骨髓基质细胞治疗脑缺血过程中血管内皮生长因子对其趋化性作用的实验研究

目的:探讨骨髓基质细胞(BMSCs)枕大池注射治疗大鼠大脑中动脉闭塞(MCAO)过程中血管内皮生长因子(VEGF)对其趋化性作用。方法:从2月龄大鼠的后肢骨骨髓中取原代BMSCs,经体外扩增培养、鉴定,5-溴脱氧尿苷(BrdU)体外标记细胞。线栓法制作大鼠MCAO模型24 h后,造模成功大鼠随机分为对照组(n=10),枕大池注射生理盐水;BMSCs治疗组(n=10),枕大池注射BMSCs(1×106个);BMSCs+VEGF治疗组(n=10),枕大池注射BMSCs(1×106个)后48 h、72 h、96 h,分3次枕大池注射VEGF 20 ng。各组分别在治疗1周和4周时各处死5只大鼠,HE染色和BrdU免疫组织化学染色。结果:各组大鼠HE染色后均能在左侧大脑半球发现梗死灶。对照组各时间点未见明显BrdU阳性细胞;2个治疗组在治疗1周时梗死灶周围的BrdU阳性细胞数目均显著多于4周时(P0.01);治疗1周和4周时,BMSCs+VEGF治疗组梗死灶周围的BrdU阳性细胞数目均显著多于BMSCs治疗组(P0.01)。结论:BMSCs枕大池注射治疗大鼠MCAO时,移植细胞向缺血部位迁移,加用外源性VEGF对BMSCs向梗死灶周围迁移有趋化性作用。

A Study of the Chemotaxic Effect of Vascular Endothelial Growth Factor on Bone Marrow Stromal Cells in Treatment of Rats with Cerebral Ischemia

Objective: To explore the chemotaxic effect of vascular endothelial growth factor(VEGF) on bone marrow stromal cells(BMSCs) in treating rats with middle cerebral artery occlusion(MCAO).Methods: Primary BMSCs,which were obtained from the bone marrow in the hindlimbs of two-month-old rats,were amplified,identified and marked by BrdU in vitro.The acute middle cerebral artery occlusion(MCAO) model of rats was established using Longa modified method.Twenty-four hours later,rats with middle cerebral artery occlusion were randomly divided into three groups.The rats in control group(n=10) were treated with normal saline and the ones in BMSCs treatment group(n=10) were treated with BMSCs,which were introduced into the cisterna magna.The ones in BMSCs+VEGF treatment group(n=10) were treated with both BMSCs and VEGF in the same way.The brain tissues were obtained at one week or four weeks after the treatment and HE staining and BrdU immunohistochemical staining techniques were used to the brain sections.Results: No BrdU positive cells were observed in the control group.In contrast,there were a considerable BrdU positive cells around the infarction areas at one week which were detected in both the experimental groups.At week 1 and 4,BrdU positive cells around the infarction areas in rats of BMSCs+VEGF treatment group were significantly more numerous than that in the BMSCs treatment group.Conclusion: BMSCs could migrate towards ischemic areas when administered into the cisterna magna and exogenous VEGF might be of chemotaxic effect on the migration of BMSCs.