尾加压素Ⅱ和组织型转谷氨酰胺酶在大鼠肾间质纤维化组织中的表达及意义

Expressions of urotensin Ⅱ and tissue transglutaminase in rat renal interstitial fibrosis tissue and their significances

目的:探讨尾加压素Ⅱ(UⅡ)和组织型转谷氨酰胺酶(tTG)在大鼠肾间质纤维化组织中的表达及意义,为进一步明确UⅡ致纤维化的机制提供实验依据。方法:雄性Wistar大鼠随机分为假手术组(n=8)和模型组(n=8),采用左侧输尿管结扎术制备肾间质纤维化模型。术后第2周末处死各组大鼠。采用HE和Masson染色观察肾组织病理学改变;采用免疫组化法检测肾间质中UⅡ、tTG和纤维连接蛋白(FN)的表达;采用RT-PCR技术检测UⅡ和tTG mRNA的表达水平。结果:HE和Masson染色可见,模型组大鼠肾间质增宽,胶原纤维明显增生。免疫组化显示,假手术组大鼠UⅡ、tTG和FN在肾小管、肾间质区有少量表达,肾小球内除UⅡ有微量表达外,tTG和FN无阳性表达;模型组大鼠UⅡ、tTG和FN在肾小管和肾间质区的表达信号较假手术组明显增强(P<0.01),模型组大鼠UⅡ的蛋白表达与FN的蛋白表达呈正相关关系(r=0.724,P<0.05)。模型组UⅡ和tTG的基因表达明显高于假手术组(P<0.05),模型组大鼠肾内UⅡ基因和蛋白表达与tTG基因和蛋白表达均呈正相关关系(r=0.647,P<0.05;r=0.787,P<0.01)。结论:UⅡ和tTG可能共同参与肾间质纤维化,UⅡ的致纤维化作用可能部分是通过tTG的活化而实现的。

Objective To investigate the expressions of urotensin Ⅱ（UⅡ） and tissue transglutaminase（tTG） in rat renal fibrosis tissue and their significances,and provide experimental basis for further study on the mechanism of UⅡ-indced fibrosis.Methods The male Wistar rats were randomly divided into sham operation group（n=8） and model group（n=8）.The models were established by unilateral ureteral obstruction（UUO） method.The rats were sacrificed at day 14.The histological changes in renal tubular interstitium were observed by HE and Masson staining,and the mRNA and protein levels of UⅡ,tTG and fibronectin（FN） were detected by RT-PCR and immunohistochemistry.Results The Masson and HE staining results showed interstitial widening and obvious proliferation of collagen fibers in model group.The immunohistochemistry results showed weak signals of UⅡ,tTG and FN in renal tubular cells and tubulointerstitium,and very rare positive signals except UⅡin the glomeruli in sham operation group.Compared with sham operation group,the expressions of UⅡ,tTG and FN in model group were significantly increased（P〈0.01） and the level of UⅡ protein had positive correlation with the level of FN protein（r=0.724,P〈0.05）.The levels of UⅡ mRNA and protein had positive correlation with the levels of tTG mRNA（r=0.647,P〈0.05） and protein（r=0.787,P〈0.01）.Conclusion Both UⅡand tTG may play an important role in the pathogensis of renal tubulointerstitial fibrosis,and UⅡmay promote the development of fibrosis partially via activation of tTG.