Hypobaric hypoxia induces high expression of neuroglobin in rat cerebral cortical neurons / 中华神经医学杂志

ABSTRACT

Objective To explore the changes in neuroglobin(NGB)expression in rat cerebral cortex induced by acute and chronic hypoxia at high altitude.Methods Seventy SD rats were randomly divided into normal control and experimental groups,and in the latter group,the rats kept in a high-altitude research base in Kekexili(4600 m),while the control rats were kept in a facility at the altitude of 2295 m.The rats in the experimental group were divided into 6 groups with the exposure time of 12,24,48,72 h,1 week and 1 month.An oximeter was used to measure the SaO2 level.Semi-quantitative PCR and Western blotting were performed to detect the expression levels of NGB mRNA and protein in the cortical neurons of the rats after the exposure.Results After explosure of the rats to hypoxia at high altitude for 12h,the SaO2 was lowered to(70.70±2.83)%and increased gradually as exposure time prolonged,but remained lower than that in the control group throughout the exposure.RT-PCR showed a rapid increase of NGB mRNA expression after 24-h exposure to hypoxia,followed by gradual decrease till recovery of the normal level at 1 week;the expression slowly increased after 1 week and maintained a high level till 1 months.showing significant difference from that in the control group(P＜0.05).Western blotting showed an identical pattem of NGG protein expression alterations during the experiment.Conclusion NGB expressions in the cerebral cortex increase significantly after acute and chronic hypoxia at an altitude of 4600 m to enhance the tolerance to hypobaric hypoxia,suggesting the possible role of NGB as an important endogenous mechanism for protecting the neural tissues against hypoxic injuries.