Synergistic effects of early life mild adversity and chronic social defeat on rat brain microglia and cytokines

Publication date: Available online 21 December 2019Source: Physiology & BehaviorAuthor(s): Vasiliki Ferle, Anastasia Repouskou, George Aspiotis, Androniki Raftogianni, George Chrousos, Fotini Stylianopoulou, Antonios StamatakisAbstractExposure to early life stress affects the development and function of the brain and when followed by adversities in adulthood, the negative effects of stress are enhanced. Microglia has been proposed as a potential mediator of this phenomenon. In the present study, we investigated the long-term effects of mild early life stress, the consequences of a stressor in adulthood as well as their interaction on microglial and cytokine (PPARγ, IL-1β and TNFα) levels in the brain of adult male rats. As an early life stress we used a model of maternal neglect, in which the dam is present but non-accessible to the pup for 15min during postnatal days 10-13; as a stressor in adulthood we exposed animals to chronic social defeat (CSD) for 3 weeks. We determined in the hippocampus, prefrontal cortex and amygdala, the number of Iba-1+ microglial cells, the number of PPARγ+ cells as well as the relative expression of PPARγ, IL-1β and TNFα mRNA by qPCR. Following exposure to CSD, the number of Iba-1+ cells was increased in the hippocampus and the prefrontal cortex of adult animals exposed to mild early life stress, while in the absence of CSD no such difference was observed. Moreover, following CSD PPARγ levels were increased in the hippocampus of adult ma...

Source: Physiology and Behavior - December 21, 2019 Category: Physiology Source Type: research