Análise morfométrica e imunohistoquímica das gônadas da prole de matrizes induzidas ao hipotireoidismo e tratadas com melatonina

Abstract

Fetal development is vulnerable to complications of hypothyroidism in pregnancy, leading to a high rate of miscarriages, premature births, and weight changes. Melatonin is a hormone that is closely related to the maintenance of gestation, in addition to regulating thyroid physiology. Our objective was to investigate the effect of the action of melatonin at 10 mg / kg in rats induced hypothyroidism during gestation, as well as in the gonads of their offspring. Fifteen pregnant rats were used, divided into 3 groups: GC: rats without induction to hypothyroidism; GH: rats induced hypothyroidism; GHM: rats induced hypothyroidism and treated with melatonin. Hypothyroidism was induced by oral administration of propylthiouracil (1mg / animal) and melatonin was administered subcutaneously (10mg / kg). Both treatments were performed during gestation and lactation. The gonads of the pups were collected for morphometric analysis and immunohistochemistry of cell proliferation and the thyroids of pups and matrices for morphometric analysis. The results showed that TSH dosing confirmed hypothyroidism in the matrices of the untreated group, where there was a significant reduction (p <0.05) when compared to the control and treated groups with melatonin. In the pups, there was no significant difference (p> 0.05) in TSH levels between groups. The weight of the ovaries, thyroids and the number of pups of the matrices with hypothyroidism presented a significant reduction (p <0.05) when compared to the other groups. Similarly in the thyroid, there was a decrease (p <0.05) in follicular diameter, height and epithelial proportion in the hypothyroid group. Body weight gain, however, showed a significant reduction (p <0.05) in the hypothyroid group when compared to the control group, but the melatonin group did not differ from any of the groups. The offspring of the matrices of the hypothyroid group showed a significant (p <0.05) reduction in body weight, gonads and thyroid weight, as well as the gonad cell proliferation index, when compared to controls and hypothalamus groups treated with melatonin. In view of the results, it can be concluded that the treatment with melatonin proved to be beneficial to prevent the effects of maternal hypothyroidism on the offspring of rats, reinforcing their ability to regulate organogenesis during gestation.