罗格列酮延缓慢性肾病进展的机制研究

Mechanism of Rosiglitazone on Delaying the Progress of Chronic Kidney Disease

目的探讨过氧化物酶体增殖物激活受体γ(PPARγ)激动药罗格列酮对5/6肾切除肾衰竭大鼠的肾脏保护作用及可能作用机制。方法选用180～200 g健康雄性SD大鼠建立5/6肾切除肾衰竭模型,分为假手术组、模型对照组和罗格列酮组。第12周时采用断头法处死大鼠,并检测各组大鼠血清尿素氮、肌酐及24 h尿蛋白水平;取残余肾组织行病理检查,判断肾小球硬化、肾小管间质损伤程度;采用免疫组化方法观察PPARγ和神经型一氧化氮合酶(nNOS)在肾脏组织的分布;利用RT-PCR和Western Blot检测PPARγ和nNOS蛋白和mRNA的表达水平。结果与假手术组比较,模型对照组和罗格列酮组大鼠24 h尿蛋白、血清尿素氮及肌酐均显著升高(P<0.01);但与模型对照组比较,罗格列酮组各指标则明显降低(P<0.05)。病理学检查示模型对照组大鼠肾组织有明显的肾小球硬化及肾小管间质损伤,肾小球硬化指数及肾小管间质损伤指数均较假手术组明显增高(P<0.01);而罗格列酮组上述指标则较模型对照组明显降低(P<0.05)。免疫组化结果显示5/6肾切除大鼠PPARγ主要分布在肾小管上皮细胞、系膜细胞和浸润的巨噬细胞,nNOS主要定位在致密斑,内髓集合管也有表达。模型对照组PPARγ、nNOS蛋白和mRNA的表达较假手术组明显下降(P<0.05),而罗格列酮组PPARγ和nNOS的表达则较模型对照组明显升高(P<0.05)。结论大鼠5/6肾切除后,给予罗格列酮可以明显减轻肾小球硬化和肾间质纤维化的程度,其作用机制可能与其上调PPARγ和nNOS基因的表达有关,且有明显的相关性。

Objective To investigate the protective effects of PPARγ antagonist rosiglitazone on kidney and the possible mechanism in 5/6 nephrectomy rats with renal failure.Methods SD male rats,weighting 180-200 g,were randomly divided into sham-operation group,model group and rosiglitazone group.After 12 weeks,the rats were killed with decapitation method,and serum urea nitrogen,creatinine and 24 h urinary protein were detected.Residual kidney tissues were pathologically examined to determine glomerular sclerosis and tubulointerstitial injury.The distribution of PPARγ and nNOS in the kidney tissues was detected by immunohistochemistry.RT-PCR and Western Blot were used to detect the mRNA expression of PPARγ and nNOS.Results 24 h urine protein,serum urea nitrogen and creatinine of rats in the model and rosiglitazone groups were significantly higher than those in the sham-operation group（P〈0.01） and osiglitazone group than in model group（P〈0.05）;and these indicators were significantly lower in rosiglitazone group than in model group（P〈0.05）;The renal glomerular sclerosis and tubulointerstitial damage,glomerular sclerosis index and tubulointerstitial damage index in model group were significantly higher than those in sham-operation group（P〈0.01）;and these indexes were significantly lower in rosiglitazone group than in model group（P〈0.05）.Immunohistochemistry showed that PPARγ mainly distributed in renal tubular epithelial cells,mesangial cells and infiltrating macrophages of the 5/6 nephrectomy rats.nNOS of cortex was mainly localized in dense patches,and also expressed in inner medullary collecting duct.As compared with the sham-operation group,the protein and mRNA expression of PPARγ and nNOS was significantly decreased in model group（P〈0.05）,while the expression levels of PPARγ and nNOS in rosiglitazone group were significantly higher than those in model group（P〈0.05）.Conclusion Rosiglitazone can significantly reduce glomerulosclerosis and the degree of renal interstitial fibrosis in the 5/6 nephrectomy rats,and its mechanism may be related to increased gene expression of PPARγ and nNOS.