Resiliency of prenatally stressed male and female rats following chronic mild stress exposure

Daniela Schnitzler, Ying Sze, Paula Brunton

Research output: Contribution to conferencePosterpeer-review

Abstract

Introduction: Repeated social stress experienced by pregnant dams ‘programs’ long-term changes in the offspring’s brain and behaviour, including hypothalamo-pituitary-adrenal (HPA) axis dysregulation in both sexes and increased anxiety-like behaviour in the male offspring (1). This ‘programming’ may prepare the offspring for a suboptimal postnatal environment. However, a ‘mismatch’ between the predicted and actual postnatal environment may result in maladaptation. Here we aimed to test the resiliency of prenatally stressed (PNS) rats by investigating the impact of chronic stress in adulthood on anxiety-like behaviour and HPA axis activity. Methods: To generate PNS offspring, pregnant dams were exposed to social stress (modified resident-intruder paradigm; 10 min/day) on gestational days 16-20. Control dams remained undisturbed. At 9-11 weeks of age, the male and female control and PNS offspring were either exposed to 7 days of chronic variable stress (CS) or undisturbed (no chronic stress; nCS). On the 8th day, anxiety-like behaviour was assessed using the light-dark box (LDB). Immediately afterwards, rats were killed, and trunk blood was collected. Plasma corticosterone concentrations were determined by radioimmunoassay. Statistics: A two- or three-way ANOVA was used with Student-Newman-Keuls post-hoc tests. To compare two groups a Student’s T-test was used. P<0.05 was considered statistically significant. Results: As expected, PNS males showed more anxiety-like behaviour compared to control males, with no differences between control and PNS females. However, both CS PNS males and females displayed significantly less anxiety-like behaviour compared to their respective controls. Despite the similarity in behaviour, corticosterone responses were sexually dimorphic. After LDB exposure, plasma corticosterone concentrations were significantly greater in the CS PNS males compared to nCS PNS males, with no significant differences between the CS and nCS control males. In contrast, circulating corticosterone was significantly lower in the PNS females compared to the control females, regardless of chronic stress exposure. Conclusion: The results support the ‘maladaptive hypothesis’ theory, in which PNS confers a degree of resiliency during chronic stress exposure in adulthood. In addition, chronic stress exposure abolishes the sex differences observed in anxiety-like behaviour induced by PNS. 1. Brunton, P.J., Russell, J.A., 2010. J Neuroendocrinol 22, 258–271.
Original languageEnglish
Publication statusUnpublished - 2019
EventBritish Neuroscience Association Festival of Neuroscience 2019 - Dublin, Ireland
Duration: 14 Apr 201917 Apr 2019
http://meetings.bna.org.uk/bna2019/

Conference

ConferenceBritish Neuroscience Association Festival of Neuroscience 2019
Country/TerritoryIreland
CityDublin
Period14/04/1917/04/19
Internet address

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