糖尿病大鼠肾组织Smurf2表达及其与SnoN蛋白降解的关系  

Expression of Smurf 2 in kidney of diabetic rats and its relationship with downregulation of SnoN

作　　者：刘瑞霞[1] 郭兵[1] 肖瑛[1] 石明隽[1] 王圆圆[1] 桂华珍[1] 张国忠[1] 

机构地区：[1]贵阳医学院病理生理学教研室,贵州贵阳550004

出　　处：《中国病理生理杂志》2010年第9期1743-1748,共6页Chinese Journal of Pathophysiology

基　　金：贵州省科技攻关资助项目(No黔科字S[2007]1033号);贵州省高层次人才科研条件特助经费资助项目(NoTZJF-2007年-44号);贵州省科技基金资助项目(No黔科合J字[2008]2167号);贵阳医学院2009年研究生教育创新基地专项经费(NoB200903)

摘　　要：目的:观察Smad泛素化调节因子2(Smurf2)和核转录共抑制因子SnoN在糖尿病(DM)大鼠肾组织的动态表达,并初步探讨Smurf2在DM大鼠肾组织SnoN蛋白表达变化中的作用。方法:链脲佐菌素(STZ)尾静脉注射复制DM大鼠模型,随机分为DM2、4、8、12、16和24周组,每组均设鼠龄匹配的正常对照组(n=6)。生化方法测血糖、血肌酐(Scr)及24h尿蛋白量,计算肾脏指数;HE染色观察胰腺和肾组织病理学改变;免疫荧光染色检测胰腺组织胰岛素、肾组织Smurf2和SnoN的表达;Westernblotting检测肾皮质Smurf2、SnoN、转化生长因子β1(TGF-β1)和磷酸化Smad2(p-Smad2)蛋白的表达;RT-PCR检测肾皮质Smurf2和SnoN的mRNA。结果:(1)DM各组血糖、血Scr、24h尿蛋白量和肾脏指数均高于正常对照组,正常胰腺组织胰岛素表达强,DM大鼠胰岛素表达则明显减弱;(2)Smurf2和SnoN蛋白均主要表达于肾小管上皮细胞,从DM2周始各DM组Smurf2、TGF-β1和p-Smad2蛋白表达均多于正常对照组,DM4周起各DM组SnoN蛋白均少于正常对照组,DM各组SnoNmRNA与正常组相比无显著差异,Smurf2mRNA随病程进展逐渐增多;(3)Smurf2和SnoN蛋白的表达量呈显著负相关(r=-0.88,P<0.01)。结论:在糖尿病肾病发病过程中SnoN蛋白的表达减少可能与Smurf2介导其泛素化降解有关。AIM： To investigate the expression of Smad ubiquitin regulatory factor 2 （ Smurf 2） and transcription co-repressor Ski-related protein N （ SnoN） in renal tissues of diabetic rats,and to explore the effect of the E3 ubiquitin ligase Smurf 2 on the protein level of SnoN. METHODS： The rat model of diabetes was induced by vena caudalis injection of streptozotocin （ STZ） . The rats were killed at week 2,4,8,12,16,and 24 after injection of STZ. Meanwhile, the age-matched rats without any treatment served as normal controls （ n = 6） . The blood glucose,serum creatinine （ Scr） and 24-hour urine protein were examined by biochemical method. The kidney index of the rats was also measured. The pathological changes of the pancreatic and renal tissues were stained with HE and observed under microscope. The expression levels of insulin,Smurf 2,SnoN,TGF-β1 and phosphorylation of Smad2 were determined by immunofluorescence staining and/or Western blotting. The mRNA expression of Smurf 2 and SnoN in renal cortex was examined by RT-PCR. RESULTS： Compared with the control animals,the blood glucose,24-hour urine protein,Scr and kidney index increased remarkably in diabetic rats. The expression of insulin in control groups was strong,whereas that in diabetic groups was weak. The proteins of Smurf 2 and SnoN detected by immunofluorescence staining were located in the renal tubules. The protein levels of TGF-β1,Smurf 2 and p-Smad2 were significantly up-regulated in diabetic rats. The renal SnoN protein of diabetic rats at the time point of week 2 was the same as that of the normal rats; however,a significant decrease was observed from the time point of week 4 after DM induction. No significant difference of SnoN mRNA level was observed between normal and diabetes groups at all time points. The mRNA level of Smurf 2 was gradually up-regulated in the diabetic rats. CONCLUSION： Downregulation of SnoN protein in renal tissues of diabetic rats may be mediated by Smurf 2.

关 键 词：Smad泛素化调节因子2 SNON 磷酸化Smad2 糖尿病肾病 

分 类 号：R363[医药卫生—病理学]