抄録
Recent studies demonstrated that cerebral ischemia activated the proliferation and the differentiation of the endogenous neural stem cells (NSCs) in vivo. Since the lowered energy metabolism is known to mediate the ischemic effect, we examined the effect of hypoxia on the proliferation and the differentiation of NSCs in vitro. NSCs derived from the ganglionic eminence of E15.5 mice were cultured by a neurosphere method using EGF-containing medium, and exposed to various oxygen levels (20, 4, 0%O2) after mechanical dissociation. The proliferative activity of NCSs was examined by the WST-8 assay and BrdU incorporation assay, and by counting of the number of neurosphere in the presence of EGF (20ng/ml). The differentiation was induced by incubation in the 1% FBS-containing medium lacking EGF and was evaluated by the fluorescence-based immunocytochemistry and the ELISA using anti-Tuj 1 or anti-GFAP antibody. We found that in 0% O2 conditions, EGF-induced proliferation of NSCs was significantly diminished. However the treatment with 4% O2 significantly activated the proliferation when compared with 20% O2 condition. In the presence of 1% FBS, 4% O2 promoted astroglial differentiation. These results suggest that moderate hypoxia, but not severe hypoxia, activates proliferative activity and astroglial differentiation of the NSCs. [Jpn J Physiol 54 Suppl:S224 (2004)]
