Sex-related differences in morphofunctional changes of the rat thyroid after long-term exposure to low doses of DDT during postnatal development

One of the most urgent problems in medical science is the impact of endocrine disruptors on the functioning of endocrine glands. Of particular interest to scientists are the effects of low dose exposure to a widespread endocrine disruptor dichlorodiphenyltrichloroethane (DDT) on a developing organism. Due to the antiandrogenic effect of DDT, the study of patterns and particularities of morphological and functional changes in both sexes is extremely important for understanding mechanisms of action of this endocrine disruptor. The aim of this research was to study morphofunctional changes in the thyroid and identifying gender differences in Wistar rats exposed to low doses of DDT from birth to puberty. Animals in experimental groups were given a solution of o,p-DDT at a concentration of 20mkg / L for 6 weeks instead of water. Average daily consumption of o, p-DDT was 3,71 ± 0,15pg/kg. Quantification of serum concentrations of total thyroxine (T4), free thyroxine (fT4), total triiodothyronine (T3), free triiodothyronine (fT3) were performed by ELISA, using commercially available kits (“Cusabio Biotech”, China; “Monobind”, USA). Examination of histological slides of the rat thyroid after the PAS-reaction was performed by light microscopy and computer morphometry using “Image ProPlus” program (“Leica Microsystems”, Austria), separately in peripheral and central regions of the thyroid.The results of morphological, morphometric and biochemical analyses have shown that exposure to low doses of DDT led to a decrease in functioning of the gland in both rat males and females. Analysis of morphological changes in experimental groups compared to controls has shown that their character differs between males and females, but the most conspicuous changes were found in peripheral regions of the thyroid parenchima. In females, however, a smaller decrease in thyroxine production has been observed due to an increase in functioning of follicles in the peripheral regions of the thyroid and the beginning of microfollicular reconstruction in the central region.

щитовидная железа, эндокринные дисрапторы, ДДТ, морфология, половые различия, thyroid, endocrine disruptors, DDT, morphology, sex-related differences

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