Effect of Lactobacillus rhamnosus on emotional behavior in high-fat diet fed mice

The prevalence of depression and associated mood disorders is higher in diabetic patients compared to healthy humans. Contributing factors might be deteriorated dopamine signaling, increased inflammation or an overactivation of the hypothalamic-pituitary-adrenal axis. These factors are also linked to an intestinal dysbiosis. Interestingly, preventive intake of probiotic lactobacilli to improve dysbiosis has been shown to improve mood and metabolism. Yet, the potential, therapeutic role of Lactobacillus rhamnosus ATCC 53103 (53103) to improve emotional behavior in diet-induced obese conditions is unknown and was investigated in this study.

Male C57BL / 6N mice were fed either a low-fat diet (LFD, 10 % kcal from fat) or an HFD (45 % kcal from fat) for 6 weeks and subsequently received daily oral gavage of either vehicle or 1x10^8 CFU 53103 for 7 weeks. Emotional behavior was assessed using Open Field Test (exploration), Dark-Light Box Test (anxiety), Elevated X Maze (stress-induced anxiety) and Mouse Tail Suspension Test (depressive-like behavior). Plasma hormone levels were assessed using ELISA and gene expression analysis was conducted using qPCR.

We observe that HFD-fed male mice develop obesity, hyperinsulinemia and -leptinemia. Neither HFD-feeding nor 53103 treatment affect exploration, anxiety, stress-induced anxiety or plasma corticosterone. Strikingly, 53103 decreases immobility time in HFD-fed mice showing improved depressive-like behavior. In the nucleus accumbens, a brain region involved in dopaminergic signaling, 53103 reverts HFD-induced decrease of tyrosine hydroxylase, which is the rate-limiting enzyme in dopamine synthesis.

Our data indicate that 53103 can specifically decrease depressive-like behavior in HFD-fed male mice with a molecular signature of ameliorated dopamine synthesis.

Publication History

Article published online:
06 May 2021