肿瘤坏死因子相关的凋亡诱导配体系统和核因子κB在糖尿病大鼠肾脏中的表达

目的探讨肿瘤坏死因子相关的凋亡诱导配体（TRAIL）系统在糖尿病肾病发生发展中的作用。方法观察TRAIL及其死亡受体4（DR4）、诱骗受体2（DcR2）和核因子KB（NF-KB）在糖尿病大鼠不同时期肾脏中的表达及分析其与肾功能的关系。将80只Wistar大鼠随机分为对照组（NC组）和糖尿病组（DM组），一侧肾切除后，腹腔注射链脲佐菌素（STZ，55mg／kg）建立糖尿病大鼠模型。在第4、8、12、16周末，随机处死各组8只大鼠，收集血液、尿液和肾组织，检测血生化指标、尿蛋白量（24h）和肥大指数等。应用荧光实时定量RT-PCR和免疫组织化学的方法检测肾皮质TRAIL及其受体DR4、DcR2和NF-KB的mRNA和蛋白的表达情况。结果各时间点DM组大鼠尿蛋白量（24h）和肥大指数（肾质量，体质量）均显著高于NC组（P〈0．05）；血白蛋白在第8周末开始显著低于NC组（P〈0．01）；Scr、BUN于第16周末显著高于NC组（P〈0．01）。DM组大鼠TRAIL及其受体DR4mRNA在第4、8及12周末时表达均显著低于NC组（P〈0．01）；第16周末时表达显著高于NC组（P〈0．01）。DM组大鼠DcR2mRNA在第4、8及12周末时表达均显著高于NC组（P〈0．01）；NF-KB的基因表达均显著高于NC组（P〈0．05）。免疫组化结果显示TRAIL及其受体DR4、DcR2主要在肾小管表达，而在肾小球和脉管系统未见表达；NF-KB在肾小球和肾小管均有表达；TRAIL及其受体和NF-KB在各组表达趋势与PCR结果一致。结论TRAIL系统作为调节细胞凋亡的一组重要因子，参与了糖尿病肾病的发生发展。

Expression of TRAIL, DR4, DcR2 and NF-κB in the development of diabetic nephropathy rats

Objective To explore the role of TNF-related apoptosis inducing ligand （TRAIL） system in the pathogenesis of diabetic nephropathy. Methods The expression of TRAIL, death receptor 4(DR4), decoy receptor 2 (DcR2) and nuclear factor-κB （NF-κB） in kidney tissue of diabetic rats in different periods was examined and their relationships with kidney function deterioration were evaluated. Eighty rats were randomly divided as follows: control group (NC), diabetic group (DM). Uninephrectomized male Wistar rats were induced by single intraperitoneal injection of streptozotocin (STZ, 55 mg/kg) in diabetic group. Eight rats were selected randomly from each group at the end of the 4th, 8th, 12th, 16th week of diabetic groups. Serum biochemistry, 24 h urinary protein and the ratio of kidney weight/body weight were determined. Quantitive real time RT-PCR and immunohistochemistry were performed to detect the expression of TRAIL, DR4, DcR2 and NF-κB mRNA and protein. Results DM group showed a higher 24 h urinary protein and hypertrophy index compared with NC group (P<0.05). Blood albumin(Alb) decreased from the 8th week （P<0.01）. BUN and Scr did not change obviously until the 16th week. Compared with NC group, the expression of TRAIL and DR4 decreased significantly at the end of 4th， 8th， 12th week, and increased significantly at the end of 16th week（P<0.01）. DcR2 increased significantly at the end of 4th， 8th， 12th week（P<0.01）. Compared with NC group, the expression of NF-κB increased significantly in diabetic group in every time point（P<0.05）. The protein expressions of TRAIL and its receptors were mainly located in tubuli contorti, and no expression was detectable in the glomeruli or renal vasculature. The expression of NF-κB protein was seen in glomeruli and tubuli contorti. Above expression was significantly related with mononuclear macrophage infiltration, kidney function and structural lesion. The protein expression was consistent with the results of PCR. Conclusion TRAIL system, as important monitoring factors in the regulation of apoptosis, participates in the pathogenesis of diabetic nephropathy.