中文摘要：

目的研究微小RNA．21（miR-21）持续上调在马兜铃酸急性肾损伤后肾小管间质纤维化发生中的作用及其相关机制。方法给予C57BL／6J小鼠一次性腹腔注射马兜铃酸（10mg／kg），构建马兜铃酸急性肾损伤模型。分别在给药后第1、3、7、14、28天处死小鼠，留取血和肾组织标本。实验组小鼠于马兜铃酸给药前1h、给药后第5、10天分别经尾静脉给予anti-miR-21或anti-scramble（10mgCkg）。HE染色及Masson染色法观察肾脏病理改变；实时定量PCR法检测肾组织miR-21mRNA表达；Western印迹和免疫组化法检测。肾组织α平滑肌肌动蛋白（α—SMA）、波形蛋白（Vimentin）、I型胶原蛋白（Collagen I）及钙黏蛋白（E-Cadherin）的表达变化。结果马兜铃酸给药3d后小鼠Scr水平明显升高（P〈0．01），组织学表现为严重肾小管损伤，至给药14d后出现明显肾小管问质纤维化改变。肾组织α-SMA、Vimentin和CollagenI在马兜铃酸给药7d后明显上调，第14天达峰值（P〈0．01）；E-Cadherin于给药后第14天出现明显下调并持续至第28天（P〈0．01）。实验组肾组织miR-21表达丰度于给药第7天后明显上调（P〈0．05），于第14天达到峰值（P〈0．01），并维持在较高水平。与anti-scramble＋AA组比较，anti-miR-21＋AA组小鼠Scr水平明显下降（P〈0．05）；肾小管间质病变减轻；肾组织α-SMA、Vimentin、CollageI和CollagenIV蛋白表达明显减少（均P〈0．05）；miR-21靶基因PTEN蛋白表达上调，其下游蛋白磷酸化蛋白激酶B／蛋白激酶B（p-AKT／AKT）比值下降（均P〈0．05）。结论大剂量马兜铃酸1次给药后即导致小鼠发生急性肾损伤，并诱导急性肾损伤后的肾小管间质纤维化病变。抑制肾脏miR-21表达可部分逆转肾小管间质纤维化，可能与上调PTEN／p-AKT信号通路相关。

英文摘要：

Objective To investigate the role of increased microRNA- 21 （miR-21） in the development of renal tubulointerstitial fibrosis secondary to aristolochic acid induced acute kidney injury. Methods C57BL/6J male mice were intraperitoneally injected with aristolochic acid at a dose of 10 mg/kg. Blood samples and kidneys were harvested at day 1, 3, 7, 14, 28 after aristolochic acid treatment. To assess the role of miR-21 in aristolochic acid induced acute kidney injury to chronic kidney disease progression, mice were intravenously injected with anti-miR-21 or anti-scramble （10 mg/kg） at 1 h before aristolochic acid dosing, as well as d5 and dl0 after aristolochic acid dosing. Results Increased serum creatinine and severe kidney injury were found at d3 after aristolochic acid treatment. Renal tubulointerstitial fibrosis was developed at d14 after aristolochic acid treatment. Protein expression of ot-SMA, vimentin and collagen I were significantly up-regulated at d7 and peaked at d14 （P 〈 0.01）, while protein abundance of E-Cadherin decreased at d14 and lasted until d28 （P 〈 0.01）. The abundance of miR-21 increased at d7 after aristolochic acid dosing, peaking at d14 and thereafter maintaining at a high level. Anti- miR- 21 intervention reheved renal injury with reduced serum creatinine （P 〈 0.05） and attenuation of renal tubulointerstitial fibrosis. Besides, the protein expression of α-SMA, vimentin, and collagen I/IV was all down-regulated after anti-miR-21 treatment （P 〈 0.05）. PTEN was up-regulated and the ratio of its downstream genes p-AKT/AKT was decreased. （P 〈 0.05） Conclusions A single high dose of aristolochic acid leads to acute kidney injury and the development of renal tubulointerstitial fibrosis secondary to AKI. Renal tubulointerstitial fibrosis could be partially reversed by inhibiting miR-21 via PTEN/p-AKT pathway.