IDENTIFICATION OF ENDOCRINE DISRUPTORS USING AN ORGANOTYPIC VAGINAL TISSUE MODEL.

Environmental or occupational exposure to a broad variety of chemical agents can alter normal endocrine function. The effects of these “endocrine disruptors” (ED) can have serious health implications including deleterious effects to reproductive capacity, fetal development, the immune system, and carcinogenesis. Current animal tests are expensive, use a large number of animals, and are not necessarily applicable to humans.  In addition, the Cosmetics Directive bans the use of animals for studies involving a broad variety of cosmetic and personal care products.  In this study, we investigated the potential use of an organotypic tissue model, EpiVaginalTM, for Tier 1 screening of chemicals that may be agonists or antagonists of the estrogen receptor (ER).  MTT, H&E staining, RT-PCR, and ELISA assays were used to define tissue viability, structure, gene expression, and estrone release patterns, respectively.  Based on the MTT studies, only concentrations resulting in >50% tissue viability were used. H&E stained tissue cross-sections showed thinning of the basal and parabasal layers following 72 hour exposure to ER antagonists when compared to the control tissues; exposure to ER agonists resulted in thicker basal and parabasal layers, indicating stimulation of cellular proliferation.  RT PCR analysis showed an increase in progesterone receptor B (PRb) levels for 3 of 3 agonists and a decrease or no change for 6 of 8 antagonists when compared to negative controls.  Furthermore, ER-α expression increased following exposure to the ER agonists and decreased following exposure to ER antagonists.  ELISA assays showed increased estrone release by ER agonists but not ER antagonists.  Based on estrone release (n=22 test articles), a prediction model (PM) for ER agonists was established. The PM identifies ER agonists with a high sensitivity (85.7%), specificity (100%), and accuracy (95.5%).  In conclusion, the EpiVaginal tissue appears to be a useful in vitro model to screen for chemicals with endocrine disrupting potential.

Endocrine disruptors, Endocrine function, EpiVaginal, ER agonist, ER Antagonist, Estradiol receptor, Estrogen receptor, Estrogen receptor agonists, Progesterone receptor, TEER, Tissue stratification, Tissue thickness, VEC-100, VEC-100-FT

17-α ethinyl estradiol, 17-β estradiol, 4-Hydroxytamoxifen , 6-Hydroxychromene-3-carboxaldehyde, Acenaphthylene, Anthracene , Auronofin, Benzophenone-3, Cadmium, Danazol, Equilenin, Equilin, fluorathene, Flutamide, Isobutyl 4-hydroxybenzoate, Mestranol, Methomyl, Phenanthrene, p-Nonylphenol, Raloxifene-HCl, Trifluorpenazine