O estresse precoce altera a susceptibilidade aos efeitos da hipóxia-isquêmica pré-natal: alterações comportamentais e hormonais durante a juventude de ratos Wistar machos e fêmeas

Abstract

Environmental stress in the prenatal or neonatal period can be precursors of pathologies of a physiological, behavioral and/or psychological nature, leading to the tendency of individuals towards affection disorders, such as anxiety and depression. In the present study, we subjected male and female rats to two types of stress: hypoxia-ischemic (HI) and maternal separation (SM) and, through these, we were able to mimic pre- and postnatal stress, respectively. In addition, we combined perinatal double stresses (DEP). The aim of the present study was to evaluate the effects of HI and MS, alone and in combination, on body weight, hormone release, and anxiety-like and depressive-like behavior. On the eighteenth (E18) gestational day, pregnant Wistar females were randomly divided into control (CN), surgical control (SHAM) and hypoxia-ischemic (HI) groups. Females in the HI group had their uterine horns exposed and their uterine arteries clamped for 45 minutes. In the SHAM group, the females underwent the same type of surgery, except for the clamping of the uterine horns. After the term birth of the pups, the litters of the three groups were subdivided into not separated (NS) and maternal separation (SM). The maternal separation protocol occurred from the first (P1) to the fifteenth postnatal day (P15), for 180 minutes. At P30, the animals were separated by sex, totalizing 12 groups. In the same period, the experimental animals were submitted to the elevated plus maze behavioral tests and the open field test, to evaluate the anxious-like behavior, to the sucrose preference test and to the forced swimming test to evaluate the anxiety-like behavior. depressive. After the tests, we evaluated the amount of serum corticosterone. HI, SM and DEP significantly decreased the animals' body weight. In addition, early stress led the animals to develop anxiety-like and depressive-like behavior, however, we did not observe hormonal dysfunctions. Our findings suggest that early stress produces behavioral changes in animals, but further studies are needed to better elucidate these issues.