Cognitive and synaptic plasticity in the hippocampus exposed to stress respond similarly to different probiotic mixtures.

It has been proven that while stressors change the quantity and quality of gut microbes, probiotic bacteria repair the intestinal flora. We evaluated the effect of different probiotic mixtures on cognitive function, synaptic plasticity, and some biochemical factors in a rat model of chronic unpredictable mild stress (CUMS). Animal groups included the control rats (CON), rats exposed to CUMS (STS), and three groups of stressed animals with different probiotic regimens. Cognitive behavior, hippocampal synaptic plasticity, and serum oxidant/antioxidant factors were evaluated. Whereas the CUMS disrupted the spatial learning and memory, the probiotic administration improved behavioral functions. While the CON rats displayed a robust plasticity, their STS counterparts did not. The probiotics restored the synaptic plasticity in all stressed groups. CUMS also led to a decrease in antioxidants and an increase in oxidants, but probiotic treatment improved these changes. It appears that the various probiotic cocktails have a similar effect on hippocampus-dependent cognition and synaptic plasticity, as well as on oxidant/antioxidant factors.