洛伐他汀对糖尿病大鼠肾功能及肾脏组织p38丝裂原激活蛋白激酶表达的影响

Effects of lovastatin on renal function and expression of phosphorylating -p38 mitogen-activated protein kinase in experimental diabetic nephropathy in rats

目的 探讨洛伐他汀对糖尿病(DM)大鼠肾小球结构、功能及肾组织p38丝裂原活化蛋白激酶(MAPK)及其下游转录因子cAMP反应元件结合蛋白(cREB)表达的影响。方法 18只雄性Wistar大鼠行右肾切除术2周后,随机分为3组:右肾切除对照组、DM组和洛伐他汀治疗组每组6只。DM组和洛伐他汀组腹腔注射链脲佐菌素(STZ,65 mg／kg)诱发DM模型,洛伐他汀组制模后1 d每日给予洛伐他汀20 mg／kg灌胃。分别于注射STZ后4周收集大鼠尿液,测定尿蛋白(Upro)、尿肌酐(UCr);股动脉放血分离血清,测定血糖(Glu)、血肌酐(SCr)、尿素氮(BUN)、胆固醇(CHO)和甘油三酯(TG),并计算肌酐清除率(CCr)。免疫组化检测肾皮质磷酸化p38 MAPK(P-p38 MAPK)及磷酸化CREB(P-CREB)的表达特征,并检测转化生长因子-β1(TGF-β1)、纤维粘连蛋白(FN)及层粘连蛋白(LN)的表达,应用图像分析系统进行定量分析。流式细胞术检测P-p38 MAPK和P-CREB蛋白的表达,Western印迹法检测肾皮质P-p38 MAPK和P-CREB活性的变化。结果 与对照组相比,4周时DM组P-p38 MAPK、P-CREB、TGF-β1、FN及LN表达均明显升高(P均<0.01);而与DM组相比,洛伐他汀组各指标的表达有不同程度的降低(P均<0.01)。结论 洛伐他汀对DM大鼠肾脏结构和功能具有保护作用,可能通过调节p38

Objective To investigate the effects of lovastatin on renal function, activity and expression of the p38 mitogen-activated protein kinase (MAPK) and cAMP responsive element - binding protein (CREB) in experimental diabetic nephropathy in rats. Methods Eighteen uninephrectomized male Wistar rats were randomly divided into three groups: control(n=6), diabetic(n=6) and lovastatin treatment group (n=6). Diabetes was induced by intraperitoneal injection of STZ(65 mg/kg). Lovastatin (20 mg/kg) was administered daily by gavage from the next day of the induction diabetes for 4 weeks. Four weeks later, animals were sacrificed and samples were collected to determine various parameters, including protein and creatinine in urine(Upro and UCr), and glucose (Glu ), creatinine (SCr) , blood urea nitrogen (BUN ) in serum. Immunohistochemistry and computer image - pattern analysis system were used to analyze activation of P - p38 MAPK and P-CREB, the expression of transferase growth factor-β1 (TGF-β1) , fibronectin (FN), laminin(LN) in renal glomeruli were also measured. Results Expression of P- p38 MAPK and P - CREB in diabetic glomeruli in diabetic rats were higher than the controls, the same as the expression of TNF-β1, FN, LN(all P<0. 01). After lovstatin treatment, expression of P - p38 MAPK, P-CREB and TGF-β1, FN, LN were markedly decreased compared with diabetic group (all P<0. 01). Conclusion Inhibition of glomerular p38 MAPK signal transduction pathyway may be responsible for the decrement of extracellular matrix accumulation and renal protective effects of lovastatin in uninephrectomized rats.