Oral exposure to low dose bisphenol A aggravates allergic airway inflammation in mice

Bisphenol A (BPA) is widely used in many consumer products and has adverse effects on human health including allergic diseases. We investigated the effects of low dose BPA, comparable to actual human oral exposure, on allergic asthma in mice. C3H/HeJ male mice were fed a chow diet containing BPA (equivalent to 0.09, 0.90, or 9.01 mu g/kg/day) and were intratracheally administered ovalbumin (OVA, 1 mu g/animal) every two weeks from 5-11 weeks of age. All doses of BPA plus OVA enhanced pulmonary inflammation and airway hyperresponsiveness, and increased lung mRNA levels of Th2 cytokine/chemokine, and serum OVA-specific IgE and IgG(1) compared to OVA alone, with greater effects observed in the middle- and high-dose BPA plus OVA groups. Furthermore, high-dose BPA with OVA decreased lung mRNA levels of ER.j3 and AR compared with OVA. Furthermore, BPA enhanced OVA-restimulated cell proliferation and protein levels of IL-4 and IL-5 in mediastinal lymph node (MLN) cells in OVA-sensitized mice. In bone marrow (BM) cells, middle-dose BPA with OVA increased Gr-1 expression. In conclusion, oral exposure to low-dose BPA at levels equivalent to human exposure can aggravate allergic asthmatic responses through enhancement of Th2-skewed responses, lung hormone receptor downregulation, and MLN and BM microenvironment change.