Lactobacillus reuteri ATG-F4 alleviates behavioral impairment induced by chronic stress.

Chronic stress impairs quality of life by disturbing physical and psychological functioning, and increases susceptibility to a wide range of diseases. Lactobacillus reuteri ATG-F4 isolated from the fecal samples of a newborn baby alleviated chronic stress-induced anhedonia by altering the expression of neurometabolites and neurotransmitter receptors. In this study, we examined whether ATG-F4 can improve behavioral deterioration induced by chronic stress using the Laboratory Animal Behavioral Observation Registration and Analysis System (LABORAS). The continuous behavior of the mice was examined in the LABORAS cage without the intervention of the researchers. Mice exposed to chronic stress displayed significantly increased frequency of immobility compared with control mice, whereas the duration of immobility remained unchanged. Interestingly, mice treated with ATGF4 during stress treatment period and two weeks prior maintained immobility frequency at control level observed in control mice. Locomotor activity and exploratory behavior of mice exposed to chronic stress were significantly attenuated, but ATG-F4 treatment restored them at control levels. Stress is known to adversely affect sleep quality. Electroencephalography analysis revealed that sleep latency enhanced in stressed mice was reduced by ATG-F4 administration. RT-PCR analysis of brain tissues demonstrated that ATG-F4 intake modulated the expression of multiple genes including GABA receptor and serotonin receptor. Alterations in gut microbiota composition and bacterial diversity induced by chronic stress were restored to levels similar to controls by ATG-F4 treatment. Taken together, these results suggest that ATG-F4 can ameliorate chronic stress-induced behavioral impairments, potentially via its effects on gene expression and the composition of the gut microbiota.