Objective To evaluate the role of sirtuin 1 (SIRT1) in sevoflurane (Sev) combined with nitrous oxide (N₂O) anesthesia-induced apoptosis of primary-cultured hippocampal neurons.

Methods The primary-cultured hippocampal neurons were incubated with 1.3% Sev and 50% N₂O for 2 h, while the control cells were incubated with 50% oxygen. To further investigate the role of SIRT1, the hippocampal neurons were pretreated with SIRT1 antagonist sirtinol (50 μmol/L), salermide (50 μmol/L), or activator resveratrol (100 μmol/L) for 24 h before anesthesia. After 24 h, the hippocampal neurons were collected, then Western blotting analysis was performed to assess the expressions of SIRT1-p53 pathway-related proteins including Bax, cleaved caspase-3 (c-caspase-3), cleaved poly (ADP-ribose) polymerase (c-PARP), phosphorylated H2A histone family member X (γ-H2AX), SIRT1, and acetylated p53 (lysine 381) (acetyl-p53). The distributions and expressions of c-caspase-3, SIRT1, and acetyl-p53 were detected by immunofluorescence staining.

Results The protein levels of pro-apoptotic Bax, c-caspase-3, c-PARP, and DNA damage marker γ-H2AX were increased in primary hippocampal neurons after Sev-N₂O anesthesia (P < 0.05). Moreover, Sev-N₂O anesthesia resulted in the up-regulation of SIRT1 protein level and the down-regulation of acetyl-p53 protein level (P < 0.05). The pretreatment with SIRT1 antagonist sirtinol or salermide could inhibit SIRT1 expression, but further enhance the expressions of Bax, c-caspase-3, c-PARP, and γ-H2AX induced by Sev-N₂O anesthesia (P < 0.05). However, the pretreatment with SIRT1 activator resveratrol presented the opposite results (P < 0.05).

Conclusions The activation of SIRT1-p53 pathway can inhibit Sev-N₂O anesthesia-induced apoptosis of primary hippocampal neurons.