Bisphenol a linked to chromosome damage in Mice.

Hunt PA, Koehler KE, Susiarjo M, Hodges CA, Ilagan A, Voigt RC, et al. 2003. Bisphenol A exposure causes meiotic aneuploidy in the female mouse. Curr Biol 13:546-553.

Bisphenol A (BPA) is a common component in polycarbonate plastics used in food and beverage packaging and in dental sealants. BPA has hormone-like properties that mimic the effects of endogenous estrogens. Although a variety of reproductive complications have been ascribed to compounds with androgenic or estrogenic properties, little attention has been directed to the potential consequences of such exposures to the genetic quality of the gamete.

During a 1998 study on meiosis in mouse oocytes, NIEHS grantee Patricia A. Hunt of the Department of Genetics at Case Western Reserve University and colleagues observed a spike in meiotic disturbances including aneuploidy (an abnormal number of chromosomes). The spike coincided with the test mice having been accidentally exposed to BPA following the use of a harsh detergent to clean their plastic cages. This observation prompted Hunt and colleagues to replicate the finding in a controlled experiment. The results implicate BPA as a potent disruptor of meiosis and provide the first conclusive link between mammalian aneuploidy and an accidental environmental exposure to BPA.

The researchers dosed mice with environmentally relevant doses of BPA. Eggs from the dosed animals showed dose-dependent increases in problems of meiosis including aneuploidy and disorganized or unaligned chromosomes. Hunt and colleagues found that only brief exposure to relatively modest concentrations of BPA was necessary to induce significant meiotic effects. The study suggests that the mouse oocyte may provide a sensitive system for the study of reproductive toxicants.

The kinds of chromosomal abnormalities resulting from both the accidental exposure and the controlled experiment are leading causes of miscarriage, congenital birth defects, and mental retardation in humans. Further study is necessary before direct conclusions can be drawn on potential human health effects from BPA. However, the current results raise concerns, especially when considered alongside those of a study by Schonfelder et al., published in the March-April 2002 issue of Neoplasia, indicating that pregnant women are exposed to comparable amounts of BPA.