RESUMO
This study investigated whether or not prepubertal exposure to the fish contaminants methylmercury (MeHg) and the polychlorinated bisphenol Aroclor in low doses interferes with the histomorphometry of the testes, epididymis, liver and kidneys in rats. Wistar male rats, 21 days old, were allocated into the following: control (n = 17, received corn oil), MeHg (n = 17, received MeHg at 0.5 mg/kg/day), Aroclor (n = 17, received Aroclor at 1.0 mg/kg/day), low mix (n = 18, received MeHg at 0.05 mg/kg/day and Aroclor at 0.1 mg/kg/day), high mix (n = 18, received MeHg at 0.5 mg/kg/day and Aroclor at 1.0 mg/kg/day). Dosing continued from post natal day (PND) 23 to 53, by gavage. Euthanasia was performed on PND 53; or, after an interval of 62 days without exposure to chemicals, on PND 115. The degree of maturation of the seminiferous epithelium was delayed in chemical-exposed groups and testicular interstitial oedema was observed at adulthood. The pattern of male gonad organization was changed in the Aroclor group on PND 53 and in all treated groups at adulthood. The animals from Aroclor, low mix and high mix groups showed a reduction in the number of Sertoli cells. Histological evidence of renal injury was observed in all chemical-exposed groups in both ages. A probable target for MeHg and Aroclor in the reproductive system was Sertoli cells, in which possible dysfunctions could be linked to the other testicular alterations. Curiously, the main deleterious effects were late outcomes, along with the absence of synergistic interaction of MeHg and Aroclor in the parameters investigated. In conclusion, fish pollutants MeHg and Aroclor caused permanent structural damage in male gonads and kidneys after prepubertal exposure, without showing clear chemical interactions.