Liu Bo, Hu Dong, Zhou Yu, Yu Yihang, Shen Lianju, Long Chunlan, Butnaru Denis, Timashev Peter, He Dawei, Lin Tao, Xu Tao, Zhang Deying, Wei Guanghui
Department of Urology, Children's Hospital of Chongqing Medical University Chongqing 400014, China.
Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders Chongqing 400014, China.
Am J Transl Res. 2020 Sep 15;12(9):4998-5014. eCollection 2020.
Mesenchymal stem cells (MSCs) and their conditioned medium attenuate renal fibrosis in an irreversible model of unilateral ureteral obstruction (UUO). However, the key components that play a role in the paracrine effects of MSCs and their mechanisms of action are not well understood. Therefore, in this study, we investigated whether exosomes released by human umbilical cord mesenchymal stem cells (hucMSC-Ex) would be able to attenuate renal fibrosis in an irreversible model of UUO and further explored potential mechanisms. In vivo, rats were divided into four groups: sham operation, sham operation transplanted with hucMSC-Ex, UUO, and UUO transplanted with hucMSC-Ex. hucMSC-Ex was administered via the left renal artery after total ligation of the left ureter. Rats were sacrificed after 14 days of obstruction. Renal function such as serum creatinine (Scr) or blood urea nitrogen (BUN) were monitored over the period. Histological changes, proliferation and apoptosis in tubular epithelial cells, and the levels of oxidative stress were measured. In vitro, NRK-52E cells were incubated with or without 5 ng/ml TGF-β1 and co-incubated with or without hucMSC-Ex for 48 h. Apoptosis and the levels of oxidative stress of NRK-52E cells were also measured. In the UUO group, the level of BUN and Scr, and the level of apoptosis and oxidative stress were all increased. In addition, the renal tubular injury and tubulointerstitial fibrosis were evident. However, all the above indices decreased significantly after treatment with hucMSC-Ex. , hucMSC-Ex significantly inhibited TGF-β1-induced apoptosis of NRK-52E cells by altering the production of ROS. Furthermore, it was observed that hucMSC-Ex inhibited apoptosis by inhibiting the activation of p38 mitogen-activated protein kinase (p38MAPK)/extracellular-signal-regulated kinase (ERK) 1/2 pathway. In conclusion, the results showed that hucMSC-Ex had positive effects towards UUO-induced renal fibrosis and apoptosis of renal tubular epithelial cells, and its mechanism of action was associated with inhibition of ROS-mediated p38MAPK/ERK signaling pathway. These data suggest the potential application of hucMSC-Ex in the treatment of chronic kidney disease, and also reveal the underlying mechanism of hucMSC-Ex action.
间充质干细胞（MSCs）及其条件培养基可减轻单侧输尿管梗阻（UUO）不可逆模型中的肾纤维化。然而，MSCs旁分泌作用中起作用的关键成分及其作用机制尚不清楚。因此，在本研究中，我们研究了人脐带间充质干细胞释放的外泌体（hucMSC-Ex）是否能够减轻UUO不可逆模型中的肾纤维化，并进一步探索其潜在机制。在体内，将大鼠分为四组：假手术组、假手术移植hucMSC-Ex组、UUO组和UUO移植hucMSC-Ex组。在左输尿管完全结扎后，通过左肾动脉给予hucMSC-Ex。梗阻14天后处死大鼠。在此期间监测肾功能，如血清肌酐（Scr）或血尿素氮（BUN）。检测组织学变化、肾小管上皮细胞的增殖和凋亡以及氧化应激水平。在体外，将NRK-52E细胞与5 ng/ml转化生长因子-β1（TGF-β1）一起或不一起孵育，并与hucMSC-Ex一起或不一起共孵育48小时。还检测了NRK-52E细胞的凋亡和氧化应激水平。在UUO组中，BUN和Scr水平、凋亡和氧化应激水平均升高。此外，肾小管损伤和肾小管间质纤维化明显。然而，用hucMSC-Ex治疗后，上述所有指标均显著下降。hucMSC-Ex通过改变活性氧（ROS）的产生，显著抑制TGF-β1诱导的NRK-52E细胞凋亡。此外，观察到hucMSC-Ex通过抑制p38丝裂原活化蛋白激酶（p38MAPK）/细胞外信号调节激酶（ERK）1/2通路的激活来抑制凋亡。总之，结果表明hucMSC-Ex对UUO诱导的肾纤维化和肾小管上皮细胞凋亡具有积极作用，其作用机制与抑制ROS介导的p38MAPK/ERK信号通路有关。这些数据表明hucMSC-Ex在慢性肾脏病治疗中的潜在应用，并揭示了hucMSC-Ex作用的潜在机制。
