p38丝裂原活化蛋白激酶在糖尿病大鼠肾组织细胞外基质重构中的作用

Effect of phosphorylating-p38 mitogen-activated protein kinase on restructuration of extracellular matrix of diabetic glomeruli

目的探讨糖尿病大鼠肾组织磷酸化p38丝裂原活化蛋白激酶(p38MAPK)及其下游转录因子cAMP反应元件结合蛋白(CREB1)的表达特征及与细胞外基质重构的关系。方法雄性Wistar大鼠60只,行右肾切除术2周后,随机均分为右肾切除对照组(CN组)和糖尿病组(DM组)。DM组腹腔注射链脲佐菌素(STZ)65mg/kg诱发糖尿病模型,并于注射后1、2、4、8、12周各宰取6只大鼠,免疫组化检测肾皮质磷酸化p38MAPK(p p38MAPK)及其磷酸化CREB1(p CREB1)的表达特征,Westernblot检测肾皮质p38MAPK和CREB1磷酸化(活性),RT PCR检测p38MAPK、CREB1和纤维粘连蛋白(FN)mRNA的表达。结果与对照组相比,DM病组p p38MAPK在1、2、4和8周升高,在12周降至正常;p CREB1在2、4和8周增高,在12周时降至正常;FN于4周开始升高。结论早期糖尿病大鼠肾组织中p38MAPK及CREB1的活性升高;p38MAPK途径的激活有可能在糖尿病肾病的细胞外基质重构中发挥一定作用。

Objective To study the expression and significance of the p38 mitogen-activated protein kinase (MAPK) and cAMP-responsive element binding protein (CREB 1) in experimental diabetic mellitus rats, and their relationship with extracllular matrix (ECM) restructuration. Methods Sixty male Wistar rats, with their kidneys removed surgically, were divided in two groups: control group (n=30) and diabetic group (n=30). Diabetic model was reproduced by intraperitoneal injection of Streptozocin (STZ, 65mg/kg). Six rats of each group were sacrificed at 1, 2, 4, 8 and 12weeks after STZ injection. Immunohistochemistry was used to assess the expression of p-p38 MAPK and p-CREB 1 in both control and diabetic groups. Western blot was performed to determine the activity of p-p38 MAPK and p-CREB 1 in both groups. Semiquantitative competitive reverse transcription polymerase chain reaction (PCR) was performed to detect the expression of mRNA of p38 MAPK, CREB 1 and fibronectin (FN). Results Compared with the control group, expression of p-p38 MAPK in diabetic glomeruli was significantly enhanced at 1, 2, 4, and 8 weeks, then it lowered at 12 weeks. P-CREB 1 was increased at 2, 4, 8 weeks, also decreased at 12 weeks. Elevation of FN mRNA began after 4 weeks in diabetic rats. Conclusions Glomerular p38 MAPK activity was increased in early stage of diabetes. This activated p38 MAPK pathway in diabetic glomeruli may in part play a role in the pathogenesis of extracellular matrix restructuring.