Semester

Spring

Date of Graduation

2010

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Mitchell S. Finkel.

Abstract

Prenatal stress (PS) has been shown to exert profound effects on many organs in a variety of species. There is considerable evidence for sex-specific effects of prenatal stress. Our laboratory is the first to report effects of prenatal stress on myocardial function in male rats. The purpose of this study was to confirm our previous evidence of differences in myocardial function among prenatally stressed male and female rats and to explore possible mechanisms responsible for this difference. In this study, male and female Sprague-Dawley rats were subjected to prenatal stress (mother was stressed on day 14--21 of gestation) followed by restraint stress at weeks six and seven of postnatal age (PS+R). Following the second restraint, myocardial function was studied along with a proteomic analysis of the left ventricle. Male PS+R demonstrated both systolic and diastolic dysfunction compared to male Control +R, as evidenced by reduced systolic function (+dP/dt) (P<0.05), Left Ventricular Systolic Pressure (LVSP) (P<0.05), and diastolic function (--dP/dt) (P<0.05). There was no significant difference in systolic or diastolic function or left ventricular systolic pressure between female PS+R or female Control +R. There were no significant differences in Mean Arterial Pressure (MAP) or Heart Rate (HR) between PS+R rats of either sex. Proteomic analyses revealed selective up-regulation of 20 mitochondrial proteins and 5 additional stress-related proteins in male PS+R compared to male Control +R. The data also showed an up-regulation of 5 proteins and a down-regulation of 1 protein in female PS+R compared to female Control +R. These findings suggest a sex difference in the oxidative stress response to prenatal stress that may influence myocardial function. Further studies are needed to determine the roles that these differences play in the changes in myocardial function seen in male PS+R vs female PS+R.

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