骨髓间充质干细胞移植对缺血再灌注大鼠脑神经细胞凋亡及Bcl-2、Bax蛋白表达的影响

Effects of mesenchymal stem cell transplantation on neural cell apoptosis and expressions of Bcl-2,Bax in rat cerebral ischemia-reperfusion tissue

目的:探讨骨髓间充质干细胞(MSCs)移植对缺血再灌注大鼠脑组织神经细胞凋亡及Bcl-2、Bax蛋白表达的影响。方法:SD大鼠84只,随机分为假手术组(n=12)、模型组(n=24)、磷酸盐缓冲液(PBS)组(n=24)和MSCs组(n=24)。模型组、PBS组和MSCs组采用线栓法建立大鼠大脑中动脉缺血模型,假手术组除不插尼龙线外,其余步骤相同。PBS组和MSCs组分别于建模成功后24h分别经颈动脉注入等体积的PBS液和已制备好的同种异体MSCs悬液。每组于脑缺血2h再灌注2d、4d、6d、8d时行神经功能缺损评分及脑灌注固定取材,采用免疫组化染色及TUNEL检测脑组织Bcl-2、Bax蛋白的表达及凋亡细胞数。结果:假手术组在各时间点神经功能评分为0分,无神经功能缺损,未见细胞凋亡,未见Bcl-2和Bax表达。与模型组和PBS组比较,脑缺血2h再灌注4d开始,MSCs组神经细胞凋亡数、Bax蛋白表达和神经功能缺损评分较低,Bcl-2蛋白表达较高,差异有统计学意义(P<0.05)。结论:骨髓间充质干细胞移植能改善脑损伤大鼠的功能;上调Bcl-2蛋白表达,下调Bax蛋白表达,减少神经细胞凋亡,可能是其主要机制之一。

Aim： To investigave the effects of mesenchymal stem cells （MSCs） transplantation on the apoptosis of neural cells and the expressions of Bcl-2 ,Bax in rat cerebral ischemia-reperfusion tissue. Methods：MSCs were isolated from the bone marrow of SD rat and cultured in vitro. A total of 84 healthy adult male SD rats were randomly divided into sham operation group （ n = 12 ） , model group （ n = 24） , PBS group （ n = 24） and MSCs treatment group （ n = 24） , and rats of the last three groups were established cerebral ischemia-reperfusion model with suture emboli method. At 2 d, 4 d, 6 d, 8 d after reperfusion,the neurological deficits of rats in every group were evaluated,and brain tissue was obtained to detect the cell apoptosis by TUNEL method, and Bcl-2,Bax proteins, using immunohistochemical staining. Results： The neural cell apoptosis, the expressions of Bax and Bcl-2 of sham operation group were negative, Compared with those of the model group and PBS group, the neurological scores of MSCs treatment group significantly decreased, the number of apoptotic neural cells and the expression of Bax were lower,while the expression of Bcl-2 significantly increased （P 〈 0.05 ）. Conclusion： MSCs treatment could improve the neurological function of brain injury rat, which may be related to up-regulating Bcl-2 and down-regulating Bax, and reducing apoptosis of neural cells.