Brain plasticity and cognitive functions after ethanol consumption in C57BL/6J mice

Area of Science:

• Neuroscience
• Epigenetics
• Alcohol Research

Background:

• High ethanol doses cause cognitive deficits and hippocampal damage.
• Moderate ethanol intake can induce epigenetic changes, specifically chromatin remodeling in brain-derived neurotrophic factor (BDNF) promoters.
• This remodeling was previously shown to enhance BDNF expression and neurogenesis in the hippocampus.

Purpose of the Study:

• To investigate the cellular and behavioral consequences of chronic, moderate ethanol consumption-induced epigenetic modifications.
• To analyze the impact of ethanol-induced chromatin remodeling on hippocampal BDNF signaling pathways and cognitive function.

Main Methods:

• Mice (C57BL/6J) underwent a 3-week chronic free-choice ethanol consumption protocol.
• DNA methylation analysis of the Bdnf gene in hippocampal subfields (CA1, CA3).
• Assessment of BDNF signaling pathways (ERK, AKT, CREB) and long-term potentiation (LTP) in the CA1.
• Behavioral testing including contextual fear conditioning, novel object recognition, and Barnes maze.

Main Results:

• Chronic ethanol consumption decreased Bdnf gene DNA methylation in the hippocampus.
• Upregulation of hippocampal BDNF signaling pathways (ERK, AKT, CREB) was observed.
• Long-term potentiation in the CA1 was not affected.
• Impairments in learning and memory were evident in contextual fear conditioning and novel object recognition tasks.
• Increased behavioral perseveration was noted in the Barnes maze, but overall spatial capacity remained unaltered.

Conclusions:

• Chronic, moderate ethanol intake induces epigenetic modifications in the hippocampus, leading to increased BDNF signaling.
• Despite enhanced BDNF signaling, ethanol consumption impairs specific learning and memory functions.
• These findings suggest that epigenetic regulation of BDNF signaling may represent an adaptive mechanism to mitigate ethanol-induced cognitive deficits.