Human umbilical cord mesenchymal stem cells-derived exosomes for treating traumatic pancreatitis in rats

Background: The therapeutic and protective efects of human umbilical cord mesenchymal stem cells-exosomes (hucMSC-Exs) on traumatic pancreatitis (TP) remain unknown. Here, we established a rat model of TP and evaluated and compared the therapeutic efects of hucMSC-Exs. Methods: HucMSC-Exs were obtained by ultracentrifugation and identifed using transmission electron microscopy and western blot analysis. TP rats were treated by tail vein injection of hUC-MSCs and hucMSC-Exs. Their homing in rats was observed by performing fuorescence microscopy. Rat pancreatic tissue was subjected to high-throughput sequence to determine transcriptome expression levels. The degree of pancreatic tissue damage was assessed by HE staining, the expression levels of amylase, lipase, and infammatory cytokines were detected by ELISA, apoptosis was detected by TUNEL assay, and the expression levels of various apoptosis-related proteins were detected by western-blot. The expression levels of apoptosis-related molecular markers were detected by RT-qPCR. Results: The colonization of exosomes was observed in pancreatic tissue. Compared to TP group, the histopathological score of pancreas was signifcantly decreased in the TP+hucMSC-Exs group (P<0.05). Compared to TP group, the activity of serum amylase and lipase was signifcantly decreased (P<0.05). The expression levels of IL-6 and TNF-α were signifcantly decreased, while those of IL-10 and TGF-β were signifcantly increased (P<0.05). The apoptosis index of the TP group was signifcantly increased (P<0.05), whereas that of the TP+hucMSC-Exs groups was signifcantly decreased (P<0.05). Compared to TP group, the expression levels of Bax, Bcl-2, and Caspase-3 were signifcantly decreased in the TP+hUC-MSCs group and TP+hucMSC-Exs group (P<0.05). Conclusion: HucMSC-Exs can colonize injured pancreatic tissue, inhibit the apoptosis of acinar cells, and control the systemic infammatory response to facilitate the repair of pancreatic tissue.背景：人脐带间充质干细胞外泌体（human umbilical cord mesenchymal stem cells-exosomes，hucMSC-Exs）对创伤性胰腺炎（traumatic pancreatitis，TP）的治疗与保护作用尚不明确。本研究构建了创伤性胰腺炎大鼠模型，并对hucMSC-Exs的治疗效果进行了评估与比较。方法：本研究通过超速离心法提取hucMSC-Exs，并采用透射电子显微镜与蛋白质印迹分析对其进行鉴定。将构建成功的TP模型大鼠分为两组，分别通过尾静脉注射人脐带间充质干细胞（human umbilical cord mesenchymal stem cells，hUC-MSCs）与hucMSC-Exs进行干预；通过荧光显微镜观察外泌体在大鼠体内的归巢情况。提取大鼠胰腺组织进行高通量测序，以明确其转录组表达水平。采用苏木精-伊红（HE）染色评估胰腺组织损伤程度，通过酶联免疫吸附实验（ELISA）检测淀粉酶、脂肪酶与炎症因子的表达水平，利用TUNEL染色法检测细胞凋亡情况，采用蛋白质印迹分析检测多种凋亡相关蛋白的表达水平，并通过实时定量聚合酶链式反应（RT-qPCR）检测凋亡相关分子标志物的表达水平。结果：在胰腺组织中可观察到外泌体的定植现象。与TP模型组相比，TP+hucMSC-Exs干预组的胰腺组织病理学评分显著降低（P<0.05）。与TP模型组相比，干预组血清淀粉酶与脂肪酶活性显著下降（P<0.05）；白细胞介素-6（IL-6）与肿瘤坏死因子-α（TNF-α）的表达水平显著降低，而白细胞介素-10（IL-10）与转化生长因子-β（TGF-β）的表达水平显著升高（P<0.05）。TP模型组的细胞凋亡指数显著升高（P<0.05），而TP+hucMSC-Exs干预组的凋亡指数则显著降低（P<0.05）。与TP模型组相比，TP+hUC-MSCs干预组与TP+hucMSC-Exs干预组中Bax、Bcl-2及半胱氨酸天冬氨酸蛋白酶-3（Caspase-3）的表达水平均显著降低（P<0.05）。结论：hucMSC-Exs可定植于受损的胰腺组织，抑制腺泡细胞凋亡，并通过调控全身炎症反应促进胰腺组织的修复。