骨髓间充质干细胞移植治疗脑缺血大鼠时间窗的研究

Therapeutic time window of bone marrow mesenchymal stem cells for treatment of rats with cerebral ischemia

目的探讨骨髓间充质干细胞(MSCs)移植治疗脑缺血模型大鼠的时间窗及最佳移植时间点。方法雄性SD大鼠56只,随机分为移植组32只和对照组24只,在建立大鼠大脑中动脉缺血2 h再灌注模型后分为1、7、14、21 d 4个时间点。对大鼠进行改良神经功能缺损评分、HE染色、Bielshowsky Iuxol Fast Blue染色、直接免疫荧光染色和免疫组织化学染色。结果移植组1、7 d在移植14 d后,14、21 d在移植21 d后改良神经功能缺损评分明显低于对照组(P<0.05)。移植组1、7 d胶质纤维酸性蛋白阳性细胞数、突触素累计吸光度值、胼胝体面积明显高于对照组(P<0.05)。移植组1、7、14、21 d Ki-67阳性细胞数明显高于对照组(P<0.05)。移植组7 d神经元特异性烯醇酶累计吸光度值明显高于对照组(P<0.05)。移植组1、7 d Nogo A阳性细胞数明显低于对照组(P<0.05)。结论 MSCs移植治疗大鼠脑缺血模型的时间窗可延长至制模后的21 d,最佳移植时间点为制模后7 d。MSCs移植治疗脑梗死的作用机制可能与其促进内源性修复相关。

Objective To investigate the therapeutic time window and the best time of bone marrow mesenchymal stem cells（MSCs） transplantation for treatment of cerebral ischemia. Methods Fifty-six male Sprague-Dawley rats were randomly divided into the transplantation group （n = 32） and control group （n = 24） ,and MSCs or PBS were transplanted 1 d,7 d,14 d,21 d after 2-hour MCAO. Functional tests（mNSS）, HE and Bielshowsky-Luxol Fast Blue staining, direct immuno- fluorescence and immunohistochemical staining of brain were performed. Results In 1 d and 7 d transplantation groups,on 14th d after transplantation, in 14 d and 21 d transplantation groups, on 21st d after transplantation, mNSS scores were significantly lower than that in controlgroup. In 1 d and 7 d transplantation groups, GFAP^＋ cell numbers, synaptophysin IOD and corpus callosum area were significantly higher than those in control group. In 1 d,7 d, 14 d and 21 d transplantation groups,Ki-67^＋ cell numbers were significantly higher than that in control group （P〈 0.05）. In 7 d transplantation group,NSE expression was significantly higher than that in control group （P 〈 0.05）. In 1 d and 7 d transplantation groups,Nogo-A^＋ cell numbers were significantly lower than that in control group （P〈 0.05）. Conclusion The time window of MSCs transplantation for treatment of cerebral ischemia can be extended up to 21 d after MCAO and the best time for transplantation is 7 d after MCAO. Mechanisms of MSCs therapy of ischemic injured brain may lie in enhancing the endogenous restoration.