基质细胞衍生因子-1α/趋化因子CXC受体4诱导内皮祖细胞血管新生促进脑卒中的神经康复机制

SDF-1α/CXCR4 induces endothelial progenitor cell angiogenesis to promote neural rehabilitation following stroke

目的探讨基质细胞衍生因子-1α/趋化因子CXC受体4(SDF-1α/CXCR4)诱导内皮祖细胞(EPCs)血管新生在脑卒中神经康复中的作用。方法采用流式细胞仪和ELISA法分析EPCs对氧糖剥夺(OGD)诱导人脑微血管内皮细胞(HBMECs)凋亡、SDF-1α水平的影响。大鼠建立大脑中动脉闭塞(MCAO)模型,分别采用EPCs、缺氧内皮细胞条件培养液预处理EPCs(HBMECs-pEPCs)或AMD3100(CXCR4拮抗剂)进行治疗。在第6周时通过Morris水迷宫试验评估大鼠认知功能,和第7周时采用免疫荧光染色观察大脑皮层血管生成情况。结果EPCs处理降低OGD诱导的HBMECs凋亡率(P<0.05),并增加血管环数(P<0.05)。OGD-HBMECs诱导EPCs中SDF-1α表达增加(P<0.05)。CXCR4基因敲除减轻了EPCs对OGD-HBMECs的抗凋亡作用(P<0.05)。MCAO大鼠在建模后第4天时大脑皮层中EPCs、Claudin5阳性血管数量和SDF-1α蛋白水平明显增加(P<0.05)。与EPCs治疗相比,HBMECs-pEPCs治疗能显著增加大鼠MCAO模型的血管密度(P<0.05),并改善学习记忆障碍,而AMD3100逆转了HBMECs-pEPCs的治疗作用。结论HBMECs-pEPCs通过SDF-1α/CXCR4轴有效地促进大鼠MCAO模型神经血管重塑和认知功能恢复。

Objective To investigate the role of vascular endothelial progenitor cells(EPCs)angiogenesis induced by SDF-1α/CXCR4 in neurological rehabilitation after stroke.Methods Flow cytometry and ELISA were used to analyze the effects of EPCs on oxygen-glucose deprivation(OGD)-induced apoptosis and SDF-1αlevels in human brain microvascular endothelial cells(HBMECs).A rat model of MCAO was established.EPCs were pretreat-ed with EPCs,HBMECs-pEPCs or AMD3100(CXCR4 antagonist),respectively.Cognitive function was assessed by Morris water maze test at week 6,and angiogenesis in cerebral cortex was observed by immunofluorescence staining at week 7.Results EPCs treatment decreased the apoptotic rate of HBMECs induced by OGD(P<0.05)and increased the number of vascular ring(P<0.05).OGD-HBMECs induced an increase in SDF-1αexpression in EPCs,and CXCR4 knockdown alleviated the anti-apoptosis effect of EPCs on OGD-HBMECs(P<0.05).The number of EPCs and vessels with positive Claudin5 and level of SDF-1αprotein in cerebral cortex of MCAO rats markedly increased on day 4 after the model establishment(P<0.05).As compared with EPCs treatment,HBMECs-pEPCs treatment significantly increased vascular density(P<0.05)and improved deficits of learning and memory in the rat model of MCAO,while AMD3100 reversed the therapeutic effect of HBMECs-pEPCs.Conclusions HBMECs-pEPCs can effectively promote neurovascular remodeling and cognitive function recovery via SDF-1α-CXCR4 axis in the rat model of MCAO.