骨髓基质细胞移植治疗大鼠实验性脑梗死的疗效分析及组织病理学观察

Intracerebral transplantation of bone marrow stromal cells in rats with cerebral ischemia： effects on neurofunctional recovery and histological investigation

目的观察大脑中动脉闭塞（MCAO）模型大鼠脑内移植骨髓基质细胞（BMSCs）的治疗作用，分析植入梗死灶不同区域的BMSCs的存活、迁移情况以及植入细胞的行为与脑内微环境中GFAP阳性细胞的形态关系。方法75只成年SD大鼠采用随机数字表法分为MCAO组（n=50）和BMSCs移植组（n=25），所有动物均采用线栓法制作MCAO 1h模型，24h后BMSCs移植组脑内注射BrdU标记的同种异体BMSCs（2×10^6个），MCAO组注射等量PBS。MCAO前及MCAO后第1（移植前）、3、5、7、10、14天应用加速转轮试验和贴纸去除试验检测神经功能缺损情况；第14天处死动物，取脑组织切片应用HE染色观察两组的缺血病灶范围，行BrdU和GFAP免疫组化染色观察BMSCs在不同区域和不同胶质细胞环境下的存活和迁移情况。结果BMSCs移植组MCAO后7d加速转轮试验结果优于MCAO组，差异有统计学意义（P〈0．05）；组织学观察发现植入缺血半暗带区的细胞存活数量最多，且向病变方向放射状迁移，植入缺血病灶核心的细胞甚少存活，且无迁移现象。结论BMSCs脑内移植可改善MCAO后大鼠神经运动功能：活化的星形胶质细胞构成适合植入细胞存活、迁移的环境，而胶质瘢痕阻碍了细胞的迁移。

Objective To observe the therapeutic effect ofintracerebral transplantation of bone marrow stromal cells （BMSCs） on neurofunctional recovery after cerebral infarction in rats, and investigate the survival and migration of the transplanted BMSCs in different areas of the ischemic lesion. Methods Seventy-five adult SD rats were randomly divided into MCAO group （n=50） and BMSCs transplantation group （n=25）. All the rats were subjected to middle cerebral artery occlusion （MCAO） by intraluminal filament placement for 1 h, and 24 h after MCAO, the rats in BMSCs transplantation group received injection of 2×10^6 rat BMSCs into the ischemia hemisphere. Rotarod and modified adhesive removal tests were performed before and at 1, 3, 5, 7, 10 and 14 days after MCAO. The rats were sacrificed after the last test to measure the sizes of the ischemie lesions and observe the survival and migration of the transplanted BMSCs using BrdU staining and immunohistochemical staining for glial fibrillary acidic protein （GFAP）. Results In the rotarod test, significant neurological function recovery was observed in rats receiving BMSC transplantation 7 days after MCAO in comparison with the rats without the transplantation （P〈0.05）. No obvious difference in the lesion sizes was found at 14 days after MCAO between the two groups. In rats receiving BMSCs transplantation, survival and migration of the transplanted BMSCs were identified in different areas of the ischemic lesion. BMSCs injected to the penumbra were found to survive better and preferentially migrate toward the lesion core. Only few BMSCs injected to the lesion core survived and no cell migration was detected. Large amount of BrdU-positive cells were detected in the areas where activated GFAP-positive cells were present. The migration of the BMSCs, however, appeared to be limited by the glial scar. Conclusions Intracerebral transplantation of BSMCs can promote the motor function recovery of the rats after cerebral ischemia. The activated astrocytes provide appropriate environment for the survival of the transplanted BMSCs and allow their migration to the ischemic core, while the glial scar forms an obstacle to the migration of the BMSCs.