Investigation of antidepressant effects of probiotic Lactobacillus rhamnosus GG

Investigation of the antidepressant effects of probiotic Lactobacillus rhamnosus GG (LGG) INTRODUCTION AND AIM: In this study, the therapeutic effects of probiotic LGG, antidepressant drugs bupropion and venlafaxine were investigated in rats with chronic unpredictable mild stress model and the results were compared. MATERIALS AND METHODS: A total of 56 male Wistar albino rats were used in the control, stress, bupropion, venlafaxine, LGG, bupropion + stress, venlafaxine + stress, LGG + stress groups, each n=7. Changes in body weights of rats during the experiment were determined by measuring weight. Four different behavioral tests were performed to evaluate depressive behaviors (sucrose preference test, three-chamber sociability test (social interaction test), elevated plus maze test, forced swimming test). Gastric pH levels were measured. 5-HT1A, DRD1, ADRA-2A, GABA-A α1, CNR1, MC4R, NR3C2, NLRP3 in hippocampus tissue; NOD1 receptor expression levels in small intestine tissue were determined by RT-PCR method. BDNF levels in hippocampus tissue were determined using the elisa kit. Histopathological examinations were performed on cortex and small intestine tissues. RESULTS: It was observed that LGG, bupropion and venlafaxine treatment caused antidepressant effects according to the results of behavioral tests (p<0.05). LGG caused antidepressant effects by increasing pH and BDNF levels, 5-HT1A, DRD1, ADRA-2A, GABA-A α1, CNR1, NOD1 receptor expression levels (p<0.05); bupropion caused antidepressant effects by increasing BDNF level, ADRA-2A, CNR1, NOD1 receptor expression levels and decreasing NLRP3 receptor expression level (p<0.05); venlafaxine caused antidepressant effects by increasing BDNF level, DRD1, ADRA-2A, GABA-A α1, CNR1 expression levels and decreasing MC4R, NLRP3 receptor expression level (p<0.05). LGG, bupropion and venlafaxine decreased neurodegeneration level and glial cell activity. CONCLUSION: LGG is a potential psychobiotic bacteria and can be used to treat depression. Keywords: Chronic stress, depression, LGG, neurodegeneration, neurotransmitter receptors