SnoN蛋白在慢性同种移植肾病大鼠肾组织中的表达及作用

目的：观察Smad核转录共抑因子（SnoN蛋白）在慢性移植肾病（CAN）大鼠肾组织的表达及其与CAN大鼠肾脏功能改变、病理学改变、Smad泛素化调节因子2（Smurf2）之间的关系,探讨SnoN蛋白在CAN中的作用。方法：实验组采用近交系大鼠的同种异基因动物间的左肾原位移植,雄性F344大鼠40只为供体,雄性LEW大鼠40只为受体,移植手术后第10天行右肾切除术,对照组采用单肾切除术的雄性大鼠25只。分别于4周、8周、12周、16周及24周处死大鼠,做肾功能、移植肾组织学检测,并借助免疫组织化学与免疫印迹、逆转录-多聚酶联反应方法检测肾组织中snoN蛋白、snoNmRNA的表达;免疫组织化学与免疫印迹方法检测肾组织smurf2的表达,免疫印迹方法检测肾组织p-smad2/3蛋白的表达水平,逆转录-多聚酶联反应方法检测肾组织TGF-β1mRNA的表达。结果：移植组大鼠尿蛋白定量、血清肌酐水平于移植后16周时显著增高,24周时更为显著。snoN蛋白在移植组逐渐降低,24周时降至最低,为对照组的13%。snoNmRNA在移植组和对照组差异无统计学意义;p-smad2/3、smurf2在移植后随疾病进展逐渐升高,24周时达高峰。免疫组织化学结果显示snoN蛋白表达部位、表达时相与smurf2是一致的。相关分析显示,肾移植大鼠snoN蛋白表达水平与24h尿蛋白定量、血清肌酐水平、肾间质纤维化程度呈负相关（P〈0.05,P〈0.01）。与smad2/3、smurf2水平呈显著负相关（P〈0.01）。结论：SnoN蛋白表达下调在CAN发病机制中起作用,同时Smurf2介导SnoN蛋白降解可能参与了这个过程。

Expression and Role of SnoNprotein on Chronic Allograft Nephropathy

Objective：To investigate expression and role of co-repressor snoN,smad ubiquitination regulatory factor 2（smurf2）on the rat kidney of chronic allograft nephropathy（CAN）model.Methods：The kidney of Fisher（F344）rats were orthotopically transplanted into Lewis recipients.Animals were harvested respectively at 4weeks,8weeks,12weeks,16weeks,24weeks after transplantation for renal fuction and histologycal examination.The expression of snoN was determinated with RT-PCR、Western-blot and immunohistolchemistry assay,while expression of smurf2 was determined by immunohistochemistry and Western-blot.The expression of TGF-β1 was determinated with RT-PCR and the expression of smad2/3 was determined by Western-blot.Results：The expression of snoNprotein was decreased on allograft,while smurf2 protein was increased and the peak of two was at week24 after transplantation,snoN protein expression loss 13% at 24weeks compared with control groups.The expression of snoNmRNA was no difference between experimental groups and control groups.The expression of decreasd snoNprotein were negative correlated with 24-hour urine protein extent、serum creatinine levels in CAN rats,while negative-correlation with smad2/3 in CAN rats.There was also a significant negative-correlation between snoNprotein and smurf2 in CAN rats after transplantation.Conclusion：The decreased of snoNprotein might play a role and through smurf2 dependent degradtion in the mechanism of CAN.