Theses and Dissertations from DePaul University

Date of Award

Spring 2026

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Science

College

College of Science and Health

First Advisor

Margaret Bell

Abstract

Per- and polyfluoroalkyl substances (PFAS) are a class of widespread persistent organic pollutants associated with metabolic and neural dysfunction in humans. These processes are also affected by Western diet high sugar high fat contents. However, interacting effects of PFAS exposure and Western diet on metabolic regulation and feeding behavior have not been tested. Exposure to PFAS is high during sensitive gestational and neonatal periods of development. Adolescence is a key period where nutritional demands shift, eating habits are established, and gonadal hormones change. This study tests the hypothesis that early life exposure to PFOS alters adolescent metabolic function and feeding behavior in ways that are influenced by a Western diet with sex-specific effects for each outcome.   To test this, ten pregnant Sprague Dawley rats were fed perfluorooctane sulfonic acid (PFOS, 0.5 mg/kg dam BW) or vehicle control (0.5% Tween-80 in water) daily over gestation and lactation. Starting a week after weaning, on postnatal day 28 (P28), two male and two female pups from each litter received either standard chow food pellets or a Western diet plus chow ad libitum until euthanasia at the end of adolescence (P56). The Western diet consisted of a three-day rotating menu that contained different popular chips, cake, meat, and candy administered daily. Effects of PFOS exposure, diet, and sex were determined with two and three-way analysis of variance.   Sweet preference, measured as percent intake of sucrose water, was lower in Western diet exposed females (F(1,33)=5.1, p=0.03), but not males, compared to chow controls, with no statistically significant effects of PFOS. Fat preference, measured in a similar test with high-fat pellets, was reduced by PFOS exposure in males (F(1,35)=5.6, p=0.02), but not females, without significant effects of Western diet. Fasted blood glucose (F(1,68)=45, p< 0.01) was greater in both sexes on a Western diet, with no statistical effect of PFOS. However, PFOS exposed animals showed delays in blood glucose concentrations to return to baseline, with higher concentrations at 120 minutes. In females, this was additive to dietary effects (F(1,33)=6.6, p=0.01,) while in males, Western diet could not further increase concentrations beyond that already caused by PFOS exposure (F(1,35)=8.3, p< 0.01).   Taken together, these results affirm effects of PFOS exposure on dysregulated glucose metabolism and raise behavioral effects as possible indicators of PFOS effects on lipid homeostasis and/or as a mechanism towards metabolic syndrome. Moreover, they highlight the importance of testing effects of chemical contaminants in a range of homeostatic states, as two-hits over development can better model the human condition and reveal otherwise latent effects.

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