Microglia are necessary for probiotics supplementation to improve impaired fear extinction caused by pregnancy stress in adult offspring of rats

The prevention and treatment of fear-related disorders in offspring affected by pregnancy stress remains challenging at clinic. Here, we examined the effects of gut microbiota of stressed pregnant rats on the fear extinction of their offsprings, and the potential mechanisms. We found that gut microbiota transplantation from rats with pregnancy stress to normal pregnant rats impaired fear extinction, induced microglial activation and synaptic phagocytosis, increased synapse loss in offsprings. Probiotics supplement during pregnancy stress partly normalized pregnancy stress-induced gut microbiota dysbiosis of pregnant rats, and promoted fear memory extinction, inhibited fear memory reappearance, and limited microglial activation and synaptic phagocytosis in offsprings. These data revealed that gut microbiota of stressed pregnant mother improved the development of fear-related disorders of offspring, which may be associated with microglial synaptic pruning.