骨髓基质细胞体外分化移植对局灶脑缺血大鼠分子表达及行为的影响

Intravenous administration of rat bone marrow derived endothelia cells in rats after stroke

目的观察大鼠骨髓基质细胞分化为内皮细胞后静脉移植治疗大鼠永久大脑中动脉闭塞模型(MCAO)后缺血脑血管内皮细胞生长因子(VEGF)及其受体FLK-1的表达以及动物行为学改变。方法利用400 ng/ml重组人粒细胞巨噬细胞集落刺激因子(rhGM-CSF)在体外诱导骨髓基质细胞分化为内皮细胞。线栓法制作永久SD大鼠MCAO模型(n=45),24 h后细胞移植组(n=15)舌静脉注射3×106分化后的内皮细胞,对照组1(n=15)注射等量PBS,对照组2(n=15)血管闭塞后不予任何处理。在细胞移植前及移植后1、3、5、7、14 d分别采用姿势反射实验、肢体不对称应用实验和角落实验观察大鼠动物行为学评分的变化,并通过免疫组化染色方法观察缺血脑组织血管内皮细胞生长因子(VEGF)及其受体FLK-1的表达。结果细胞移植组动物行为学评分优于对照组1、2,在移植后第7天和第14天较两个对照组有显著性差异(P<0.05);各组缺血侧脑组织缺血周边和皮层VEGF、FLK-1阳性细胞较非缺血侧增多(P<0.05),其中以细胞移植组最明显(P<0.05);VEGF主要表达在神经元、神经胶质细胞和部分内皮细胞,FLK-1主要表达在内皮细胞和部分神经元、神经胶质细胞;细胞移植组缺血侧毛细血管增生较对照组多(P<0.05)。结论骨髓基质细胞体外诱导分化后的内皮细胞静脉移植可以改善大鼠局灶脑缺血的神经功能;内皮细胞移植后可促进缺血脑组织VEGF、FLK-1的表达;动物神经功能的改善机制可能与VEGF、FLK-1的表达增加,内皮细胞及毛细血管增殖有关。

Objective To observe the therapeutic benefit of administration of endothelial cells derived from rat bone marrow cells in ischernic stroke rats and to explore the related mechanism. Methods Prepared endothelial cells from bone marrow stromal cells （BMSC） of rats, which were multiplied and differentiated in the medium with 400ng/ml rhGM-CSF in vivo. Rats were subjected to permanent cerebral middle artery occlusion （MCAO） models（n=45）. Injected intravenously via tongue vein with 3 × 10^6 endothelial cells 24 h after stroke for test groups（n= 15） ; injected same amount PBS for control group 1 （n=15） ; control groups without any intervention after stroke （n=15）. Neurologic functional behaviour tests （postural reflex test, limb use asymmetrical test and corner test） were performed before transplantation and 1,3,5,7,14 d after stroke. Meanwhile, immunohistocbemistry staining was used to identify for vascular endothelial growth factor （VEGF） and its receptor FLK-1 expression in ischemic brain tissue. Results Significant recovery of neurological function was detected in rats treated with endothelial cells on the 7th day and 14th day after stroke, com- pared with control group 1 and group 2（P〈0.05） ;The number of positive cells of VEGF, FLK-1 were significant more in the periischemic tissue and ipsilateral cortex, compared with non-ischemic hemisphere. The maximum number of positive cells was in the test group which was treated with endothelial cells（P〈0.05）;VEGF was mainly expressed at neurons, glial cells and part of endothelial cells ; FLK-1 was mainly expressed at endothelial cells and part of neurons and glial cells ; capillary hyperplasia was demonstrated more at the ischemic hemisphere in the rats treated with endothelial cells, compared with control group 1 or 2. Conclusion Endothelial cells derived from bone marrow cells in rats could improve neurological outcome in rats with ischemic stroke. The effect starts to be significant on the 7th day after transplantation and it shows more significant effect on the 14th day. Endothelial cells transplantation will enhance VEGF, FLK-1 expression at ischemic area and increases capillary hyperplasia formation, which may relate to the potential mechanism of neurological outcome improvement post stroke in rats.