Generational effects of chronic stress

Abstract

Traumatic events that affect behavior in the current generation may also impact future generations. Although the effects of stress on pregnant mothers have been extensively explored, we know little about how trauma prior to conception affects offspring conceived afterwards. Here we demonstrate that chronic predator stress in adult mice alters behavior, as well as the first filial (F1) generation. Adult F0 mice were chronically exposed to a predator rat or control condition and assessed for anxiety-like (EPM, OFT, LDB) and social (SIT) behaviours. F0 mice were also assessed on circadian locomotor activity patterns prior to and following predator exposure or control conditions. F0 predator stressed mice froze more than F0 control mice overall and each day of the chronic exposure. In addition, F0 predator stressed mice exhibited increased anxiety-like behaviours (ALB) on the EPM relative to F0 controls. Following behavioral testing, F0 mice were group matched and bred to generate the F1s. Anxiety-like and social behaviors were assessed in the F1s during adolescence and again, following a mild stressor, in adulthood. Circadian locomotor activity was also monitored in the F1 adults. Adolescent offspring from predator stressed parents (PSO) exhibited increased ALB on the EPM compared to offspring of controls (CO). However, in adulthood, following the mild stressor, PSO mice showed decreased ALB compared to CO mice, suggesting increased resilience. These findings indicate that chronic pre-conception predator stress results in lasting effects on future generations, an outcome that may lead to improved understanding of the etiology of anxiety and stress-related pathologies.