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目的:观察单侧肾动脉狭窄(RAS)大鼠模型慢性肾缺血组织中肾小管-间质a-平滑肌肌动蛋白(a-SMA)的表达和意义。 方法:建立Goldblatt单侧RAS大鼠模型,观察大鼠慢性缺血肾脏在90天内不同阶段的病理改变;应用免疫组化法检测肾小管-间质a-SMA及波形蛋白(vimentin)在不同时间点的表达;应用免疫荧光双标记激光共聚焦显微镜观察细胞角蛋白(cytokeratin,CK)与a-SMA在肾小管上皮细胞中的共定位情况。 结果:RAS术后第5天首先出现肾小管vimentin阳性,术后第7天肾间质可见少量的a-SMA阳性细胞并随时间递增。通过连续切片观察到,vimentin阳性的肾小管周围肾间质细胞a-SMA表达增强,并与肾小管间质纤维化程度基本一致。当慢性缺血状态持续存在时,后期(术后第45天至90天)少数损伤的肾小管上皮细胞表达a-SMA。应用免疫荧光双标记激光共聚焦显微镜观察发现,部分a-SMA阳性的肾小管上皮细胞同时表达CK,并且个别细胞还有向间质游走的趋势。 结论:在慢性肾缺血早期Vimentin阳性的肾小管上皮细胞本身可能诱导了肾间质固有细胞发生肌成纤维细胞转分化,参与肾间质纤维化的发生和发展;在慢性肾缺血后期,肾小管上皮细胞转分化可能是导致肾纤维化进行性发展的关键环节。
Objective: To observe the expression and significance of a-smooth muscle actin (a-SMA) in renal tissue from rat with unilateral renal artery stenosis (RAS). Methods: The unilateral Rb rat model of Goldblatt was established to observe the pathological changes in different stages of chronic ischemic kidneys in 90 days. The expressions of a-SMA and vimentin in tubulointerstitium were detected by immunohistochemistry at different time The co-localization of cytokeratin (CK) and a-SMA in renal tubular epithelial cells was observed by immunofluorescence double labeling laser confocal microscopy. Results: On the fifth day after RAS, tubules were initially positive for vimentin. A small amount of a-SMA positive cells were seen in the renal interstitium on the 7th day after operation and increased with time. By serial sections, vimentin-positive renal tubular interstitial a-SMA expression increased, and with the degree of tubulointerstitial fibrosis is basically the same. A small number of injured renal tubular epithelial cells express a-SMA in the late phase (45 days to 90 days after surgery) when the chronic ischemic condition persists. Immunofluorescence double-labeled laser confocal microscopy showed that some a-SMA-positive tubular epithelial cells express CK at the same time, and some cells also have the tendency to migrate to the stroma. Conclusion: Vimentin-positive tubular epithelial cells in early stage of chronic renal ischemia may induce myofibroblast transdifferentiation in renal interstitial innate cells and participate in the occurrence and development of renal interstitial fibrosis. In the late stage of chronic renal ischemia, Transdifferentiation of renal tubular epithelial cells may lead to the progressive development of renal fibrosis, a key link.