Effects of oxygen concentration on the proliferation and differentiation of mouse neural stem cells in vitro
Effects of oxygen concentration on the proliferation and differentiation of mouse neural stem cells in vitro
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DOI：
10.1007/s10571-007-9237-y
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发表时间：
2008-09-01
影响因子：
4
通讯作者：
Shinohara, Kazuyuki
中科院分区：
文献类型：
--
作者：
Horie, Nobutaka;So, Kenji;Shinohara, Kazuyuki
背景和目的已知脑缺血会引起神经干细胞（NSC）的激活；但其机制尚未完全确定。尽管已知氧浓度可介导许多缺血作用，但很少有人关注脑缺血下病理性氧变化对 NSC 激活的作用。我们在体外研究了不同氧气浓度对小鼠神经干细胞的影响。方法采用神经球法从胚胎第15.5天的胎儿ICR小鼠神经节隆起培养NSCs。分别通过溴脱氧尿苷（BrdU）掺入、免疫细胞化学和TUNEL测定评估氧浓度对NSC增殖、分化和细胞死亡的影响。结果在2%氧气中观察到NSCs的增殖和神经元分化最高，与20%和4%氧气相比，BrdU标记细胞和Tuj1阳性细胞的比例显着更高。另一方面，除了缺氧（0％氧气）的情况外，星形胶质细胞的分化不受氧气浓度的影响。神经干细胞的细胞死亡在低氧条件下增加，并在缺氧时达到峰值。此外，在低氧条件下观察到神经元亚型分化从 GABA 阳性神经元向谷氨酸阳性神经元的转变。结论 这些发现提出了脑缺血引起的氧水平降低增强 NSC 增殖和神经分化的可能性，并且已知发生在缺血半暗带的轻度缺氧（2% 氧）适合丰富的神经元分化。
Background and purpose Cerebral ischemia is known to elicit the activation of neural stem cells (NSCs); however its mechanism is not fully determined. Although oxygen concentration is known to mediate many ischemic actions, there has been little attention given to the role of pathological oxygen changes under cerebral ischemia on the activation of NSCs. We investigated the effects of various oxygen concentrations on mouse neural stem cells in vitro. Methods NSCs were cultured from the ganglionic eminence of fetal ICR mice on embryonic day 15.5 using a neurosphere method. The effects of oxygen concentrations on proliferation, differentiation, and cell death of NSCs were evaluated by bromodeoxyuridine (BrdU) incorporation, immunocytochemistry, and TUNEL assay, respectively. Results The highest proliferation and the neuronal differentiation of the NSCs were observed in 2% oxygen, which yielded significantly higher proportions of both BrdU-labeled cells and Tuj1-positive cells when compared with 20% and 4% oxygen. On the other hand, the differentiation to the astrocytes was not affected by oxygen concentrations, except in the case of anoxia (0% oxygen). The cell death of the NSCs increased in lower oxygen conditions and peaked at anoxia. Furthermore, the switching of the neuronal subtype differentiation from GABA-positive to glutamate-positive neurons was observed in lower oxygen conditions. Conclusions These findings raise the possibility that reduced oxygen levels occurring with cerebral ischemia enhance NSC proliferation and neural differentiation, and that mild hypoxia (2% oxygen), which is known to occur in the ischemic penumbra, is suitable for abundant neuronal differentiation.