5/6肾切除大鼠残肾细胞凋亡的信号途径研究

Proapoptotic signaling pathway in kidneys of rats with 5/6 nephrectomy

目的研究细胞凋亡及凋亡信号途径在5/6肾切除(SNx)中的作用及机制。方法复制5/6肾切除大鼠模型,在1、2、4、8、12、16、26和40周,用原位末端标记法、免疫组化、RT-PCR、Western-blot分别检测细胞凋亡、caspase-3,-8,-9的mRNA和蛋白质的水平。结果模型组出现肾小球硬化和肾间质纤维化,肾小球、肾小管和肾间质的细胞凋亡数明显高于对照组(P<0.05,P<0.01);caspase-3,-8,-9的mRNA和蛋白质的变化趋势一致,与对照组比较病变过程中呈波浪式上调,高峰分别在4周和40周(P<0.05),caspase-9的增长幅度明显高于caspase-8。结论5/6肾切除大鼠的疾病进展与肾小球、肾小管和肾间质的细胞凋亡有关,死亡受体和线粒体信号途径均参与其中,线粒体信号途径起主要作用。

[Objective] To investigate the signaling pathways of apoptosis in the model of subtotal nephrectomy （SNx）. [Methods] Remnant kidneys were produced in adult male SD rats by 5/6 nephrectomy. The renal function and histopathological changes were evaluated at 1,2,4,8,12,16,26 and 40 weeks after operation finished. The tissues of remnant kidneys were used to detect apoptosis cells by in sltu end-labeling of cleaved DNA （TUNEL）. The expression of easepase-3, casepase-8 and casepase-9 by RT-PCR and Western-blot. The proteins were detected by immunohistochemistry staining. [Results] The results showed the characterlstle of renal pathology dynamic change in 5/6 nephrectomy remnant kidney： tubule-interstitial inflammation and fibrosis, as well as glomerulosclerosis. Apoptosis was increased and most of apoptosis cells were detected in tubular epithelial cells and interstitial area. The mRNA and protein expression of easepase-3, casepase-8 and casepase-9 were increased in all courses, and peaked at week 4 and 40. Caspase-8 revealed 1.9 fold increase after 4 weeks and 1.8 fold increase after 40 weeks. Caspase-9 showed 3.9 fold and 3.3 fold increased＇ in the same time. [Conclusion] Apoptosis plays the important role in chronic glomerulosclerosis, tubule atrophy and interstitial fibrosis in 5/6 nephrectomy. These results indicate that subtotal nephrectomy evokes death-recepator pathway and mitochondrial pathway, the main signaling pathways is mitochondrial apoptotic pathways rather than death receptor pathways.