Interaction Between Social Defeat Stress and Chronic Ethanol Exposure on Behaviors During Ethanol Withdrawal and Pro-Inflammatory Cytokines in Mice

Stress and ethanol consumption are known to affect the immune system, interfering in individual health, and resistance to opportunistic diseases. When experienced together, stress and ethanol seem to interact uniquely, altering each other effects depending on the exposure schedule. However, the effects of social stress on chronic ethanol exposure effects on the immune system are not well elucidated. To study this interaction, we chronically treated male swiss mice with ethanol after repeated social defeat stress (SDS) exposure. Some animals were tested in the elevated plus-maze (EPM) and open field (OF) while another cohort had plasmatic TNF-α, TGF-β1, CXCL-1, CCL-2, and VEGF quantified. Mice exposed to SDS or ethanol withdrawal showed increased anxiety-like behaviors in the EPM, while ethanol withdrawal decreased locomotor activity. Both alterations were attenuated in the groups exposed to SDS and ethanol withdrawal. Ethanol and stress alone increased plasmatic CXCL-1, while only stress affected CCL-2 and VEGF. Our results suggest that SDS exposure and ethanol withdrawal attenuated the increase in anxiety-like behaviors, but did not alter each other effects on cytokine content.