A Synbiotic Mixture Ameliorates Depressive Behavior Induced by Dexamethasone or Water Avoidance Stress in a Mouse Model.

Abstract

Disruption of the hypothalamic-pituitary-adrenal axis by stress and glucocorticoid drugs is a major cause of depression. The benefits of probiotics may extend to systems beyond the gastrointestinal tract, i.e., the central nervous system. Therefore, the effect of a synbiotic (probiotic + prebiotic) mixture on dexamethasone (Dex) and stress-induced depression was investigated. Male albino mice were used, the forced swimming test (FST) measured despair, and the sucrose preference test measured anhedonia. The synbiotic regimen (12.5x106 CFU) was supplemented in drinking water for 7 days. Dex was administered subcutaneously either in a single dose on the test day or for 7 days. Water avoidance stress (WAS) was induced for 1 hour each day for 4 days. Drinking the synbiotic reduced immobility time during the FST (54±7 sec vs. 111±6 sec in the control water group, p<0.001). Dex injection significantly increased the immobility time (single dose: 166±6 sec and 7 days: 174±9 sec) compared with the control groups, while adding the synbiotic to their drinking water reduced it (single dose: 81±6.6 sec, and 7 days: 84±14 sec), indicating that the synbiotic reversed Dex-induced depression. WAS increased the immobility time (148±11 sec vs. sham 99±6 sec, p<0.001) in the FST test. When the synbiotic treatment was added following WAS, the immobility time decreased (81±6.5 sec). The synbiotic groups also had a higher sucrose preference percentage. The synbiotic mixture prevented the effects of WAS, acute or sub-acute Dex-induced depression in mice. Therefore, probiotics might be useful and safe supplements to prevent depression related to stress or glucocorticoid therapies, a phenomenon that deserves further evaluation.