晚期糖基化终产物对心肌细胞葡萄糖转运蛋白4表达的影响及p38丝裂原活化蛋白激酶作用的研究

Effects of advanced glycation end products on the expression of glucose transporter 4 in cardiomyocytes and the involvement of p38 mitogen-activated protein kinase

目的通过建立胰岛素抵抗模型,探讨晚期糖基化终产物(AGEs)对SD大鼠乳鼠心肌细胞葡萄糖转运蛋白4(GLUT4)表达的影响,以及p38丝裂原活化蛋白激酶(MAPK)在此过程中的作用。方法采用酶消化法原代培养SD大鼠乳鼠心肌细胞,建立胰岛素抵抗模型,给予不同干预,分为胰岛素抵抗对照组、牛血清白蛋白(BSA)组、糖化白蛋白(AGE-BSA)组,p38MAPK抑制剂SB203580+AGE-BSA组,用实时荧光定量聚合酶链反应(PCR)和蛋白质印迹法检测GLUT4和p38MAPK的蛋白及m RNA表达水平。结果胰岛素抵抗心肌细胞有GLUT4表达,其中对照组与BSA组比较差异无统计学意义(P>0.05),AGE-BSA可诱导GLUT4表达降低,且呈浓度依赖性,AGE-BSA组与对照组比较差异有统计学意义(P<0.05)。但在阻断p38MAPK途径后表达量明显上升(P<0.05),对照组与BSA组比较,p38MAPK磷酸化水平差异无统计学意义(P>0.05),AGE-BSA可导致p38MAPK磷酸化的增加,也呈浓度依赖性,AGE-BSA组与对照组比较差异有统计学意义(P<0.05)。结论 AGEs可诱导胰岛素抵抗心肌细胞GLUT4 m RNA和蛋白表达降低,此过程与p38-MAPK磷酸化增加有关。

Objective To investigate the effects of advanced glycation end-products（AGEs） on the expression of glucose transporter 4（GLUT4） in neonatal rat cardiomyocytemodel of insulin resistanceand the involvement of p38 mitogen-activated protein kinase（p38 MAPK） in this process. Methods SD rat neonatal cardiomyocytes were cultured by enzyme digestion and used for establishing the insulin resistance model. The cardiomyocytes were divided into different groups based on varied interventions： the insulin resistance control group, bovine serum albumin（BSA） group, AGE-BSA induced group, and p38 MAPK inhibitor SB203580 ＋AGE-BSA induced group. Real-time PCR and Western blotting were used to detect the protein and mRNA expression levels of GLUT4 and p38 MAPK.Results GLUT4 was expressed in insulin-resistant myocardial cells, with no significant difference between the control and BSA groups（P〉0.05）. AGE-BSA could induce lowered GLUT4 expression in a concentration-dependent manner, with statistically significant difference between AGE-BSA induced group and control group（P〈0.05）. However, the GLUT4 expression in the AGE-BSA induced group was significantly increased after blockade of the p38 MAPK pathway（P〈0.05）. While there was no significant difference in the phosphorylation level of p38 MAPK between the control group and the BSA group（P〉0.05）, AGE-BSA may result in increased p38 MAPK phosphorylation in a concentration-dependent manner, responsible for the statistical difference between AGE-BSA induced group and control group（P〈0.05）. Conclusion AGEs may induce a reduction in GLUT4 mRNA and protein expression in insulin-resistant cardiomyocytes, which is associated with increased phosphorylation of p38-MAPK during this process.