目的:研究GLP-1对糖基化终末产物(AGEs)引起人近端肾小管上皮细胞(HK-2细胞)损伤的影响及机制.方法:将HK-2细胞分成4组:正常对照组,AGEs处理组,AGEs+GLP-1处理组和AGEs+Insulin处理组,分别培养24h.检测各组细胞对荧光标记白蛋白的吸收能力.结果:与正常组相比,AGEs处理组细胞吸收白蛋白的能力减弱,与重吸收相关的通道蛋白Megalin和Cubilin表达降低.AGEs+GLP-1处理组细胞吸收白蛋白的能力与正常对照组相似,给予胰岛素无明显保护作用,与AGEs处理组无差别.进一步研究发现,AGEs处理组较正常对照组的PKA表达降低,PKC表达升高;同时诱导型一氧化氮合酶(iNOS)升高,超氧化物歧化酶(SOD)降低.给予GLP-1可减轻AGEs的作用.采用信号通路激活剂或阻断剂后发现,抑制PKA或激活PKC可以拮抗GLP-1对iNOS和SOD的调节作用.结论:GLP-1可能通过调节PKA和PKC水平降低AGEs引起的肾小管上皮细胞氧化应激,从而维持通道蛋白的表达,改善细胞对白蛋白的重吸收功能.%Objective:To explore the effects of GLP-1 on AGEs-induced injury of human proximal tubular epithelial (HK-2)cells and its mechanism.Methods:HK-2 cells were divided into four groups:normal group cultured in M199 medium containing 5％ FCS,AGEs group cultured in medium supplied with AGEs;AGEs+ GLP-1 group cultured in medium supplied with both AGEs and GLP-1;and AGEs+Insulin group cultured in medium supplied with both AGEs and Insulin.Albumin absorbabiligy of HK-2 cells was detected by measuring the fluorescence intensity.Results:Compared with normal group,the absorption of albumin was decreased in AGEs group,and megalin as well as cubilin were also down-regulated.In AGEs+GLP-1 group,the albumin absorption,megalin and cubilin level were similar to normal group.However,there were no difference between AGEs+Insulin group and AGEs group.Compared with normal group,AGEs treatment down-regulating PKA and up-regulating PKC,accompanied with high iNOS and low SOD levels.This indicated oxidative stress occurred.Treated with GLP-1 but not insulin could inhibit the effect of AGEs.But the action of GLP-1 on the expression of iNOS and SOD could be blocked by PKA inhibitor or PKC activator.Conclusion:GLP-1 might alleviate oxidative stress on renal tubular epithelial cells by regulating PKA/PKC,which maintained the expression of megalin and cubilin,then improved the re-absorption function of renal tubular epithelial cells
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