Chronic exposure to bisphenol S impairs hepatic mitochondrial dynamics, induces endoplasmic reticulum stress, and worsens metabolism in high-fat diet fed mice

Abstract

Obesity triggers numerous other disorders, such as type 2 diabetes mellitus, dyslipidemia, and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD). Endocrine Disrupting Chemicals (EDC) such as Bisphenol A (BPA) have obesogenic effects, which have been replaced by Bisphenol S (BPS). The chronicity of obesity and MASLD, as well as BPS exposure, compromises Mitochondrial Biogenesis (MBG) and triggers the endoplasmic reticulum (ER) stress. Therefore, this study aims to investigate whether BPS exposure affects hepatic morphology, MBG, and ER stress pathways in the liver in male mice fed a standard and high-fat diet. C57BL/6 adult male mice were fed a control (SC) or high fat (HF) diet for 12 weeks and exposed or not to BPS (25 μg/kg of body mass/day) by drinking water. The animals were divided into a control diet not exposed to BPS (SCD), a control diet exposed to BPS (SCDB), a high-fat diet not exposed to BPS (HFD), and a high-fat diet exposed to BPS (HFDB) for 12 weeks. Body mass, glucose, and lipid profile were evaluated. In the liver, morphology and lipid metabolism, ER stress, and MBG markers were assessed. Data were presented as mean ± standard deviation and analyzed by one-way ANOVA, followed by the Holm-Sidak post-test. p < 0.05 was considered significant. BPS exposure led to increased body mass, and disrupted lipid and glucose metabolism, leading to alterations in hepatic mitochondrial dynamics, ER stress, and compromised hepatic structural support. The combination with a high-fat diet augmented insulin levels disrupted cholesterol metabolism, and compromised mitochondrial and endoplasmic reticulum homeostasis, resulting in more severe structural damage. In conclusion, BPS was able to facilitate the development of obesity and increase the risk of manifesting associated comorbidities when combined with a high-fat diet.

Keywords: Bisphenol S; Endoplasmic reticulum stress; High-fat diet; Metabolic dysfunction-associated steatotic liver disease; Mitochondrial biogenesis.