自噬和ASPPs在老年大鼠急性肾损伤早期的表达

目的观察自噬相关蛋白和p53凋亡刺激蛋白(ASPPs)在肾损伤早期的表达变化，初步探讨自噬相关蛋白和ASPPs是否可能成为老年大鼠AKI早期生物标志物。 方法建立顺铂致AKI青年与老年大鼠模型。雄性SD老年大鼠随机分为假手术组(Sham)，顺铂模型组，同时设数量匹配的雄性SD青年大鼠为对照；模型组大鼠一次性腹腔注射顺铂4 mg/kg，Sham组相同途径注射生理盐水4 ml/kg；在给药12 h、1 d、3 d、5 d、7 d时检测大鼠Scr、BUN；光镜观察大鼠肾脏病理变化；透射电镜观察大鼠肾小管上皮细胞超微结构变化及自噬体的情况；免疫印迹法检测肾脏组织Beclin 1、溶酶体相关膜蛋白2(LAMP2)、p62、p53及ASPP抑制物(iASPP)和ASPP1表达情况。 结果顺铂诱导12 h后，与Sham组比较，青年与老年大鼠Scr无明显变化(P>0.05)；电镜观察到大鼠肾小管上皮细胞自噬体出现而且数量显著增多；老年大鼠肾组织Beclin 1、p62、LAMP-2和p53表达水平明显升高(P<0.05)，iASPP表达水平明显降低(P<0.05)，并且老年大鼠肾组织Beclin 1、LAMP-2和p53变化时间早于青年大鼠(P<0.05)。 结论自噬和ASPPs在老年大鼠AKI发生早期即可出现，在Scr开始升高前，反应性自噬已经启动。自噬相关蛋白和ASPPs有望成为AKI早期的损伤标志物，可能是AKI早期干预的新靶点，但仍需更深入的研究。

Expression of autophagy and ASPPs in early acute kidney injury of aged rats

ObjectiveTo observe the expression changes of autophagy-related proteins and apoptosis-stimulating proteins of p53 (ASPPs) in early renal injury, and to explore whether autophagy-related proteins and ASPPs may become early biomarkers of acute kidney injury (AKI) in aged rats. MethodsA cisplatin-induced AKI model was established in both young and old rats. Male SD rats were randomly divided into sham operation group and cisplatin model group, and a matched number of male young SD rats were as controls. Rats in the model group were given intraperitoneal injection of cisplatin 4 ml/kg, while rats in the sham group injected with normal saline 4 mg/kg. Rats were examined for Scr and BUN at 12 h, 1 day, 3 days, 5 days, and 7 days, and the pathological changes of rat kidney were observed by light microscopy. Ultrastructural changes and autophagosomes in rat renal tubular epithelial cells were observed under transmission electron microscopy. Western blotting was used to detect the expression of Beclin 1, LAMP-2, p62, p53, iASPP and ASPP1 in kidney tissues. ResultsAfter 12 hours of cisplatin induction, compared with the sham group, there was no significant change in Scr of young and old rats (P>0.05), and electron microscopy showed that autophagosomes in rat renal tubular epithelial cells appeared and the number increased significantly. The expression levels of Beclin 1, p62, LAMP-2, and p53 in the kidney of aged rats were significantly increased (P<0.05), with the expression level of iASPP being significantly decreased (P<0.05). And the renal expression of Beclin 1, LAMP-2, and p53 changed earlier in the old rats than in the young rats (P<0.05). ConclusionsAutophagy and ASPPs appeared in the early stage of rat AKI, and reactive autophagy had started before Scr began to rise. Autophagy-associated proteins and ASPPs are expected to be earlier markers of AKI, and may be new targets for early intervention of AKI, which still need further research.