RESUMO
La exposición perinatal a diversos contaminantes ambientales y a otros agentes químicos afecta en formairreversible la diferenciación y programación de diversos tipos celulares, alterando cualitativa y cuantitativamentesus receptores hormonales mediante el mecanismo del imprinting, afectando su función y determinando el desarrollo de diversas patologías más tarde en la vida. En el presente trabajo se describen los agentes más conspicuos que actúan por este mecanismo afectando de por vida la salud reproductiva y la sexualidad. La investigación de este mecanismo, la identificación de sus agentes inductores y el desarrollo de medidas legislativas y administrativas para minimizar el daño constituyen un desafío pendiente para mejorar la saludreproductiva de las futuras generaciones.
Perinatal exposure to various environmental pollutants and other chemical agents irreversibly affects thedifferentiation and programming of various cell-types. This process quantitatively and qualitatively alters their hormone receptors through the mechanism of imprinting, affecting their function and determining the development of various pathologies later in life. The present report describes the most conspicuous agents acting through this mechanism, affecting for life reproductive health and sexuality. The study in detail of this mechanism, the identification of imprinting-inducing agents and the development of legislative and administrative measures to minimize damage constitute a pending challenge to improve future generations reproductive health.
Assuntos
Humanos , Masculino , Feminino , Gravidez , Poluentes Ambientais/efeitos adversos , Poluentes Ambientais/toxicidade , Efeitos Tardios da Exposição Pré-Natal , Reprodução , Bifenilos Policlorados/efeitos adversos , Cádmio/efeitos adversos , Cafeína/efeitos adversos , Dióxido de Nitrogênio/efeitos adversos , Etanol/efeitos adversos , Praguicidas/efeitos adversos , Chumbo/efeitos adversos , Poluição por Fumaça de TabacoRESUMO
Lead is a widely spread environmental pollutant known to affect both male and female reproductive systems in humans and in experimental animals. The present study investigated the effect of a chronic exposure to lead on different parameters of estrogen stimulation in the uteri of prepubertal rats. Chronic exposure to lead enhanced some parameters of estrogen stimulation, inhibited other estrogenic responses, while the remainder were unaltered. Estrogen-induced uterine eosinophilia (24 h), the proportion of uterine eosinophils in the mesometrium (6 h), and luminal epithelial hypertrophy and RNA content (24 h) appeared to be enhanced by lead exposure, compared to lead-unexposed control animals. Eosinophilia in the endometrium (6 h), the proportion of uterine eosinophils in the endometrium (6 and 24 h), edema in superficial and deep endometria (6 h), luminal epithelial hypertrophy (6 h), and mitotic response (cell proliferation) in all uterine cell types were inhibited by lead exposure, whereas circular myometrial hypertrophy was not significantly modified. The effects of lead exposure on responses to estrogen found in this study showed some differences with those previously reported for acute or subacute exposure to lead. The results revealed an interaction with the different mechanisms of estrogen action in the uterus at various levels, suggesting that some uterine cell types are more sensitive to lead than others. The relevance of the results for lead-induced infertility is discussed in this article, and possible mechanisms of action are proposed.
