体内外环境对骨髓间充质干细胞向神经细胞分化的影响

Effects of environment in vivo and in vitro on the differentiation of bone mesenchymal stem cells into neural cells

目的 :探讨体内外环境对骨髓间充质干细胞 (MSCs)向神经细胞分化的影响。方法 :①DAPI体外标记MSCs后 ,直接注入大鼠大脑中动脉梗塞 (MACO)模型 (n =6 )的脑内 ,2周后取脑组织 ,用免疫荧光检测MSCs来源细胞的巢蛋白 (nestin)、微管相关蛋白 - 2 (MAP - 2 )、胶质纤维酸性蛋白 (GFAP)的表达。②体外用全反式视黄酸 (ATRA)预诱导 2 4h后 ,换用改良的神经细胞培养基 (MNM )培养 18h ,免疫组化检测nestin、MAP - 2、GFAP的表达。结果 :①植入 2周后 ,MSCs在注射部位及其周围广泛分布 ,仅有少许细胞表达nestin、MAP - 2和GFAP。②MSCs在体外诱导后 ,nestin、MAP - 2的阳性率分别为 (92 .3± 3.4 ) %和 (89.6 +3.3) % ,但不表达GFAP。结论 :MSCs在脑内向神经细胞转化的转化率较低 ,而在体外转化为神经元的转化率相当高 ,体内外环境对MSCs向神经细胞的分化的过程及机理存在较大差异。

Objective:To investigate the effects of environment in vitro and in vivo on the differentiation of bone mesenchymal stem cells (MSCs) into neural cells.Methods:①MSCs were labeled with 4,6-diamidino-2-phenylindole (DAPI) and injected into the right brain of the rats(n=6),which had suffered from middle cerebral artery occlusion(MACO) a day before.Two weeks later,immunofluorescent staining was used to detect the expression of nestin,microtubule-associated protein 2 (MAP-2) and glial fibrillary acidic protein (GFAP).②In vitro,MSCs were cultured with modified neuronal medium(MNM)for 18 hours after being pretreated with 0.5umol/L all-trans retinoid acid (ATRA) for 24 hours.Immunocytochemistry was used to detect the expression of nestin,MAP-2 and GFAP.Results:①After being injected into rats for 2 weeks,MSCs survived in the ischemic areas and a few cells expressed nestin,MAP-2 and GFAP respectively.②In vitro,after ATRA and MNM treatment,the positive percentage of nestin and MAP-2 were (92.3±3.4)% and (89.6±3.3)% respectively,but no expression of GFAP was detected.Conclusion:The different ratio of MSCs differentiating into neural cells suggests that there is difference in the process and mechanism between environment in vitro and in vivo.