神经干细胞的端粒酶活性与其增殖分化的关系

Relationship of telomerase activity with proliferation and differentiation in neural stem cells

目的探讨体外培养的神经干细胞端粒酶活性与细胞增殖、分化的关系,以及细胞分化后端粒酶逆转录酶的表达情况。方法采用无血清培养法从新生大鼠脑皮质分离培养神经干细胞；通过免疫荧光细胞染色鉴定神经干细胞；细胞计数法检测细胞的增殖情况；TRAP-ELISA法测定神经干细胞的端粒酶活性：RT-PCR法和Western-blot法测定细胞分化前后的端粒酶逆转录酶的表达。结果从新生大鼠脑皮质分离培养的神经干细胞具有端粒酶活性；体外培养12周内,神经干细胞的端粒酶活性未见变化,细胞的增殖速率亦未见明显不同；神经干细胞分化后端粒酶活性丧失,端粒酶逆转录酶的mRNA和蛋白质也均未见表达。结论在体外培养过程中,大鼠脑神经干细胞的端粒酶活性和细胞增殖速率未见变化；神经干细胞分化后端粒酶活性丧失,可能是由于端粒酶逆转录酶停止表达所致。

Objective To investigate that relationship of the telomerase activity with proliferation and differentiation in neural stem cells （NSCs） cultured in vitro and the expression oftelomerase reverse transcriptase （TERT） in NSCs after differentiation. Methods NSCs were isolated from the cerebral cortex of neonatal rat and cultured in serum-free medium. They were identified by immunofluorescence staining. The proliferation and telomerase activitise of NSCs were measured by cell counting and TRAP-ELISA respectively. The expression of TERT in NSCs after differentiation was determined by RT-PCR and Western-blot. Results NSCs were isolated from neonatal rat cerebral cortex and cultured in serum-free medium. They were identified by immunofluorescence staining. The proliferation and telomerase activitise of NSCs were measured by cellular counting and TRAP-ELISA respectively. The expressions of TERT in NSCs after differentiation were determined by RT-PCR and Western-blot. Conclusion No change was showed in proliferation speed and telomerase activity of NSCs during culture in vitro. The telomerase activity was lost after NSCs differentiation, which may be caused by the cease of TERT expression.