FIGURE 1.

Experimental design. Representation of the study design. C57BL/6 mice were fed for a total of 4 weeks with a mixture of three probiotics (Lactobacillus helveticus R0052, L. plantarum R1012, and Bifidobacterium longum R0175), the antidepressant fluoxetine, or saline. After 4-week treatment, animals underwent a battery of testing relevant to anxiety. All groups were sacrificed on the same day. Cecal contents and the entire hippocampus tissue were harvested for further analysis. SPT, sucrose preference test; EPM, elevated plus maze; FST, forced swim test; CMS + NS, subjected to the CMS procedure and received saline; CMS + F, subjected to the CMS procedure and received fluoxetine; CMS + P, subjected to the CMS procedure and received probiotics; CON + NS, not subjected to any stress and received saline; CON + F, not subjected to any stress and received fluoxetine; and CON + P, not subjected to any stress and received probiotics.