RESUMO
Environmental exposure to agrochemicals during early stages of development can induce subtle alterations that could permanently affect normal physiology. Previously, we reported that in ovo exposure to atrazine (ATZ) disrupts testicular histoarchitecture in postnatal caimans (Caiman latirostris). To assess whether such alterations are the result of disruption of gonadal developmental programming, this study aimed to evaluate the expression of histofunctional biomarkers (VASA, ER, PR, PCNA, and aromatase) and genes involved in gonadal development and differentiation (amh, sox-9, sf-1 and cyp19-a1) in the gonads of male and female caiman embryos and to assess the effect of ATZ exposure on these biomarkers and genes in the gonads of male embryos. Our results suggest that amh, aromatase and sox-9 play a role in sex determination and gonadal differentiation. In male caiman embryos, ATZ exposure increased aromatase expression and altered the temporal expression pattern of amh and sox-9 evidencing an ATZ-induced disruption of gonadal developmental programming. Since the effects of ATZ are consistent across all vertebrate classes, the ATZ-mediated disruptive effects here observed could be present in other vertebrate species.
Assuntos
Jacarés e Crocodilos , Atrazina , Animais , Feminino , Masculino , Atrazina/metabolismo , Aromatase/metabolismo , Gônadas , TestículoRESUMO
Recently, we have described the ontogeny of histofunctional differentiation changes in the oviduct of Caiman latirostris. The expression of estrogen receptor alpha and progesterone receptor shows that the caiman oviduct could be a target of the action of xenoestrogens such as the widely environmentally present Bisphenol A (BPA), early in life. The aims of this study were: to complement oviduct characterization by establishing the ontogenetic changes in androgen receptor (AR) expression and assessing the effects of early postnatal exposure to 17-ß-estradiol (E2) or BPA on the histofunctional features of the oviduct. AR was expressed in all the stages studied. The spatial pattern of AR immunostaining changed from neonatal to juvenile caimans. In the luminal epithelium, changes were at the subcellular level, from cytoplasmic to nuclear. In the subepithelium, although both cytoplasmic and nuclear AR expression was observed, changes were mainly at tissue level, from the subepithelial compartment to the outer muscular layer. The oviduct was highly sensitive to E2 and BPA at the early postnatal developmental stage. E2- and BPA-exposed caimans showed increased luminal epithelial height and higher proliferative activity. Changes in histomorphological features (measured by a scoring system), steroid hormone receptors, collagen remodeling and muscle-associated proteins suggest a precocious oviduct histofunctional differentiation in E2- and BPA-exposed caimans. The modification of the temporal pattern of oviductal biomarkers suggests that organizational changes could impair C. latirostris reproductive health later in life. The alterations in the caiman female reproductive tract exposed to BPA highlight the importance of preserving aquatic environments from plastic pollution.
Assuntos
Jacarés e Crocodilos/metabolismo , Compostos Benzidrílicos/toxicidade , Genitália Feminina/metabolismo , Genitália Feminina/patologia , Fenóis/toxicidade , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Estradiol/farmacologia , Feminino , Proteínas Musculares/metabolismo , Oviductos/efeitos dos fármacos , Oviductos/metabolismo , Receptores Androgênicos/metabolismo , Receptores de Progesterona/metabolismo , Fatores de TempoRESUMO
Studies regarding the effects of endocrine-disrupting chemicals (EDCs) on the reproductive functions of wild animals have raised increasing concern. Thus, here we evaluated the consequences of in ovo exposure to endosulfan (END) and bisphenol A (BPA) in testes from neonatal to juvenile (Juv) caimans (Caiman latirostris). Caiman eggs were collected from areas with low to moderate anthropogenic intervention and incubated at male-producing temperature. At stage 20 of embryonic development (previous to gonad sex determination), eggs were exposed to either END (20 ppm) or BPA (1.4 ppm) and male gonad histomorphology examined in 10-day-old, 90-day-old, and Juv caimans. The relative seminiferous tubular area (RTA) was measured in testes and the proliferation index and the expression of estrogen receptor alpha (ERα) were quantified in intratubular cells. Regardless of the treatment, all eggs resulted in male hatchlings. The testes of EDC-exposed caimans presented tortuous seminiferous tubules with empty tubular lumens. The RTA of 10-day-old caimans exposed to BPA was decreased. The percentage of cells expressing ERα was not different after in ovo treatment with EDCs (compared to the Control group), although caimans exposed to END showed a different ERα distribution pattern. The proliferation index was lower in 90-day-old caimans exposed to END, and higher in Juv caimans exposed to BPA. In ovo exposure to END or BPA modified sensitive parameters of C. latirostris male gonads. The alterations described here might compromise not only the sexual maturation but also the reproductive performance of adult caimans. J. Exp. Zool. 325A:84-96, 2016. © 2015 Wiley Periodicals, Inc.