骨髓间充质干细胞向神经细胞定向分化的体外研究

STUDY ON THE DIFFERENTIATION OF MARROW STROMAL STEM CELLS INTO NEURAL CELLS IN VITRO

目的 探讨骨髓间充质干细胞( marrow stromal stem cells,MSCs)向神经细胞定向分化中神经蛋白分子的表达情况。 方法 取第5～7代体外培养Wistar大鼠MSCs,以0 .5μmol/ L全反式视黄酸( all- trans retinoidacid,ATRA)预诱导2 4 h后,换用改良神经细胞培养基( modified neuronal medium,MNM)继续培养。在ATRA作用2 4 h及MNM作用2、6、9、18及36 h,免疫组织化学检测巢蛋白( Nestin)、神经元特异性核心抗原( neuron- specificnuclear protein,Neu N)、微管相关蛋白2 ( microtubule- associated protein 2 ,MAP- 2 )和胶质纤维酸性蛋白的表达情况。 结果 ATRA和MNM作用后,MSCs呈典型神经元样,伸出较多的突起和分支,形成网络。Nestin最先表达,ATRA作用2 4 h出现,Neu N其次,MNM作用2 h检测到,MAP- 2最晚,MNM作用9h检测到。Nestin在MNM作用18h后表达最强,其阳性率为92 .3%±3.4 % ;36 h后表达明显减弱,阳性率仅为12 .3%±3.4 % ,而其它标志蛋白则持续表达。 结论 ATRA和MNM能促进MSCs向神经前体细胞和神经元转化,神经蛋白分子的表达顺序与神经细胞发育过程一致。

Objective To investigate the neural markers' expression in the differentiation of marrow stromal stem cells(MSCs) into neural cells. Methods Rats MSCs were expanded as undifferentiated cells in vitro for 5 to 7 generations and cultured in a modified neuronal medium(MNM) after 24 hours of all trans retinoid acid(ATRA) pretreatment. Immunocytochemistry was used to detect the expression of nestin、neuron specific nuclear protein(NeuN)、microtubule associated protein 2 (MAP 2) and glial fibrillary acidic protein(GFAP) at different timepoints. Results After ATRA and MNM treatment, MSCs progressively assumed neuronal morphological characteristics. Nestin occurred first after 24 hours of ATRA treatment; then NeuN expressed after 2 hours of MNM treatment; the last one was MAP 2 and it was detected after 9 hours of MNM treatment. Other markers continuously expressed except that the expression of nestin peaked after 18 hours of MNM induction and remarkably decreased after 36 hours. Conclusion ATRA and MNM could promote the differentiation of MSCs into neural cells and the expression of neural specific markers was consistent with current knowledge regarding the timepoints of markers expression in the neuronal development which provides a good model in vitro for neuronal development research.