中文摘要：

目的：探讨人脐带血间充质干细胞（mesenchymal stem cells，MSC）移植对脑梗死大鼠外周血Foxp3调节性T细胞改善缺血性脑损害的可能机制。方法选择SD大鼠40只，随机分为假手术组、对照组、生理盐水组、MSC组，每组10只。各组大鼠分别测定1 d、7 d、14 d、28 d外周血单个核细胞中Foxp3 mRNA表达和神经功能缺损评分；TUNEL法检测神经细胞凋亡数。结果 MSC组14 d、28 d神经功能缺损评分明显低于对照组及生理盐水组[（6．1±1．4）分vs （7．3±1．1）分，（7．3±0．9）分；（5．2±1．0）分vs （6．2±1．0）分，（6．3±0．5）分；P＜0．05]；28 d凋亡细胞数明显少于对照组及生理盐水组（P＜0．05）。对照组、生理盐水组及MSC组1 d、7 d、14 d、28 d外周血Foxp3 mRNA表达明显高于假手术组，差异有统计学意义（P＜0．01）。MSC组1 d、7 d外周血Foxp3 mRNA表达明显高于对照组和生理盐水组，差异有统计学意义（P＜0．05）。结论 MSC移植改善大鼠急性脑缺血神经功能恢复的机制之一，可能与上调免疫炎性反应初期Foxp3 mRNA表达有关。

英文摘要：

Objective To explore the possible mechanisms of human umbilical cord blood mesenchymal stem cells（hUCB-MSCs） transplantation on improving ischemic brain damage ,Foxp3 expression in peripheral blood was observed inrats following focal cerebral ischemia reperfusion （I/R）.Methods 40 healthy SD rats were randomly divided into shamoperation group,I/R group,saline group and hUCB-MSCs group.Foxp3 mRNA expression in peripheral blood mononuclearcells and modified neurological severity score （mNSS） were measured 1 d,7 d,14 d and 28 d after reperfusion.Neural cellapoptosis was detected by TUNEL 4 w after reperfusion.Results mNSS in hUCB-MSCs group 14 d and 28 d after reperfusionwas significantly lower than that of control group and saline group [（6.1 ±1.4） points vs （7.3 ±1.1） points,（7.3 ±0.9） points;（5.2 ±1.0） points vs （6.2 ±1.0） points,（6.3 ±0.5） points;P 〈0.05].The number of neural cell apoptosisin hUCB-MSCs was obviously less than that of control group and saline group 28 d after reperfusion （P 〈0.05）.Foxp3mRNA expression level in hUCB-MSCs group was significantly higher than that of control group and saline group 1 d and7 d after reperfusion （P 〈0.05）.Conclusion Up-regulation of Foxp3 mRNA expression is one of the possible mechanismsof hUCB-MSCs transplantation on improving ischemic brain damage the mechanisms of inhibiting inflammatory reac -tion.