Chronic stress contributes to long-term isoflurane anesthesia-induced cognitive dysfunction via histone acetylation modulated by RbAp48-HDAC2 in male mice.

Abstract

Background: Histone deacetylation has been shown to be related to memory decline in aging and neurodegenerative diseases. Chronic stress, which has been shown to induce histone deacetylation, is associated with cognitive impairment. In this study, we hypothesized that histone deacetylation induced by chronic stress contributes to cognitive dysfunction after long-term isoflurane anesthesia.

Methods: A mouse model of 6-h isoflurane anesthesia was established. The repeated social defeat stress (RSDS) mouse model was established by repeated socialization of aggressive CD-1 mice and C57 mice. Plasma corticosterone levels were measured by ELISA assay. Cognitive function was assessed by the fear condition test. RbAp48-overexpression adenovirus was injected into the ventricles of mice and transfected into primary hippocampal neurons to enhance of RbAp48 expression. Immunofluorescence was employed to detect viral fluorescent protein expression. The expression levels of retinoblastoma-associated protein 48 (RbAp48), histone deacetylase 2(HDAC2), acetylation of H3K9 and H4K12 and brain-derived neurotrophic factor (BDNF) were detected by Western blot. Co-Immunoprecipitation (Co-IP) and Western blot were used to detect the interaction between RbAp48 and HDAC2.

Results: Mice inhaling isoflurane for 6 h exhibited more severe impairment of contextual fear memory and sustained elevation of plasma corticosterone levels compared to control group mice. Notably, RSDS mice demonstrated similar behavioral and plasma corticosterone patterns post-isoflurane anesthesia compared to anesthesia group and control group mice, accompanied by decreased acetylation of H3K9 and H4K12, reduced RbAp48 expression, elevated HDAC2 levels, and enhanced RbAp48-HDAC2 interaction. Overexpression of RbAp48 effectively ameliorated these alterations both in vivo and in vitro. RbAp48 overexpression enhanced hippocampal BDNF expression and attenuated the contextual fear memory deficits induced by the RSDS mice following 6-h isoflurane anesthesia.

Conclusions: Perioperative chronic stress exacerbates cognitive dysfunction after 6-h long-term isoflurane anesthesia. The activity of RbAp48/HDAC2-induced histone deacetylation modification plays a critical role in these negative effects on cognition.