中文摘要：

目的：观察体外缺氧损伤的大鼠肾小管上皮细胞（NRK-52E）凋亡情况以及分离纯化人脐带间质干细胞来源的外切体（hucMSCs-exosomes）对其干预作用。方法：将体外培养的NRK-52E细胞随机分为对照组、缺氧损伤模型组和hucMSCs-exosomes（0.5,1.0 mg/ml）预处理组。随后进行细胞计数,蛋白质印迹法检测凋亡相关蛋白（Bcl-2,bax）的表达变化,流式细胞仪检测细胞周期以及凋亡率的变化。结果：与对照组相比,模型组细胞凋亡相关指标均明显升高,细胞计数下降（P〈0.01）,Bcl-2/bax表达下调（P〈0.01）,细胞周期S期阻滞以及凋亡细胞比例明显增多。而hucMSCs-exosomes预处理组可明显改善缺氧损伤时的细胞活力,上调Bcl-2/bax的表达,改善细胞周期和凋亡细胞的比例（P均〈0.05）。结论：NRK-52E在缺氧损伤时有明显的细胞凋亡,而hucMSCs-exosomes预处理可能通过抗凋亡途径减轻缺氧时细胞的损伤。本实验可为进一步研究hucMSCs-exosomes在组织损伤修复中的生物学功能和相关机制提供实验基础。

英文摘要：

Objective： To observe the apoptosis of injured rat renal tubular epithelia cells（NRK-52E） induced by cell hypoxia in vitro and the biological functions of hucMSCs-derived exosomes（hucMSCs-exosomes）.Methods： Cultured NRK-52E were divided into control group,model group and hucMSCs-exosomes（0.5,1.0mg/ml） pretreated groups.In vitro,NRK-52E were exposed to hypoxia for 8 hours.Then we counted the cells and detected the expression of Bcl-2,bax by Western Blotting.The cell cycles and apoptosis were measured by flow cytometry.Results： Compared with control group,the model group showed lower cell counts（P〈0.01） and higher apoptosis ratio.We also observed that the expression of Bcl-2/bax was decreased（P〈0.01） and the cell cycle was blocked at S phase.Compared with model group,hucMSCs-exosomes（0.5,1.0 mg/ml） pretreated groups showed apparent tolerance to hypoxia injury in vitro,which manifestated a higher cell vability,lower apoptosis ratio,increased expression of Bcl-2/bax and relieve the block of S phase（all P〈0.05）.Conclusion： Hypoxia could cause the apoptosis of cells in vitro.hucMSCs-exosomes exhibited anti apoptosis ability in vitro.All these may provide experimental evidences for the mechanisms of hucMSCs-exosomes in therapy of tissue injury.