Ethanol reduces expression of apoptotic proteins after hypoxia/reoxygenation in a brain slice model

Objectives: Acute administration of ethanol is associated with neuroprotection in rat with transient cerebral ischemia. To investigate the molecular mechanism of ethanol-induced neuroprotection, we determined the effect of ethanol on expression levels of apoptotic proteins, including caspase-3, Bcl-2-associated X protein (Bax), and apoptosis-inducing factor (AIF). To assess overall cell viability following ethanol treatment, ADP/ATP ratio was measured. Methods: Brain slice cultures were prepared using postnatal 10-day-old Sprage-Dawley rats. Brain slices were divided into control and hypoxia groups. Hypoxia groups include a non-treatment group and three treatment groups (10, 30, or 90 mM ethanol). Levels of caspase-3, Bax, and AIF were determined by western blot. ADP/ATP ratio was assessed using ADP/ATP assay kit. Results: Ethanol administration reduced ADP/ATP ratio in all three treatment groups (10, 30, and 90 mM). A reduction in caspase-3, BAX, and AIF expression was observed with all three treatment groups in conjunction with decreased ADP/ATP levels. The three treatment groups showed similar levels of reduction in ADP/ATP ratio and apoptotic protein expression. Discussion: Ethanol-induced neuroprotection involves inhibition of apoptotic pathways, including Bax, caspase-3, and AIF. Dose range of 10-90 mM ethanol provides similar level of protection compared to 10 mM ethanol.