脐带间充质干细胞外泌体对大鼠肾间质纤维化的抑制作用

目的: 探讨人脐带间充质干细胞来源的外泌体（human umbilical cord mesenchymal stem cell derived exosomes，hucMSC-Ex）对单侧输尿管梗阻（unilateral ureteral obstruction, UUO）所致大鼠肾小管间质纤维化的修复作用。方法: 分离培养hucMSC并从培养上清液中提取hucMSC-Ex。采用单侧输尿管结扎法构建肾间质纤维化模型，将大鼠随机分为假手术组、UUO组和hucMSC-Ex组，每组6只，hucMSC-Ex组大鼠在术后24 h 尾静脉注射250 μg hucMSC-Ex。7 d后收集肾脏组织，观察各组肾脏大体观。蛋白质印迹检测肾组织纤维化相关蛋白TGF-β1、E-钙黏蛋白和波形蛋白，并对肾脏组织切片进行HE染色、Masson染色和免疫组织化学染色，观察大鼠梗阻侧肾脏病理结构变化、炎症细胞浸润情况及肾纤维化程度，综合评价hucMSC-Ex对大鼠肾脏纤维化的抑制效果。结果： 与假手术组相比，UUO组大鼠肾脏炎性细胞浸润显著增加，组织结构严重破坏，广泛胶原沉积；hucMSC-Ex干预后组织形态结构部分恢复，胶原沉积减少，炎性细胞浸润减少。同时，UUO组大鼠肾脏α-平滑肌肌动蛋白（α-SMA）、TGF-β1和波形蛋白表达升高，E-钙黏蛋白表达降低；但hucMSC-Ex输注后能够抑制α-SMA和TGF-β1的表达，逆转上皮间质转化。结论： hucMSC-Ex可以减轻大鼠肾组织病理损伤，延缓大鼠肾间质纤维化的进程。

The inhibition of umbilical cord mesenchymal stem cell-derived exosomes on rat renal interstitial fibrosis

Objective: To investigate the repair effect of human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Ex) on renal tubular interstitial fibrosis induced by unilateral ureteral obstruction (UUO) in rats. Methods: Human umbilical cord-derived mesenchymal stem cells were isolated and cultured, and hucMSC-Ex was extracted from the culture supernatant by ultrafiltration and gradient centrifugation. A unilateral ureteral ligation method was used to construct a renal interstitial fibrosis model. All rats were randomly divided into sham operation group， UUO group and hucMSC-Ex treatment group. Two hundred-fifty μg hucMSC-Ex was injected into the tail vein after the operation of treatment group rats. Seven days later, kidney tissues were collected and the general appearance of the kidneys in each group was observed. Western blotting was used to detect the expression of protein related to renal fibrosis: TGF-β1, E-cadherin and Vimentin. The kidney tissue sections were stained with HE staining, Masson staining and immunohistochemical staining to measure rat renal pathological changes, inflammatory cell infiltration and the degree of renal fibrosis in the obstructed rats. Results: The inflammatory cell infiltration in the kidney of UUO group significantly increased, the tissue structure was severely damaged, and extensive collagen deposition was observed. After hucMSC-Ex treatment, the tissue morphology and structure of were partially recovered, collagen deposition and inflammatory cell infiltration were reduced. At the same time, the expression of α-SMA, TGF-β1 and Vimentin in the kidney of UUO group increased, while the expression of E-cadherin decreased. However, hucMSC-Ex treatment could inhibit the expression of α-SMA and TGF-β1 and reverse the epithelial-mesenchymal conversion. Conclusion: hucMSC-Ex can reduce the pathological damage of renal tissue in rats and delay the progress of renal interstitial fibrosis in rats.