嗅鞘细胞对神经干细胞增殖与分化的影响

观察嗅鞘细胞(OECs)对神经干细胞(NSCs)增殖与分化的影响。取孕14d的SD胚鼠嗅球和腹侧中脑组织,分为OECs+NSCs共培养组和NSCs单独培养组进行培养。用p75免疫组化法,p75、BrdU/nestin、GFAP、NF(神经原纤维)和p75/nestin免疫荧光法分别鉴定OECs和NSCs并观察其增殖与分化。在培养7d时,绝大多数OECs呈梭形且发出2~3个突起,少量呈扁平椭圆形,两者均呈p75阳性。在7d时,单独培养的NSCs表现为典型的神经球悬浮生长,呈BrdU/nestin阳性;14d后偶见神经球贴壁分化,球中的少数细胞呈绿色荧光标记的NF阳性,大部分呈GFAP阳性。在5d时,OECs+NSCs共培养组形成神经球;10d时球体积不断增大,球心透亮度良好;12d后神经球的体积不再增大,开始贴附在OECs上生长,可见神经球向四周伸出突起并开始分化;14d时NSCs紧贴OECs生长并同OECs广泛交织在一起,可见NSCs和OECs分别呈nestin和p75阳性,NSCs中的大部分呈NF阳性,小部分为GFAP阳性。NSCs单独培养组和OECs+NSCs共培养组中NF阳性细胞率分别为47.2%和69.5%,前者明显少于后者(P<0.05)。以上研究结果提示OECs有促进NSCs增殖和诱导其分化的作用。

EFFECTS OF OLFACTORY ENSHEATHING CELLS ON PROLIFERATION AND DIFFERENTIATION OF NEURAL STEM CELLS

To investigate the effects of olfactory ensheathing cells (OECs) on proliferation and differentiation of neural stem cells (NSCs). NSCs and OECs were separated from ventral midbrain and olfactory bulb from embryonic rats aged 14 days. The cells were divided into two groups: NSCs co-cultured with OECs group (group A) and NSCs cultured solely (group B). The proliferation and differentiation of NSCs and OECs were identified by p75 immunochemistry and immunofluorescence histochemical staining for p75, BrdU/nestin,GFAP,NF,p75/nestin, respectively. On the 7th day, most of OECs showed p75 immunopositive staining. NSCs formed typical floaty neurospheres on the 7th day, which exhibited immunofluorescence reactivities for BrdU/nestin. On the 14th day, some neurospheres in group B were prone to differentiation. Most of the cells were GFAP positive, while few of them were NF positive. The neurospheres in group A accreted on OECs, stretched its tubules and began to differentiation from the 12th day. On the 14th day, both kinds of cells clustered together intensively. Nestin positive NSCs and p75 positive OECs were encountered. GFAP and NF staining showed that the majority of them were NF positive cells, the remaining ones were GFAP positive. Percentage (69.5%) of the NF positive cells in group A was more than that in control group (47.2%) (P< 0.05). The present results indicate that OECs can promote the proliferation and differentiation of NSCs.