Bisphenol A Exposure Induces Small Intestine Damage Through Oxidative Stress, Inflammation, and Microbiota Alteration in Rats

Bisphenol A (BPA), a widespread environmental contaminant used in plastics and resins, poses significant health risks due to its endocrine-disrupting properties and potential for inducing intestinal toxicity. This study explored the toxicological effects of BPA on the small intestine of rats, focusing on the duodenum, jejunum, and ileum. Histopathological evaluation revealed that the duodenum experienced the most severe structural damage, including villous atrophy, epithelial shedding, and mitochondrial degeneration. BPA exposure disrupted oxidative stress homeostasis by reducing superoxide dismutase activity and increasing malondialdehyde levels, along with upregulating antioxidant-related genes like <i>GPX2</i> and <i>HO-1</i> upregulated, indicating lipid peroxidation and oxidative damage. Inflammatory markers such as <i>IL-1</i> and <i>NFκB</i> were significantly upregulated, highlighting an active inflammatory response and epithelial cell apoptosis. BPA also altered lipid metabolism, with increased expression of lipogenic genes such as <i>SREBP-1c</i> and <i>FAS</i>, indicating metabolic dysregulation. Fecal microbiota analysis revealed reduced α-diversity, enrichment of pathogenic taxa like <i>Escherichia-Shigella</i>, and depletion of beneficial genera such as <i>Lachnospiraceae NK4A136 group</i>, exacerbating gut inflammation and barrier dysfunction. These findings suggest that BPA-induced small intestinal damage is driven by oxidative stress, inflammation, and gut dysbiosis, with the duodenum and jejunum being the more vulnerable segments.