厄贝沙坦对糖尿病大鼠肾脏骨桥蛋白表达及肾纤维化的影响

目的 探讨不同剂量厄贝沙坦对糖尿病大鼠肾组织骨桥蛋白( OPN)表达及小管间质纤维化的影响.方法 将63只8周龄雄性Wistar大鼠按随机数字表法分为正常对照组(Ctrl组,n=7)、糖尿病组(DM组,n=14)、30 mg/kg肼屈嗪干预组(DM+ Hyd组,n=12)、25mg·kg-1· d-1厄贝沙坦干预组(DM+Irb25组,n=10)、50 mg·kg-1·d-1厄贝沙坦干预组(DM+Irb50组,n=9)和200 mg · kg-1·d-1厄贝沙坦干预组(DM+Irb200组,n=11).糖尿病模型造模成功后4周,灌胃法给予相应剂量的肼屈嗪和厄贝沙坦.第12周末,观察各组大鼠24h尿白蛋白排泄率(UAER)、内生肌酐清除率(Ccr)；PAS及Masson染色观察各组大鼠肾脏病理形态和胶原纤维沉积；ELISA法测定各组大鼠肾组织AngⅡ含量；实时定量PCR检测大鼠肾组织转化生长因子(TGF)β1、OPN mRNA的表达.结果 药物干预各组大鼠UAER、Ccr较DM组显著减少(均P＜ 0.05).DM组大鼠肾小球肥大,系膜基质增生,肾小球及小管间质有大量胶原纤维沉积；药物干预后,肾小球及肾小管上述病变减轻.DM组大鼠肾组织AngⅡ水平及TGF-β1、OPN mRNA表达均显著升高(均P＜0.05),给予肼屈嗪及厄贝沙坦干预后,AngⅡ、TGF-β1、OPN mRNA表达显著降低(均P＜0.05),且随着厄贝沙坦剂量的递增而递减.相关分析结果显示,DM组大鼠肾组织AngⅡ水平与OPN mRNA的表达呈正相关(r=0.74,P＜0.01).结论 厄贝沙坦通过减少肾脏局部AngⅡ水平,进而减少肾脏TGF-β1、OPN mRNA的表达,最终减轻小管间质纤维化,发挥肾脏保护作用,且这种保护作用具有剂量依赖性.

Effect of irbesartan on osteopontin expression and fibrosis in diabetic rat kidney

Objective To explore the effect of different doses of irbesartan on osteopontin expression and fibrosis in diabetic rat kidney. Methods Sixty-three 8-week old male Wistar rat were randomly divided into control group (Ctrl group, n=7), diabetes group(DM group, n=14), 30 mg?kg-1?d-1 hydralazine administrated group(DM+Hyd group, n=12), 25 mg?kg-1?d-1 irbesartan administrated group (DM+Irb25 group, n=10), 50 mg?kg-1?d-1 irbesartan administrated group(DM+Irb50 group, n=9) and 200 mg?kg-1?d-1 irbesartan administrated group (DM+Irb200 group, n=11). Four weeks after modeling, rats were administered with the corresponding dose of irbesartan. After 12 weeks, urinary albumin excretion rate (UAER), endogenous creatinine clearance rate (Ccr) were measured; morphology and collagen deposition in rat kidney were observed by PAS and Masson staining respectively; AngⅡ content in kidney was measured by ELISA; renal tissue TGF-β1 and OPN mRNA expression were detected by real-time PCR. Results UAER and Ccr in the intervention groups of irbesartan were significantly decreased compared with DM group (P<0.05). UAER and Ccr in DM+Irb200 group were significantly lower than those in DM+Irb25 group and DM + Irb50 group (P<0.05). Glomerular hypertrophy, mesangial matrix expansion, tubular lesions and deposition of collagen fiber were siginficant in diabetic rats compared with Ctrl, and prevented after administration with different doses of irbesartan. AngⅡ protein level and TGF-β1, OPN mRNA expression in renal tissue of diabetic rats were significantly higher than those in Ctrl group. AngⅡ, TGF-β1, and OPN mRNA expression was significantly reduced after administration with different doses of irbesartan, and with the increase of irbesartan, the above indicators were decreased P<0.05). Renal local AngⅡ level was positively correlated with OPN mRNA expression (r=0.74, P<0.01). Conclusion Irbesartan reduces renal TGF-β1, OPN mRNA expression by decreasing kidney local AngⅡ in dose-dependent manner, and eventually reduces tubulointerstitial fibrosis, which plays a role in kidney protection.