Citation:

Woolard, E., C. Miller, Kathy Mcdaniel, T. Beasley, W. Oshiro, AND V. Moser. Can Molecular Hippocampal Alterations Explain Behavioral Differences in Prenatally Stressed Rats? Experimental Biology, Chicago, IL, April 22 - 26, 2017.

Impact/Purpose:

Abstract for poster presentation at Experimental Biology 2017 Meeting

Description:

Studies in both humans and animals have shown that prenatal stress can alter cognitive function and other neurological behaviors in adult offspring. One possible underlying mechanism for this may lie with alterations in hippocampal gene expression. The present study examined genotypical outcomes in adult male and female offspring of rats exposed to variable stress during pregnancy. Dams (n=15/treatment) were subjected to several non-chemical stressors including intermittent noise, light, crowding, restraint, and altered circadian lighting, from gestational day (GD) 13 to 20. Tail blood was drawn on GD 12, 16 and 20 to verify a stress response. Corticosterone levels were not different between the stressed and non-stressed dams on GD12 but was significantly increased in stressed dams on GD 16 and 20 compared to controls. Dams gave birth on GD22 (postnatal day or PND 0). Several behavioral tests were used to assess the cognitive and behavioral phenotype of the offspring from PND 49 through 86, including the Morris water maze and novel object recognition. Male and female stressed offspring showed reduced reversal learning on the Morris water maze and stressed females did not show a significant preference for the novel object (57 ± 8%) while control females did (71 ± 3%). This indicates altered cognition in prenatally stressed offspring. On PND 91-92, offspring were necropsied and hippocampal tissue was collected. Genotypic outcomes of prenatal stress were assessed by quantifying hippocampal mRNA expression of five select genes thought to be implicated in these behaviors. The select genes were Brain-Derived Neurotrophic Factor (Bdnf), Tropomyosin Receptor Kinase 2 (Trk2), DNA Methyltransferase (Dnmt) 1, Dnmt3a, and Dnmt3b, with Hypoxanthine Guanine Phosphoribosyltransferase (Hprt) used as an endogenous control. mRNA expression showed a significant difference in Dnmt3b levels between control and prenatally stressed female offspring (p=0.02). A trend with female offspring Dnmt3a levels suggested additional alterations in basal levels of hippocampal mRNA expression (p=0.06). These preliminary findings support a role for hippocampal gene expression in long-term changes in offspring of prenatally stressed dams.This is an abstract of a proposed presentation and does not reflect US EPA policy.

Record Details: