Abstract: AIM: To observe changes of intracellular free calcium levels ([Ca²⁺]_i) and neuroglobin (NGB) expression when rats′brain cells were exposed to chemical hypoxia, and the influence of aspirin (ASA) on changes as well as to study its mechanism primarily.METHODS: Sodium dihionite was used to deprive the oxygen in culture medium, and confocal laser scanning microscope with double fluorescence labeling methods were used to measure the changes of [Ca²⁺]_i and NGB expression in rats′brain cells.Flou-3/AM and Cy-3 were used to indicate calcium concentration and NGB expression respectively.RESULTS: [Ca²⁺]_i and NGB expression are related to the time of hypoxia.Compared with the normal control group, average fluorescent intensity of [Ca²⁺]_i and NGB expression in the simple hypoxia group increased gradually with the time of the exposure in hypoxia.Moreover, there is the positive correlation between [Ca²⁺]_i and NGB expression.[Ca²⁺]_i and NGB expression in the ASA pretreated group increased slowly, the increase degree is significantly lower than that in the simple hypoxia group.[Ca²⁺]_i and NGB expression in the ASA treated group were increased significantly in early stage, the increase degree is not significant diffexence from the simple hypoxia group.At 120 min, [Ca²⁺]_i and NGB expression in the ASA treated group increased slowly, the increase degree is significantly lower than that in the simple hypoxia group.CONCLUSION: ASA has a protective effect on hypoxic injury of rats′ brain cells, which may be attribute to its inhibiting calcium overload, and NGB expression is regulated by Ca²⁺-CaM complex.In addition, the neuroprotective effects of ASA pretreated group were better than ASA treated group in early stage.

Key words: aspirin, brain, cell culture, hypoxica, [Ca²⁺]_i, neuroglobin