Estrogen and bisphenol A affect male rat enamel formation and promote ameloblast proliferation

Endocrinology. 2014 Sep;155(9):3365-75. doi: 10.1210/en.2013-2161. Epub 2014 Jul 8.

Abstract

Bisphenol A (BPA) is a widespread endocrine disrupting chemical (EDC) strongly suspected to have adverse health effects. Numerous tissues and cells are affected by BPA, and we showed recently that BPA targets include ameloblasts and enamel. We therefore investigated the effects of BPA on ameloblasts and the possible involvement of the estrogen signaling pathway. Rats were exposed daily to low-dose BPA, and developed enamel hypomineralization similar to human molar incisor hypomineralization (MIH). BPA increased ameloblast proliferation in vivo and in vitro. The proliferation of the rat dental epithelial cell line HAT-7 was also increased by estrogen (E2). Ameloblasts express ERα but not ERβ both in vivo and in vitro. The ER antagonist ICI 182,780 was used to inactivate ERα and abolished the effects of E2 on cell proliferation and transcription, but only partially reduced the effects of BPA. In conclusion, we show, for the first time, that: 1) BPA has ER-dependent and ER-independent effects on ameloblast proliferation and gene transcription; 2) the estrogen signaling pathway is involved in tooth development and the enamel mineralization process; and 3) BPA impacts preferentially amelogenesis in male rats. These results are consistent with the steroid hormones having effect on ameloblasts, raising the issues of the hormonal influence on amelogenesis and possible differences in enamel quality between sexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ameloblasts / cytology
  • Ameloblasts / drug effects*
  • Ameloblasts / metabolism
  • Amelogenesis / drug effects
  • Animals
  • Benzhydryl Compounds / pharmacology*
  • Cell Proliferation / drug effects*
  • Dental Enamel / cytology
  • Dental Enamel / drug effects*
  • Dental Enamel / metabolism
  • Endocrine Disruptors / pharmacology*
  • Estrogen Receptor alpha / genetics
  • Estrogen Receptor alpha / metabolism
  • Estrogen Receptor beta / genetics
  • Estrogen Receptor beta / metabolism
  • Estrogens / pharmacology*
  • Male
  • Phenols / pharmacology*
  • Rats
  • Rats, Wistar

Substances

  • Benzhydryl Compounds
  • Endocrine Disruptors
  • Estrogen Receptor alpha
  • Estrogen Receptor beta
  • Estrogens
  • Phenols
  • bisphenol A