探讨脑缺血大鼠骨髓基质细胞移植后减少神经细胞凋亡的作用

Effects of bone marrow stromal cells derived neural stem cells on the changes of apoptosis and correlative proteins in rats after focal cerebral ischemia and reperfusion

目的探讨大鼠局灶性脑缺血后骨髓基质细胞移植对神经细胞凋亡及相关蛋白表达的影响。方法取大鼠股骨髓基质细胞,分化培养为骨髓基质细胞源神经干细胞。将32只健康SD大鼠随机平均分为4组。A组不建立局灶性脑缺血模型,不做任何移植,其余步骤同其他组。B、C、D组均建立局灶性脑缺血再灌注模型。B组将1mlPBS经尾静脉注入大鼠体内;C组将1ml3×106个骨髓基质细胞经尾静脉注入大鼠体内;D组将1ml3×106个骨髓基质细胞源神经干细胞经尾静脉注入大鼠体内。分别在移植后7d和14d行脑灌注固定取材,应用免疫组织化学染色检测脑组织中Bcl2、Bax蛋白表达阳性的细胞,原位末端脱氧核糖核酸转移酶标记法(TUNEL)检测神经细胞凋亡数。结果C组和D组各时点的神经细胞凋亡数均少于B组(P<0.01),C组和D组移植14d时,神经细胞凋亡数显著少于移植7d时(P<0.01),移植14d时D组神经细胞凋亡数显著少于C组(P<0.05)。C组和D组Bcl2表达阳性的细胞数显著高于B组(P<0.01)。C组和D组Bax蛋白表达阳性的细胞数明显低于B组(P<0.01)。结论骨髓基质细胞源神经干细胞可能通过上调Bcl2蛋白,下调Bax蛋白的表达,减少神经细胞凋亡,从而对脑缺血再灌注损伤后的神经细胞起保护作用。

Objective To study the effects of bone marrow stromal cells derived neural stem cells on apoptosis and the expression of Bcl-2 and Bax after focal cerebral ischemia and reperfusion. Methods The model of middle cerebral artery occlusion （MCAO） and reperfusion was set up by Longa. Thirty-two Sprague-Dawley rats were divided into 4 groups： sham-operated group （A）, ischemia control group （B）, bone marrow stromal cells transplanted group （C） and bone marrow stromal cells derived neural stem cells transplanted group （D）. The rats were killed on the day 7 and 14 after transplantation. The brain sections were used for terminal deoxynucleotidyl transferase dUTP mickend labeling （TUNEL） staining and Bcl-2, Bax immunohistochemical staining. Results The number of apoptotic cells in groups C and D was decreased as compared with that in group B on the day 7 and 14 after transplantation （P〈0. 01）. The number of apoptotic cells in groups C and D on the day 14 day after transplantation was decreased as compared with that on the day 7 after transplantation （P〈0. 01）. The number of apoptotic cells in group D was decreased as compared with that in group C on the day 14 after transplantation. The positive expression of Bcl-2 in groups C and D was significantly increased as compared with that in group B on the day 7 and 14 after transplantation （P（0.01）. The positive expression of Bax in groups C and D was decreased as compared with that in group B on the day 7 and 14 after transplantation （P〈0.01）. Conclusions Bone marrow stromal cells derived neural stern cells can decrease the number of apoptotic cells after cerebral ischemia and reperfusion by up-regulating Bcl-2 and down-regulating Bax. Bone marrow stromal cells derived neural stern cells can exert the protective effect on cerebral ischemia-reperfusion injury.