洛沙坦对糖尿病大鼠肾组织一氧化氮水平的影响

Effect of losartan on the level of nitric oxide in renal tissue of diabetic rats

目的 研究洛沙坦对糖尿病大鼠肾组织一氧化氮（NO）水平的影响。方法 雄性Wistar大鼠分为3组,A组（11只）为正常对照组,B组（11只）为糖尿病未干预组,C组（9只）为糖尿病大鼠洛沙坦干预组。以链脲菌素制备糖尿病大鼠模型,大鼠饲养18周后取出肾脏检测诱导型NO合成酶（iNOS）mRNA的表达,电镜检测大鼠肾小球基底膜厚度及系膜基质密度（系膜基质面积/系膜面积）。收集24h尿测定尿白蛋白排泄（UAE）及肌酐,并心脏内取血检测血肌酐。mRNA表达采用RT-PCR,以β-actin作为内对照。UAE测定采用大鼠白蛋白特异的酶免疫分析试剂盒。结果 肾组织iNOSmRNA表达在B组大鼠（0.30±0.12）显著高于A组（0.12±0.04,P<0.01）,C组（0.25±0.14）与B组比较差异无显著性意义（P>0.05）。肾组织NO水平在B组大鼠[（0.56±0.20）μmol/mg肾组织]显著低于A组[（1.05±0.25）μmol/mg肾组织]和C组[（1.13±0.62）μmol/mg肾组织,P均<0.01]。UAE在B组大鼠[（2.18±1.98）mg/d]显著高于A组[（0.41±0.47）mg/d]和C组[（0.65±0.89）mg/d,P均<0.05]。肌酥清除率在B组大鼠[（19.75±9.60）ml/d]显著低于A组[（59.63±22.75）ml/d]和C组[（40.88±25.57）ml/d,P均<0.05]。基底膜厚度在B组大鼠[（531.6±107.6）nm]显著高于A组[（312.

Objective To investigate the effect of losartan on inducible nitric oxide synthase (iNOS) and nitric oxide (NO) in diabetic renal tissue of rats. Methods Male Wistar rats were divided into 3 groups, group A( n = 11) : control; group B( n = 11) : without any therapy, and group C( n = 9) : treated with losartan. Diabetic models were made by the intraperitoneal injection of streptozotocin. At the end of the 18th week, kidneys were taken out from all the rats to measure the local level of NO and the expression of iNOS mRNA by RT-PCR with the p-actin as the internal control. Also, glomerular basement membrane (BM) thickening and mesangial matrix (MM) density (MM area/mesangial area) of kidneys were observed by electronic microscope. At the same time, blood was drawn from the heart to measure the level of creatinine, and 24-hour urine was collected to measure the level of creatinine and albumin (urine albumin excretion, UAE) by rat albumin enzyme immunoassay kit. Results The expression of renal iNOS mRNA in group B (0. 30±0. 12) was significantly higher than that in group A (0. 12±0. 04, P < 0. 01), and showed no difference between group C(0. 25±0. 14) and group B ( P > 0. 05) . The level of renal NO in group B [(0. 56 ±0. 20)umol/mg]was significantly lower than that in group A[ (1. 05±0. 25)umol/mg]and group C[(l.13 ±0.62)umol/mg, both P <0.01] . UAE in group B[ (2. 18 ± 1. 98) mg/d] was significantly higher than that in group A [(0.41 ±0. 47)mg/d]and group C [(0.65±0. 89)mg/d,both P < 0. 05]. The clearance of creatinine in group B [(19. 75 ± 9. 60) ml/d] was significantly lower than that in group A [(59.63±22. 75) ml/d] and group C[(40. 88±25. 57)ml/d .both P <0.05].GBM thickening in group B [(531. 6±107. 6) nm] was significantly higher than that in group A [(312.4±25.4) nm] and group C [ (316. 6± 33. 3)nm,both P < 0. 05]. MM density in group B(56. 41± 6. 78) was significantly higher than that in group A(33. 95 ±5. 22), and group C (35. 37±6. 70, both P < 0. 05) . Conclusions The NO level is decreased significantly, however, the expression of iNOS mRNA is increased significantly in diabetic rat kidneys. Losartan can prevent the development of diabetic nephropathy (DN), and also increase the NO level, but can not change the expression of iNOS mRNA in diabetic rat kidneys.