Heat-inactivated Bacillus subtilis subsp. natto strain QOL (QOL bacillus natto) improves depression-like behavior caused by social defeat stress in mice

Abstract

Recently, it has been reported that postbiotics containing inactivated microbial cells may improve depression symptoms via the gut-brain axis. In this study, the effects of heat-inactivated Bacillus subtilis subsp. natto strain QOL (QOL bacillus natto), one of the postbiotics, in a mouse model of social defeat stress were investigated. Results of the tail suspension test revealed that QOL bacillus natto supplementation improved immobility time, a quantitative indicator of depressive-like behavior, in mice subjected to 10 days of social defeat stress. These results suggest that QOL bacillus natto supplementation is useful for preventing and improving depressive symptoms caused by chronic psychological stress.