Mahsa Hadizadeh - Physiology Research Center, Kashan University of Medical Sciences, Kashan, Iran
Gholamali Hamidi - Physiology Research Center, Kashan University of Medical Sciences, Kashan, Iran
Mahmoud salamim - Physiology Research Center, Kashan University of Medical Sciences, Kashan, Iran

Objective(s): Prenatal stresses increase incidence of neurodevelopmental disorders and influence cognitive abilities. Glucocorticoids are released in stress condition as endpoint activation of hypothalamus-pituitary-adrenal (HPA) axis. Evidence indicates a cross-talk between gut microbiota and brain function. This study assesses the effect of probiotic supplementation on behavioral functionand HPA axis action in stressed rats.Materials and Methods: The young rats born from dams exposed to noise stress (ST) during third trimester of pregnancy were used. Two groups of stressed animals were received a two-week probiotic supplementation before (pre-ST) and after (post-ST) birth. The time and distance to find hidden platform in Morris water maze were evaluated as spatial memory. Also entry to open arms in elevated plus-maze was considered as anxiety-like behaviors. The serum level of corticosterone was measured as the HPA axis function. Results: While the stressed rats decreased entries to open arms to one third compared to the controls (CON) the probiotic treatment increased the entries by two times. The ST rats required more time and distance to find the platform than did the CON animals. The pre- and post-ST rats significantly restored the impaired behavior almost near the CON ones. While the serum corticosterone concentration increased by 50% in the ST rats it was reduced to almost normal level in the pre- and post-ST rats. Conclusion: Our findings confirmed a link between the gut microbiome and probiotics with the behavioral functions and HPA axis. The probiotic treatment favorably affected the stress-dependent behavioral disorders and the interaction between HPA and gut-brain-microbiota axes.

Anxiety, Learning and memory, Microbiota, Probiotic, stress