骨髓基质细胞移植对局灶性脑缺血大鼠内源性神经前体细胞增殖的动态影响

Effects of bone marrow stromal cell transplantation on the proliferation of endogenous neural precursor cells in rats after focal cerebral ischemia and reperfusion

目的探讨骨髓基质细胞(bone marrow stromal cells,BMSCs)移植对局灶性脑缺血大鼠内源性神经前体细胞增殖的动态影响。方法建立大鼠大脑中动脉缺血再灌注模型。24只健康SD大鼠分为假手术组、缺血对照组、缺血移植组。大鼠局灶性脑缺血再灌流24 h后各组腹腔注射5-溴脱氧尿核苷(bromodeoxyuridine,BrdU)标记处于增殖状态的神经前体细胞,最后一次注射后2 h处死。通过神经缺损评分观察移植后神经功能改善情况。应用免疫组织化学染色及原位细胞凋亡检测脑组织BrdU阳性及凋亡细胞。结果脑梗死后侧脑室室管膜下区、海马齿状回区及梗死灶边缘BrdU阳性细胞迅速增多(P<0.05)。移植BMSCs后BrdU阳性细胞明显多于对照组(P<0.05),随移植时间的延长,增加更趋明显。同时,BMSCs移植后大鼠神经功能得到明显康复,缺血边缘区凋亡细胞明显减少伴梗死体积缩小。结论BMSCs可促进局灶性脑缺血大鼠内源性神经前体细胞的增殖、迁移,对脑缺血再灌注损伤起保护作用。

Objective To study the effects of bone marrow stromal cells（BMSCs） on the proliferation of endogenous neural precursor cells in rats after focal cerebral ischemia and reperfusion. Methods The model of middie cerebral artery occlusion（MCAO） and reperfusion was set up. Twenty-four Sprague-Dawley rats were divided into sham-operated group, ischemia control group and BMSCs transplanted group. BrdU that labeled the proliferating neural precursor cells were injected intraperitoneally in rats after focal cerebral ischemia and reperfusion for 24 hours. The rats were sacrificed 2 hours after the last injection. Neurological Severity Score（NSS） was evaluated after transplantation. The brain sections were used for BrdU immunohistochemical staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling（TUNEL） staining. Results The number of BrdU-positive cells in the subventricular zone, hippocampus and the edge of ischemia quickly increased after focal cerebral ischemia and reperfusion（ P 〈 0.05）. The number of BrdU-positive ceils in the BMSCs transplantation group increased compared with that in the ischemia control group （ P 〈 0.05）. Furthermore, the BrdU-positive cells increased as time went on. At the same time, the recovery of neurological function in BMSCs transplantation group was evident, the infarct volumes and the number of apoptotic cells decreased significantly. Conclusion BMSCs promotes the proliferation and immigration of endogenous neural precursor ceils that may offer neuroprotection against cerebral ischemia and reperfusion.