中文摘要：

目的观察醛固酮（ALD）刺激对足细胞培养上清液中基质金属蛋白酶2、9（MMP-2、MMP-9）活性、Ⅳ型胶原的影响及探讨ALD对足细胞细胞外基质分泌、降解的调节机制。方法分别用不同浓度ALD（10^-11、10^-9、10^-7mol／L）以不同时间（24、48、72h）作用足细胞，并设立空白对照组。用明胶酶谱、Western印迹、ELISA方法检测培养上清液中MMP-2、MMP-9、Ⅳ型胶原仅5链及TGF-β1；流式细胞仪检测足细胞黏附率，同时观察ALD受体拈抗剂螺内酯（SPI）及TGF-β1受体抑制剂对上述效应的阻断作用。结果与对照组相比，ALD以时问及剂量依赖性导致培养上清液中MMP-2、MMP-9活性升高（P〈0．05）；Ⅳ型胶原仪5链蛋白表达下降（P〈0．05）；TGF-β1蛋白表达升高（P〈0．05）。SPI可完全阻断，而TGF-β1受体抑制剂SB314542可部分阻断ALD刺激足细胞引起的MMP-2、MMP-9活性升高、Ⅳ型胶原α5链蛋白及足细胞黏附率的下降（P〈0．05）。结论ALD通过TGF-β1途径使足细胞MMP-2、MMP-9活性升高，Ⅳ型胶原d5链蛋白表达下降，足细胞黏附率下降，从而使足细胞分泌基底膜成分异常，基底膜合成及降解失衡，导致足细胞损伤。

英文摘要：

objective To assess the effect of aldosterone on the production of matrix metalloproteinase-2 （MMP-2）, matrix metalloproteinase-9 （MMP-9）and collagen Ⅳ in culture supernatants of podocytes and the possible molecular mechanisms involved in the influence of aldosterone on the synthesis and degradation of extracellular matrix produced by podocytes. Methods Podocytes were treated with aldosterone at the concentration of 10^-11, 10^-9, 10^-7 mol/L respectively. Cultured podocytes were examined at 24, 48 and 72 hours respectively. Spironolactone, a receptor antagonist of aldosterone, was added to observe the blocking effect on aldosterone. An inhibitor of TGF-β1 receptor was used to determine whether the effect of aldosterone on podocytes were mediated through TGF-β1 system. The enzymatic activities of MMP-2 and MMP-9 were assayed by gelatin zymography. Collagen Ⅳ α5 chain and TGF-β1 proteins released into culture supernatants were assessed by Western blot and ELISA analysis. The adhesion rate of podocytes was monitored by flow cytometry. Results Aldosterone increased the activities of MMP-2 and MMP-9 in a dose- and time-dependent manner （P〈0.05）. Aldosterone decreased the level of collagen Ⅳ α5 chain protein in culture supernatants （P〈0.05）. Meanwhile, the expression of TGF-β1 was also increased （P〈0.05）. Spironolactone completely abolished the above-mentioned changes（P〈 0.05）. Blockage of TGF-β1 signaling with SB431542 prevented the aldosterone-induced upregulation of MMP-2 and MMP-9 as well as the downregulation of the collagen Ⅳ α5 chain protein and the adhesion rate of podocytes （P〈0.05）. Conclusions Aldosterone increases the activities of MMP-2 and MMP-9 but decreases the expression of collagen Ⅳ α5 chain and the adhension rate of podocytes possibly via TGF-β1 signaling pathway. Such alterations may contribute to glomerular podocyte injury associated with the GBM abnormality caused by the imbalance between matrix synthesis and degradation.