胎盘间充质干细胞外泌体对大鼠全脑缺血再灌注保护作用及机制的研究

A study on the protective effect of exosomes derived from placental mesenchymal stem cells on global cerebral ischemia-reperfusion and its mechanism in rats

目的明确胎盘间充质干细胞来源外泌体对大鼠全脑缺血再灌注的保护作用效应并探索可能的机制。方法在胎盘间充质干细胞中分离获得外泌体。采用改良Pulsinelli四血管闭塞法在Wistar大鼠中建立全脑缺血再灌注模型。将大鼠随机分为3组,分别为假手术组、模型组及外泌体治疗组,于给药治疗后,在24、48和72 h时间点测量脑组织含水量和Evans blue染色量,并采用Western-blotting确定脑组织中Caveolin-1和ZO-1的水平。结果本研究成功分离胎盘间充质干细胞,并分离获得了其来源的外泌体,该外泌体能够被磷钨酸染色,尺度分布为50~200 nm,且表达CD63c不表达GM-130a。在48和72 h时,治疗组脑组织水含量相较于模型组有显著下降,且治疗组与假手术组相比在72 h无显著差异。EB染色的结果与水含量的结果相似,但是在72 h仍高于假手术组。Western-blotting和免疫组化显示外泌体能够升高Caveolin-1和ZO-1的水平。结论胎盘来源外泌体能够通过调节Caveolin-1和ZO-1的水平改善全脑缺血再灌注的严重程度,可能是在老年患者中治疗缺血再灌注一种潜在方案。

Objective To clarify the protective effect of exosomes derived from placental mesenchymal stem cells on global cerebral ischemia-reperfusion in rats and explore its possible mechanism.Methods Exosomes were isolated from placental mesenchymal stem cells.A global brain ischemia-reperfusion model was established in Wistar rats with modified Pulsinelli four-vessel occlusion method.The rats were randomly divided into 3 groups:sham operation group,model group and exosome treatment group.After medication treatment,the water content and Evans blue staining content of the brain tissue were measured at 24,48,and 72 hour time points,and Western blotting was used to determine the levels of Caveolin-1 and ZO-1 in brain tissue.Results Placental mesenchymal stem cells were successfully isolated and exosomes derived from them were obtained.The exosomes could be stained by phosphotungstic acid,with a size distribution of 50-200 nm,and it could express CD63c,but not GM-130a.At 48 and 72 hours,the water content in the brain tissue of the treatment group was significantly lower than that of the model group,while there was no significant difference between the treatment group and the sham group at 72 h.The results of EB staining were similar to those of water content,but were still higher than those of the sham group at 72 h.Western-blotting and immunohistochemical tests showed that exosomes could increase the levels of Caveolin-1 and ZO-1.Conclusion Placenta-derived exosomes can relieve the severity of global cerebral ischemia-reperfusion by regulating the levels of Caveolin-1 and ZO-1,which may be a potential method for the treatment of ischemia-reperfusion in elderly patients.