9蛋白质的表达分别下降了55.4％和30.1％(P<0.05);而TIMP-1和TIMP-2蛋白质表达分别上升了272.5％和48.8％(P<0.01)。db/db小鼠肾脏MMP-9的活性较db/m小鼠明显下降(85.9％,P<0.001);MMP-2的活性在db/db小鼠和db/m小鼠肾脏中均检测不到。结论]db/db小鼠肾脏中MMP-s-蛋白表达和活性下降,而TIMPs蛋白表达上升,使细胞外基质降解减少,积聚增多,是db/db小鼠糖尿病肾病主要发病机制之一。

Expression and Activity of Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases in the Kidney of db/db Mice

Objective] To study the pathogenic role of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) in diabetic nephropathy by evaluating the expression and activity of MMPs- and TIMPs in the kidney of db/db mice. Methods] Kidney tissues from 6 diabetic db/db mice were investigated. Protein expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 was analyzed by western blot. The activity of MMP-2 and MMP-9 was measured by zymography. Results] Protein expression of MMP-2 and MMP-9 in kidney of db/db mice was significantly lower than that in kidney of db/m mice (55. 4% and 30. 1% lower respectively, P < 0. 05). The expression of both TIMP-1 and TIMP-2 proteins in kidney of db/db mice was significantly higher than that in db/m mice (272. 5% and 48. 8% higher, respectively, P < 0. 01). The activity of MMP-9 in kidney of db/db mice was significantly lower than that in db/m mice (85. 9% lower, P < 0. 001). The activity of MMP-2 was not detectable either in the kidney of db/db mice or db/m mice. Conclusion] Decreased expression and activity of MMPs-and increased expression of TIMPs might contribute to the mesangial expansion characteristic of diabetic nephropathy in the kidney of db/db mice by decreasing extracellular matrix (ECM) degradation.