Efeitos da exposição materna ao Triclosan, durante a prenhez e lactação, no desenvolvimento físico, instalação da puberdade e morfofisiologia ovariana da prole feminina de rato

Abstract

Epidemiological, clinical, and experimental studies are suggesting the increase of the incidence of reproductive abnormalities and fertility decline, as well as several hormone-dependent cancers of both sexes. Triclosan (TCS) is an antimicrobial agent used in industrialized products, especially personal care and oral hygiene. Particularly in dentistry, this substance is widely used in dental dentifrices and mouthwashes, obtaining excellent results in control of biofilm and avoiding installation and progression of carious and periodontal lesions. Several studies are concern about TCS as lately this compound has been included in the list of endocrine disrupters because of their adverse effects initially observed in aquatic fauna and confirmed in mammalian and human investigations. So, the objective of the present study was to evaluate the effects of maternal exposure to TCS, during pregnancy and lactation, on physical development, on puberty and on ovarian morphology of female offspring. For this purpose, pregnant rats were treated once a day orally during pregnancy and lactation as follows: Group I (GI): composed of 8 rats from the control group that received only corn oil under the same experimental conditions other groups; Group II (GII): composed of 8 rats that received TCS diluted in corn oil at a dose of 75mg / kg / day; Group III (GIII): composed of 8 rats that received TCS diluted in corn oil at a dose of 150mg / kg / day; Group IV (GIV): composed of 8 rats that received TCS diluted in corn oil at a dose of 300mg / kg / day. The female offspring were evaluated for external signs of physical development, puberty and at 90 days were euthanized for weighing and collection of ovaries for histological analysis. The results showed that the animal body weight was significantly lower in all TCS treated groups. Animals from all groups exposed to TCS were delayed on the day of vaginal opening and on the first estrus, showing delay in the onset of puberty. In addition, there was a reduction in the number of estrous cycles, associated with decrease in the frequency of the proestrus phase and increase in the methaestrus phase. The female offspring of TCS treated mothers had lower folliculogenic activity associated with increased TCS dose. It is concluded that maternal exposure to triclosan, during gestation and lactation, causes delayed puberty, dysregulation of the estrous cycle and reduction of folliculogenic activity in the female offspring of the rat. Key words: Triclosan,