Oral homeostasis disruption by medical plasticizer component bisphenol A in adult male rats.

OBJECTIVES/HYPOTHESIS Bisphenol A (BPA) is a synthetic estrogen-like chemical mimetic widely used in the manufacture of polycarbonate plastics and epoxy resins found in numerous consumer products including food packaging, medical devices, and dental sealants. Because it is recovered in fluids and it can reach high levels in saliva, this study aimed to evaluate its safety on oral homeostasis by examining its effects on salivary glands, mouth epithelium, water consumption, and salt preference, each parameter being estrogen sensitive. STUDY DESIGN Randomized controlled trial involving rats. METHODS A dose-response study was conducted in adult Wistar rats randomized into five groups (n = 12). BPA was administered over 6 weeks via drinking water to obtain daily dose exposures of 0 μg/kg, 5 μg/kg, 50 μg/kg, 5 mg/kg, and 12.5 mg/kg of body weight. To evaluate salt preference, 1% NaCl solution and pure water intakes were measured for 3 days by offering two-bottle choices. The rats were then killed; oral biopsies were done and submandibular glands were removed for histologic and morphometric analysis. RESULTS According to the dose-response curve, BPA decreased total drinking but increased salt preference, which was inversely proportional to water consumption (Kruskal-Wallis, P < .01). It also causes oral dryness and histologic changes in the acinar structures of the submandibular glands at the lowest doses (Kruskal-Wallis, P < .01). CONCLUSIONS This study shows that oral exposure to BPA in the rat disrupts thirst and buccal homeostasis and raises questions about the salivary gland secretions.