Lactobacillus fermentum ATCC 9338 Supplementation Prevents Depressive-Like Behaviors Through Glucocorticoid Receptor and N-Methyl-D-aspartate2b in Chronic Unpredictable Mild Stress Mouse Model.

Depression is a long-term, related to stress neuropsychiatric disorder, leading to psychological health issues including worthlessness, anhedonia, sleep and appetite disturbances, dysregulated HPA axis, neuronal cell death, and alterations in the gut microbiota (GM). Dysregulated HPA axis increases level of glucocorticoids that induce proinflammatory response with activation of abnormal kynurenine pathway via metabolizing indoleamine-2,3-dioxygenase (IDO). Kynurenine pathway leads to excitotoxicity of N-methyl-D-aspartate (NMDA) receptor responsible for neuronal cell death. Further, probiotics supplementation gained attention from researchers and clinicians to treat neuropsychiatric diseases. GM alteration remains a key reason for depression; however, there is limited information about the role of probiotics on depression involving glucocorticoid receptor and NMDA excitotoxicity through IDO. Chronic unpredictable mild stress (CUMS) model was prepared to check the role of Lactobacillus fermentum ATCC 9338 (LF) and 1-methyl-D-tryptophan (1-MT) in depression. Herein, mice were placed into experimental groups: control, CUMS stressed, CUMS vehicle, CUMS LF, CUMS 1-MT, and CUMS UT (untreated). Results showed that peroral administration of 1 × 10