Antidepressant-like effects of Lactobacillus plantarum DP189 in a corticosterone-induced rat model of chronic stress

Probiotic antidepressant effects demonstrated previously in clinical studies and animal models act via unknown mechanisms. Here we used a corticosterone injection-induced Sprague-Dawley rat chronic stress exposure model to investigate antidepressant-like effects of potential probiotic Lactobacillus plantarum DP189 (DP189) isolated from Chinese traditional fermented sauerkraut. After administration of DP189 (1.0 x 10(9)CFU/d) suspension by gavage for 21 days, behavioral, histopathological and biochemical changes were assessed, including hippocampal neuronal apoptosis assessments via TUNEL staining and Western blot analysis. Behaviorally, DP189 treatment improved memory and spatial learning and reduced anhedonia, as measured using Morris water maze and sucrose preference tests, respectively. Histopathologically, DP189 treatment ameliorated hippocampal pathological changes and dramatically reduced TUNEL-positive cell numbers. Biochemically, DP189 decreased serum IL-1 beta and TNF-alpha levels, decreased hippocampal mitogen-activated protein kinase kinase 7 and c-Jun N-terminal kinase 2 levels, down-regulated pro-apoptosis protein Bax immunocontent and up-regulated antiapoptosis protein Bcl-2 immunocontent. Collectively, these results suggest that DP189 treatment may prevent and/or alleviate depression-like behaviors and hippocampal neural injury induced by CORT.