巢蛋白在阿霉素肾病模型大鼠肾组织中表达及霉酚酸酯的干预作用

Expression of nestin in renal tissue of rat models of adriamycin nephropathy and the intervention of mycophenolate mofetil

背景:研究证明,足细胞损伤是产生肾小球性蛋白尿的重要机制。而关于足细胞内众多骨架蛋白如何互相调节维持足细胞特有的形态目前尚未完全了解,足细胞骨架的构建和重塑也成为蛋白尿发生机制的研究热点。目的:构建阿霉素微小病变肾病大鼠模型,以霉酚酸酯进行干预,检测大鼠肾组织中巢蛋白(nestin)的表达。方法:纳入雄性Wistar大鼠36只,随机均分为肾病模型组、霉酚酸酯组、正常组(n=12)。肾病模型组、霉酚酸酯组大鼠一次性尾静脉注射阿霉素进行造模,正常组尾静脉注射等量生理盐水。霉酚酸酯组大鼠于造模次日给予霉酚酸酯灌胃,20 mg/(kg·d),1次/d;其他两组大鼠每日给予等量生理盐水。各组分别于造模后14,21,28 d各处死4只大鼠,取肾皮质进行苏木精-伊红染色和免疫组化染色,观察大鼠肾组织病理学改变以及nestin表达情况。结果与结论:正常组大鼠肾小球滤过膜结构完整,上皮细胞足突清晰;肾病模型组大鼠肾小球上皮细胞足突广泛融合,基底膜正常;霉酚酸酯组大鼠肾小球上皮细胞足突部分融合,但病变较轻。免疫组化结果提示从造模第14天开始,肾病模型组和霉酚酸酯组大鼠nestin表达明显增加,与正常组比较差异有显著性意义(P<0.05);霉酚酸酯组大鼠nestin表达低于肾病模型组,差异有显著性意义(P<0.05)。提示肾小球足细胞损伤时,足细胞内nestin表达增多,随病情加重而表达增高。霉酚酸酯可以减轻足细胞损伤,下调nestin的表达,维持足细胞的正常结构,达到延缓肾脏损害的目的。

BACKGROUND： Studies have shown that podocyte injury is an important mechanism to generate glomerular proteinuria. However, it is not yet fully understood regarding the modulation method by which cytoskeletal proteins in the podocyte can maintain the unique morphology of podocytes. The construction and remodeling of podocyte cytoskeleton has become an increasing area of interest in the research field of proteinuria mechanism. OBJECTIVE： To establish rat models of minimal change adriamycin nephropathy, and detect the expression of nestin in rat renal tissue under the intervention of mycophenolate mofetil.METHODS： Thirty-six male Wistar rats were included and randomly divided into nephropathy model, mycophenolate mofetil and normal groups（n=12）. Rats in nephropathy model and mycophenolate mofetil groups were intravenously injected with adriamycin via the tail vein at one time to establish models. Rats in normal group were intravenously injected with the same amount of normal saline via the tail vein. On the next morning, rats in mycophenolate mofetil group were intragastrically administered 20 mg/kg mycophenolate mofetil, once per day. Rats in nephropathy model group and normal group were given the same amount of normal saline daily. Four rats from each group were sacrificed at 14, 21 and 28 days after modeling. The renal cortex was harvested and subjected to hematoxylin-eosin staining and immunohistochemical staining. The pathological changes of renal tissue were observed and nestin expression in renal tissue was detected.RESULTS AND CONCLUSION： In the normal group, rat glomerular filtration membrane structure was complete and epithelial cell foot process was clear. In the nephropathy model group, glomerular epithelial cell foot processes were fused to a large extent, and basement membrane was normal. In the mycophenolate mofetil group, glomerular epithelial cell foot processes were partly fused, but the pathological changes were milder. Immunohistochemistry results showed that beginning from the 14^th day of modeling, rat nestin expression in the nephropathy model and mycophenolate mofetil groups was significantly increased compared with the normal group（P 〈0.05）. Rat nestin expression in the mycophenolate mofetil group was significantly lower than that in the nephropathy model group（P 〉0.05）. These results suggest that after glomerular podocyte injury, nestin expression in podocyte increased, while the expression increased with the aggravation of the disease. Mycophenolate mofetil can alleviate podocyte injury, downregulate nestin expression, maintain the normal structure of podocytes, and thereby achieve the purpose of delaying kidney damage.