Early postnatal exposure to xenoestrogens alters the expression of molecules involved in the postnatal differentiation of the oviduct of the broad-snouted caiman (Caiman latirostris)

MORA, S.C.; GALOPPO, G.H.; MUÑOZ-DE-TORO, M.; TAVALIERI, Y.E.; LUQUE, E.H.

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencias; 2019

Sociedad Argentina de Biología (SAB)

The broad-snouted caiman (Caiman latirostris) is a crocodilian species that inhabits South American wetlands. In this species, the differentiation of the female reproductive tract (oviduct) is completed postnatally and is characterized by temporal-spatial patterns of histofunctional changes. Recently, we have shown that the exposure to Bisphenol A (BPA) or 17β-Estradiol (E2) at critical stages of embryo development affects oviduct postnatal differentiation, leading to a precocious adenogenesis. Adenogenesis is regulated by the Wnt signaling pathway in many vertebrate species. The aim of this study was to determine the molecular mechanism behind altered adenogenesis. We established the ontogeny and evaluated the effects of postnatal exposure to BPA or E2 on the expression of molecules of the Wnt signaling pathway such as Wnt-7a, Wnt-5a, β-catenin and FoxA2. Archived paraffin-embedded samples from intact caimans were used to establish ontogenies. To assess the effect of xenoestrogens, early postnatal caimans were treated with E2 (0.014 or 1.4 ppm) or BPA (1.4 or 140 ppm), and sacrificed 7 days after last injection. Protein expression was assessed by IHC and quantified by image analysis. ANOVA or Kruskal-Wallis was performed to obtain the overall significance, followed by Dunnett?s or Dunn?s as post hoc-test, respectively. P < 0.05 was accepted as significant. Early postnatal oviducts were highly sensitive to E2 and BPA evidenced not only by increased histofunctional score but by decreased α-SMA/desmin ratio. The exposure to xenoestrogens deregulates the expression pattern of Wnt-7a, Wnt-5a, β-catenin and FoxA2. These molecules must be expressed at the right time and the right place in order to warrant a correct differentiation process, thus any alteration in their expression patterns may impair the reproductive health of C. latirostris later in life.