Bisphenol A (BPA) is one of the environmental endocrine disrupting chemicals, which is present ubiquitously in daily life. Accumulating evidence indicates that exposure to BPA contributes to metabolic syndrome. In this study, we examined whether perinatal exposure to BPA predisposed offspring to fatty liver disease: the hepatic manifestation of metabolic syndrome. Wistar rats were exposed to 50 μg/kg per day BPA or corn oil throughout gestation and lactation by oral gavage. Offspring were fed a standard chow diet (SD) or a high-fat diet (HFD) after weaning. Effects of BPA were assessed by examination of hepatic morphology, biochemical analysis, and the hepatic expression of genes and/or proteins involved in lipogenesis, fatty acid oxidation, gluconeogenesis, insulin signaling, inflammation, and fibrosis. On a SD, the offspring of rats exposed to BPA exhibited moderate hepatic steatosis and altered expression of insulin signaling elements in the liver, but with normal liver function. On a HFD, the offspring of rats exposed to BPA showed a nonalcoholic steatohepatitis-like phenotype, characterized by extensive accumulation of lipids, large lipid droplets, profound ballooning degeneration, impaired liver function, increased inflammation, and even mild fibrosis in the liver. Perinatal exposure to BPA worsened the hepatic damage caused by the HFD in the rat offspring. The additive effects of BPA correlated with higher levels of hepatic oxidative stress. Collectively, exposure to BPA may be a new risk factor for the development of fatty liver disease and further studies should assess whether this finding is also relevant to the human population.
Jie Wei, Xia Sun, Yajie Chen, Yuanyuan Li, Liqiong Song, Zhao Zhou, Bing Xu, Yi Lin and Shunqing Xu
Liqiong Song, Wei Xia, Zhao Zhou, Yuanyuan Li, Yi Lin, Jie Wei, Zhengzheng Wei, Bing Xu, Jie Shen, Weiyong Li and Shunqing Xu
Phenolic estrogen pollutants, a class of typical endocrine-disrupting chemicals, have attracted public attention due to their estrogenic activities of imitating steroid hormone 17β-estradiol (E2) effects. Exposure to these pollutants may disrupt insulin secretion and be a risk factor for type 2 diabetes. In this study, we investigated the direct effects of phenolic estrogen diethylstilbestrol (DES), octylphenol (OP), nonylphenol (NP), and bisphenol A (BPA) on rat pancreatic islets in vitro, whose estrogenic activities were DES>NP>OP>BPA. Isolated β-cells were exposed to E2, DES, OP, NP, or BPA (0, 0.1, 0.5, 2.5, 25, and 250 μg/l) for 24 h. Parameters of insulin secretion, content, and morphology of β-cells were measured. In the glucose-stimulated insulin secretion test, E2 and DES increased insulin secretion in a dose-dependent manner in a 16.7 mM glucose condition. However, for BPA, NP, or OP with lower estrogenic activity, the relationship between the doses and insulin secretion was an inverted U-shape. Moreover, OP, NP, or BPA (25 μg/l) impaired mitochondrial function in β-cells and induced remarkable swelling of mitochondria with loss of distinct cristae structure within the membrane, which was accompanied by disruption of mRNA expression of genes playing a key role in β-cell function (Glut2 (Slc2a2), Gck, Pdx1, Hnf1 α, Rab27a, and Snap25), and mitochondrial function (Ucp2 and Ogdh). Therefore, these phenolic estrogens can disrupt islet morphology and β-cell function, and mitochondrial dysfunction is suggested to play an important role in the impairment of β-cell function.