红细胞生成素动员肾祖细胞以减缓保留肾单位手术大鼠的缺血再灌注损伤

Erythropoietin mobilizes renal progenitor cells to reduce ischemic reperfusion injury in rats with nephron- sparing surgery

目的观察红细胞生成素（EPO）对保留肾单位手术（NSS）大鼠肾脏缺血再灌注损伤的作用及机制。方法SD大鼠54只，切除右肾后，采用随机数表法分成以下3组：sham组：仅暴露左侧肾动脉，不做任何处理关腹；NSS组，术前磷酸盐缓冲液（PBS）腹腔注射，左侧肾动脉夹闭40min，同时切除左肾下极并用吸收性明胶海绵止血；EPO组，术前腹腔注射EPO，余同NSS组。术后12、24、72h收集血液及残余肾组织标本，检测各组血肌酐（Scr）、尿素氮（BUN）及进行肾小管病理损伤评分，流式细胞术检测肾祖细胞（RPC）比例，免疫组化检测CD133和增殖细胞核抗原（PCNA）的表达和分布，Western印迹法检测Wnt7b和B联蛋白（β-catenin）的蛋白表达。结果与Sham组比较，术后12、24、72hNSS组Scr、BUN、肾小管病理损伤评分均升高（均P〈0．05）；与NSS组比较，术后24hEPO组Scr和BUN降低，肾小管病理损伤评分也降低（均P〈0．05）。术后24h，NSS组RPC比例、CD133和PCNA蛋白表达、Wnt7b和β-catenin蛋白表达均高于Sham组（均P〈0．05）；与NSS组比较，EPO组RPC比例、CD133和PCNA蛋白表达、Wnt7b和β-catenin蛋白表达均升高（均P〈0．05）。结论EPO可减轻NSS缺血再灌注损伤，其机制可能与WntTb／β-catenin动员RPC修复肾小管上皮细胞损伤有关。

Objective To investigate the effects of the erythropoietin （EPO） on ischemia reperfusion injury （IRI） in rats with nephron-sparing surgery （NSS）. Methods Fifty-four Sprague Dawley rats were divided into 3 groups randomly after right kidney nephrectomy： Sham group, NSS group （PBS＋NSS） and EPO group （EPO＋NSS）. During NSS, renal artery was clamped for 40 min to induce IRI. Sham group just adopted exposure renal artery without vascular clamped. Rats in NSS group were injected intraperitoneally with PBS for 3 days before NSS. Rats in EPO group were injected intraperitoneally with EPO for 3 days before NSS. After 12 h, 24 h, 72 h, blood sample and renal tissues were collected. The serum creatinine （Scr） and urea nitrogen （BUN） were evaluated. The pathology injury was evaluated by HE staining. The CD24/CD133 double- positived renal progenitor cells （RPCs） were tested by flow cytometry. The CD133 and PCNA protein were quantified by immunohistochemical staining. The expressions of Wnt7b and β- catenin protein were detected by Western blotting. Results Rats in NSS group had more elevated Scr, BUN and pathology injury scores 12 h, 24 h and 72 h after operation than those in Sham group （all P 〈 0.05）. Compared with those in the NSS group, the Scr and BUN in the EPO group were significantly lower 24 h after the surgery （all P 〈 0.05）, and the pathology injury score also decreased （P 〈 0.05）. The proportion of RPCs, expressions of CD133 and PCNA, and expressions of Wnt7b and β- catenin protein were significantly higher after 24 h of the surgery in NSS group than those in the Sham group （all P 〈 0.05）. While compared with those in the NSS group, the proportion of RPCs and expressions of CD133, PCNA, Wnt7b and β- catenin increased at the EPO group （all P 〈 0.05）. Conclusions EPO can reduce the IRI after NSS, and its mechanism may be related to the mobilization of the RPCs by the Wnt7b/β-catenin signal pathway.