血管生成素及其Tie 2受体在慢性移植肾肾病大鼠肾组织中的表达及意义

Expressions and effects of angiogenin and its receptor Tie 2 in rat renal allografts undergoing chronic allograft nephropathy

目的探讨慢性移植肾肾病（chronic allograft nephropathy,CAN）大鼠模型的移植肾组织的血管生成素（angiogenin,Ang）及其受体（Tie2）的表达及意义。方法将实验动物分为两组：（1）对照组：供体和受体均为Fisher大鼠,行同种同基因肾移植。（2）实验组：Fisher大鼠为供体,Lewis大鼠为受体,行同种异体肾移植。两组分别于肾移植术后4周、8周和12周各处死3只受体大鼠,采集静脉血及移植肾标本,行血清肌酐、组织学检查,用免疫组织化学（免疫组化）检查和实时定量逆转录聚合酶链反应（reverse transcription polymerase chain reaction,RT-PCR）检测肾组织中Ang1、Ang2及Tie2的表达水平。结果术后8~12周,实验组大鼠的血清肌酐明显升高,移植肾均出现典型的CAN病理改变。免疫组化显示,Ang1和Ang2表达于肾小球和肾脏血管的内皮细胞;Tie2特异表达于肾各级血管的内皮细胞。随着肾移植术后时间的延长,实验组Banff总分逐渐升高,而对照组无异常。对照组术后各时间点肾组织中Ang1、Ang2和Tie2mRNA的表达水平比较差异没有统计学意义,在实验组中术后4周、8周和12周移植肾组织中Ang1、Ang2和Tie2mRNA的表达差异有统计学意义（P〈0.05）。与对照组比较,实验组术后8周、12周的Ang1mRNA表达水平下降,而Ang2mRNA和Tie2mRNA表达水平升高（均为P〈0.05）。结论 Ang及其Tie2的异常表达和平衡失调在CAN的发病机制中可能具有重要的作用,提示对其作进一步的研究将有望为CAN提供新的防治策略。

Objective To investigate the expressions and significance of angiogenin（Ang）and its receptor Tie 2 in rat renal allografts undergoing chronic allograft nephropathy（CAN）.Methods The rats were divided into 2 groups：control group,undergoing homogenic renal transplantation and using Fisher rats as both donors and recipients.Allograft group,undergoing homogeneous renal transplantation and using Fisher and Lewis rats as donors and recipients respectively.At 4,8 and 12 weeks after transplantation,serum creatinine（Scr）was measured and pathologic changes assessed according to the Banff 97 criteria.The mRNA（ΔCT）and protein expressions of Ang 1,Ang 2,and Tie 2 were detected by reverse transcription polymerase chain reaction（RT-PCR）and by immunohistochemistry.Results At 8 and 12 weeks after transplantation,the elevation of Scr and the pathologic changes of CAN were observed in all allografts in the allograft group.The results of immunohistochemistry showed that expressions of Ang 1 and Ang 2 were localized to endothelial cells of glomeruli and renal vessels.Tie 2 was specifically expressed in endothelial cells of all different levels of renal vessels.The Banff score of allograft group gradually increased after renal transplantation but no significant difference was deserved in control group.There were significant differences among different time points in the mRNA expression of Ang 1,Ang 2 and Tie 2 of allograft group（P 0.05）.But there was no significant difference among that of control group（P 0.05）.Compared with control group,the mRNA expression of Ang 1 was decreased and the mRNA expressions of Ang 2 and Tie 2 was increased at 8 and 12 weeks after transplantation（all in P 0.05）.Conclusion The abnormal expression and unblance of Ang and Tie 2 may play important roles in the development of CAN and further study of the underlying mechanism may provide new plan for the prevention and treatment for CAN.