巢蛋白和阶段特异性胚胎抗原-1在大鼠2型星形胶质细胞中的表达

目的 观察1型和2型星形胶质细胞(T1A、T2A)是否表达神经干细胞的标志物、是否具有神经干细胞的特性.方法 取新生大鼠脑皮质,体外培养纯化的O-2A祖细胞、T1A和T2A,应用激光共焦双重免疫荧光标记技术检测巢蛋白和阶段特异性胚胎抗原-1(SSEA-1)的表达;观察O-2A祖细胞、 T1A和T2A在碱性成纤维生长因子(bFGF)和表皮生长因子(EGF)的培养液中生长方式的改变.结果 巢蛋白在O-2A祖细胞和T2A中表达,T1A不表达;SSEA-1仅在T2A中表达.在干细胞培养基中培养10d,T2A形成能增殖和连续传代的细胞球,细胞球巢蛋白标记阳性,贴壁后分化细胞具有神经元、星形胶质细胞和少突胶质细胞样形态;但相同培养条件下的O-2A祖细胞和T1A生长方式无改变.结论 巢蛋白和SSEA-1在两型星形胶质细胞中的表达存在差异,T2A具有神经干细胞的某些生物学特性.

THE EXPRESSION OF NESTIN AND SSEA-I IN THE RAT TYPE-2 ASTROCYTES

Objective To investigate whether type-1 and type-2 astrocytes(T1A,T2A) express the characteristic molecules of neural stem cells. Methods Purified cultures of cortical O-2A progenitor cells,T1A and T2A were prepared from neonatal rats.The expression of nestin and stage specific embryonic antigens-1(SSEA-1) were detected by immunocytochemistry labeling.O-2A progenitor cells,TIA and T2A were cultured in the presence of basic fibroblast growth factor(bFGF) and epidermal growth factor(EGF) for 10 days.Then the morphological changes of the above cells were examined. Results Expression of nestin was observed in O-2A progenitor cells and T2A,while T1A was negative for nestin immunostaining.Expression of SSEA-1 was only detected in T2A.After treated with bFGF and EGF,T2A changed into neurospheres-like morphology and could be passaged continuously.The spheres were also positive for nestin immunolabeling.After plated onto PLL-coated substrates for 10 days,cells with typical morphologies of neuron,astrocytes and oligodendrocytes were observed to migrate from the spheres.Conclusion Nestin and SSEA-1 were expressed differently in T1A and T2A.T2A induced by extracellular signals may acquire some properties of the multipotent neural stem cells.