骨髓间充质干细胞静脉注射移植对脑缺血大鼠脑内神经细胞增殖和分化的影响

Effects of intravenously transplanted bone marrow stromal cells on neurocyte proliferation and differentiation in the ischemic brain

目的观察骨髓间充质干细胞(bone marrow stromal cells,BMSCs)经静脉注射移植对缺血/再灌注脑内神经细胞增殖和分化的影响。方法体外培养和扩增成年雄性大鼠BMSCs;以"四管阻断法"制作大鼠前脑缺血/再灌注模型;造模后3、5、7d通过尾静脉注射Hoechst33342标记的BMSCs(2×106/1ml/只),另设对照组于相同时间点通过尾静脉注射载体溶液。于造模后4周处死大鼠,取脑切片,HE染色观察大鼠海马缺血性损伤情况;BrdU/GFAP、BrdU/MAP2和BrdU/Hoechst33342免疫荧光双标染色,观察大鼠脑内神经细胞的增殖及分化情况。结果BMSCs移植组海马CA1区存活锥体细胞数显著多于载体溶液对照组(P<0.05)。BMSCs移植大鼠脑内海马结构BrdU阳性细胞数显著多于载体溶液对照组(P<0.05),BrdU/MAP-2双标阳性细胞占BrdU阳性细胞的比例显著高于载体溶液对照组(P<0.05)。结论BMSCs经静脉注射移植能够减轻缺血性脑损伤,促进宿主脑内自体神经细胞增殖,并提高其分化为神经元样细胞的比例。

Objective To investigate the effect of intravenous administration of bone marrow stromal cells （BMSCs） on endogenous cell proliferation and differentiation in the brain after cerebral ischemia/reperfusion. Methods BMSCs from adult rats were seperated and cultured in vitro. The cultured cells were expanded and labeled by Hoechst 33342, then injected through tail vein into the rats（2 × 10^6/aml for each rat）3 d, 5d, 7d after cerebral ischemia/reperfusion. The animals injected intravenously with vehicle at the same time points were as controls. Ischemic cerebral damage was examined on brain sections with HE stain 4 weeks after cerebral ischemia/reperfusion. Cell proliferation and differentiation in the host brains were identified with BrdU/ GFAP, BrdU/MAP2 and BrdU/ Hoechst33342 immunofluorescence stain on the brain sections. Results The surviving pyramidal cells in the CA1 region of hippocampi in BMSCs transplanted animals were significantly more than those of control animals（P〈0. 05）. The number of BrdU positive cells in the brain of BMSCs transplanted animals was more than that of control animals（P〈0. 05）. The percentage of BrdU and MAP-2 double positive cells among BrdU-positive cells in BMSCs transplanted animals was significantly higher than that of control animals（P%0. 05）. Conclusions Intravenous BMSCs administration is able to ameliorate ischemic cerebral damage, promote endogenous cell proliferation and increase the neuronal differentiation of the proliferated cells in the brain.