ORF19-02 - Chronic Bisphenol A Exposure Alters Organ Weights and Vascular Reactivity in Adult Male Rats

Bisphenol A (BPA) is a commonly used chemical in the manufacturing of polycarbonate plastics and epoxy and vinyl ester resins. These plastic and resin materials are used in a variety of products including beverage bottles, food containers, the lining of metal food cans, thermal paper used for receipts, and numerous plastic medical devices. Humans are chronically exposed to low levels of BPA due to the leaching of BPA from these common materials. BPA is considered an endocrine-disruptor, though its health effects continue to be debated.

In order to mimic the nature in which humans are exposed to BPA, we developed a rodent model of chronic BPA exposure. Sprague Dawley male rats (10 weeks of age) were orally exposed to vehicle (DMSO), 1 mg BPA/kg, or 10 mg BPA/kg, 5 days per week for 16 weeks. At the end of the study, various organ weights were measured and vascular reactivity of mesenteric resistance arterioles was evaluated.

Heart, left ventricle, and adrenal weights were significantly increased in both BPA treatment groups (heart weight in g/kg body weight, vehicle: 2.7258±0.0248, 1 mg/kg BPA: 2.9732±0.0655, 10 mg/kg BPA: 2.8806±0.0407, p< 0.05)(left ventricle weight in g/kg body weight, vehicle: 2.2016±0.0223, 1 mg/kg BPA: 2.3965±0.0486, 10 mg/kg BPA: 2.3249±0.0391, p< 0.05)(adrenal weight in g/kg body weight, vehicle: 0.0949±0.0011, 1 mg/kg BPA: 0.1134±0.0055, 10 mg/kg BPA: 0.1080±0.0034, p< 0.05). Additionally, liver and kidney weights were significantly increased in the 10 mg/kg BPA treatment group (liver in g/kg body weight, vehicle: 36.3129±0.5290, 10 mg/kg BPA: 37.8724±0.3720, p< 0.05)(kidney weight in g/kg body weight, vehicle: 6.1440±0.0454, 10 mg/kg BPA: 6.5720±0.1427, p< 0.05). There were minor differences in the phenylephrine contractions and acetylcholine-induced relaxations in mesenteric arterioles from both BPA treatment groups. However, in the presence of L-NAME, there was a significant increase in acetylcholine-induced relaxations in mesenteric arterioles from both BPA treatment groups.

These data indicate that chronic BPA exposure affects numerous organ systems and alters vasodilatory pathways in the vasculature. Future studies will determine if BPA exposure alters corticosteroid synthesis and if the cardiovascular pathophysiology observed results in alterations in blood pressure regulation.