Changes in Histone H3 Acetylation in the Rat Hippocampus Due to Severe Hypoxia and the Role of Hypoxic Postconditioning

Objective. To study the effects of severe hypobaric hypoxia followed by sessions of moderate hypobaric hypoxia using a postconditioning regime (PostC) with neuroprotective properties on the level of acetylation of histone H3 in rat hippocampal neurons. Materials and methods. A quantitative immunocytochemical method was used to study total histone acetylation and histone H3 acetylation at lysine 9 (acH3K9), which influences the conformational properties of chromatin and gene expression in the pyramidal neuron layer in hippocampal field CA1 (n = 84) in response to different hypoxia regimes. Results. Severe harmful hypoxia for four days did not lead to significant changes in the level of acetylation of acH3K9. Moderate hypobaric hypoxia in the PostC regime induced a significant increase in the acH3K9 level one day after the first session, supporting the initiation of adaptive processes induced by PostC. Conclusions. The process of histone acetylation, and particularly acetylation of histone H3, plays an important role in supporting the neuroprotective effect of hypoxic PostC.