INFLUENCE OF ORGANOTIN ON THYROID MORPHOPHYSIOLOGICAL STATUS

Tributyltin is an environmental contaminant found in antifouling paints, widely used in ships and other vessels. TBT causes endocrine-disrupting effects in mammals, due to its possible transfer through marine food chains, and the consequent consumption of contaminated seafood. Thus, we aimed to evaluate whether the treatment with TBT could induce histophysiological changes in the thyroid gland. TBT promoted disorganization of parenchyma, fibrosis and vascular congestion in the gland. Moreover, morphometric analysis showed statistically significant changes in the follicle of rats treated with TBT, with increased colloid and epithelial area, besides increased epithelial/colloid area relation, but no statistical differences were found in epithelial height. Nevertheless, collagen deposition was seen in the thyroids of treated groups. In thyroid physiological status, we did not observe intergroup significant changes in plasma levels of total T3 and T4 after treatment, even though we have found a time-dependent increase of T4 levels in TBT-treated groups. We also detected an increased H2O2 production in the thyroid of TBT-treated group, besides increased dual oxidase protein levels, the main enzyme involved in hydrogen peroxide production. Since H2O2 is a reactive oxygen specie, TBT could induce oxidative stress, what could be involved in the morphophysiological changes observed in the gland. These data provided the evidence that exposure to TBT induces morphophysiological changes in the thyroid gland, and may therefore correspond to a potential risk factor for thyroid disorders.