Tese
Efeitos de atrazina como desregulador endócrino na homeostase tecidual e nos perfis morfológico e esteroidogênico de testículos, dúctulos eferentes e próstata ventral de ratos adultos
Fecha
2017-09-28Autor
Elisângela Martins dos Santos
Institución
Resumen
Atrazine is a potent endocrine disruptor that affects testicular steroidogenesis, and
causes transient increase in testicular weight followed by atrophy, besides
reduction of 3β-HSD, decrease in testosterone and increase in estradiol levels,
being postulated that aromatase may be a target of atrazine. It is not known
whether the effects observed on the testis are reversible or permanent, nor
whether these effects are primary or secondary to changes in postesticular
segments, as the efferent ductules, what we aim to clarify in this study. For
comparison purposes, we also evaluated the ventral prostate. Adult male Wistar
rats receiving atrazine at the dosage of 200/mg/Kg for 7, 15, or 40 days were used.
Additionally, we evaluated if the effects of atrazine in these target organs could be
reversible after discontinuation of the exposure for a period of 75 days, period
longer than the spermatogenic cycle of rats (58 days). The exposure to atrazine
resulted in transient increased in testicular weight, luminal dilation, followed by
seminiferous tubule atrophy, as well as 3β-HSD reduction and increase in
aromatase in the Leydig cells. The testicular atrophy and 3β-HSD reduction were
more pronounced after the recovery period, in contrast with aromatase that
returned to control levels. Moreover, there was increase of 89%, 76%, and 42% in
macrophages subpopulations ED1-
/ED2+ resident, ED1+/ED2+ transitory and ED1+/
ED2- induced, respectively, which were positive for 3β-HSD, raising the possibility
of their involvement on steroidogenesis. The exposure to atrazine resulted in mild
effects on the ventral prostate, but remarkable morphological alterations on the
efferent ductules and disruption on tissue homeostasis, coincident with increase in
aromatase expression. These findings further emphasize that the testicular
damages caused by atrazine may be irreversible even after a recovery period
longer than the spermatogenic cycle, and suggest that at least part of the testicular
effects of atrazine may be secondary to the alterations in the efferent ductules.