Innate immune tolerance against adolescent intermittent alcohol exposure-induced behavioral abnormalities in adult mice.

It has been reported that pre-stimulation of the innate immune system in animals can prevent chronic stress-induced depression- and anxiety-like behaviors in animals, suggesting the possibility that innate immune stimulants may prevent the pathogenesis of neuropsychiatric disorders. Alcohol use, especially when it begins in adolescence, is a risk factor for the development of neuropsychiatric disorders in adulthood. Preventing the pathological changes induced by alcohol exposure in adolescence could be of great importance for improving human mental health. Here, we investigated whether pre-stimulation of the innate immune system can prevent the behavioral abnormalities in a disease model induced by adolescent intermittent alcohol exposure (AIE). The results showed that a single injection of lipopolysaccharide (LPS) injection (100 μg/kg) one day before alcohol exposure prevented the AIE-induced depression- and anxiety-like behaviors in the tail suspension test, forced swimming test, sucrose preference test, elevated pluz maze test, light-dark test, and open field test in adult mice. Single LPS injection (100 μg/kg) before alcohol exposure also transformed the AIE-induced neuroinflammatory responses in the hippocampus and prefrontal cortex in adult mice to an anti-inflammatory phenotype. Suppression of the innate immune response by minocycline pretreatment abolished the preventive effect of LPS on AIE-induced abnormalities and neuroinflammatory responses in the hippocampus and prefrontal cortex in adult mice. These results indicate that pre-stimulation of the innate immune system may prevent the AIE-induced depression- and anxiety-like behaviors in adult mice by preventing neuroinflammation. This may help to develop new strategies to prevent neuropsychiatric disorders induced by adolescent alcohol exposure.