Environmental contaminant BPA causes intestinal damage by disrupting cellular repair and injury homeostasis in vivo and in vitro

Abstract

Our previous studies have shown that the environmental contaminant bisphenol A (BPA) exhibits strong intestinal toxicity and can readily cause intestinal barrier dysfunction. However, the causal relationship between adverse biological processes of BPA-induced intestinal tissue and the role of key signaling molecules in it requires further investigation. In this study, we established a mouse and intestinal epithelial cell model of BPA treatment to determine the underlying molecular mechanisms of BPA-induced intestinal injury. The results showed that the BPA treatment increased the intestinal permeability and disrupted the barrier function by increasing the chemical marker content and tight junction expression in intestinal tissues and blood circulation. BPA also altered the oxidative and antioxidant status of intestinal epithelial cells by increasing ROS and RNS contents and decreasing the activity levels of SOD, GPx, CAT, and T-AOC. BPA further induced inflammatory responses by upregulating the gene abundance of key factors of the innate immune system (TLR2, TLR4, MyD88, and NF-κB), the transcriptional activity of NF-kB, and the secretion of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α). Moreover, apoptosis was activated by BPA, whereas cell proliferation was inhibited by BPA. Mechanistically, co-treatment of intestinal epithelial cells with BPA using the oxidative stress scavenger NAC, the NF-κB-specific inhibitor JSH-23, and the apoptosis inhibitor Z-VAD-FMK, respectively, showed that BPA activates the innate immune response by inducing oxidative stress. Consequently, apoptosis is promoted, and cell proliferation is inhibited, ultimately disrupting the intestinal barrier function. Our findings provide insight into the pathogenesis of BPA-induced gut injury.