突触蛋白-Ⅰ在胚胎干细胞体外神经分化过程中的表达变化

目的探讨突触蛋白-I（synapsin-I）在胚胎干细胞（ESCs）体外神经分化过程中的表达变化及作用。方法采用“五步法”和维甲酸（RA）法两种途径体外诱导ESCs向神经细胞分化，并以另一种可向神经细胞分化的肿瘤细胞-PC12细胞的诱导过程作参照，从不同的途径、不同的细胞进行比较．通过免疫组织化学、RT-PCR、Western blot方法观察这一过程中synapsin-I的表达变化．找出synapsin-I在ESCs向神经细胞分化过程中表达变化的共同规律。结果结合形态学和其它神经特异性指标的变化，synapsin-I在ESCs和PC12细胞向神经细胞分化的过程中具有早期即有表达，后逐渐升高，至分化成熟阶段达最高，后期又逐渐下降的变化规律。结论在ESCs的分化过程中，synapsin-I的表达存在特定的时空规律，并与ESCs的形态学改变相关，提示synapsin-I可能对ESCs在神经分化过程中的形态分化起着重要的作用。

Changes of synapsin- Ⅰ expression during neural differentiation of embryonic stem cells in vitro

Objective To study the role of synapsin- I during the differentiation of embryonic stem cells (ESCs) into the neuron. Methods Neural differentiation of ESCs was induced by two approaches: the five-step approach and the retinoic acid (RA) approach. A tumor cell line called PC 12 cell which can also differentiate into neural cells was used as a control group. Synapsin- I expression was assessed by immunohistochemistry, semi-quantitative RT-PCR and Western blot analysis respectively at different time points. Common rule of synapsin- I expression during neural differentiation was established by analyses between different cell lines and different inducing approaches. Results Immunohistochemistry, semi-quantitative RT-PCR and Western blot analysis combined with morphology and other neural specific markers showed that synapsin- I expression during neural differentiation between different cell lines and different approaches had a common rule: synapsin- I appeared at the early stage, then increased progressively, and reached a plateau at the full-differentiation stage, after that, declined slowly at the late stage. Conclusion Synapsin-I expression of ESCs exhibits a special time and space rule during its neural differentiation and is related to its morphological change, which suggests that synapsin- I plays an important role in the morphological differentiation during ESCs neural differentiation.