Investigating the effect of parental pre-gestational stress on ethological parameters in male rat offspring

Abstract

Although extensive research has focused on the impact of maternal stress during pregnancy, there remains a significant gap in understanding the influence of pre-pregnancy stress experienced by each parent on the behavioral outcomes of their offspring. In this study, 36 adult rats were divided into control and stress groups. In stress groups, female and male rats were subjected to predatory stress (exposed to cat twice a day, 1 hour per session) for 15 and 50 consecutive days, respectively. After the stress procedure, the stressed and control rats were mated to create four groups of breeding pairs: control male/control female, stressed female/control male, control female/stressed male, and stressed male/stressed female. On post-natal days 30-31, the offspring underwent testing on elevated plus maze (EPM) for evaluating fear and exploratory behaviors, and blood samples were taken to measure their plasma corticosterone concentration. Before EPM test, half of the pups of each group were exposed to acute predatory stress. The results indicated that the disparity in corticosterone levels, fear, and exploratory behaviors between acute stressed offspring and their non-acute stressed counterparts was more pronounced in groups with maternal or paternal stress, whereas the difference was minimal in control groups. The combined effect of maternal and paternal stressors produced non-additive effects on corticosterone and behavioral responses. These findings suggest that pre-gestational stress can exacerbate the effect of acute stress on offspring ethological parameters and exposure to stressful conditions prior to pregnancy can exert important effects on physiology and behavior of the offspring later in life.