Modulação da função tireoidea e das iodotironias desiodases tipo 1 e 2 em ratas prenhas submetidas à restrição de sono e avaliação de sua prole

Abstract

Sleep is considered essential for life and maintaining homeostasis. During pregnancy occur a number of changes, including sleep patterns with decreased amount of sleep in the third trimester. Is already proven that sleep deprivation triggers oxidative stress in different organs and the induction of oxidative stress during pregnancy can lead to congenital malformations, fetal death, hormonal changes, decreased body weight gain in mother and offspring, however, no studies in the literature evaluating the effects of sleep restriction on thyroid function during pregnancy. Therefore we aimed to study the effect of sleep restriction on thyroid function and metabolism of iodothyronines extrathyroid in pregnant rats submitted to sleep restriction, in addition to evaluating the same parameters in their offspring. Virgin females (200-250g), in proestrus, were placed with males. The presence of spermatozoa in vaginal smear defined gestational day 1 and females were divided into control (C, n=15) and sleep restricted (SR, n=22). To sleep restriction used the Modified Multiple Platform Methodology starting the restriction on the 14th gestational day and ending on the 20th, when half of the rats (C=7 and SR=11) were euthanized and the remaining calved normally (C=8 and SR=11), with remaining until weaning puppies when they were euthanized along with part of the male pups (C=4 and SR=8) and female (C=6 and SR=7), the female pups (C=4 and SR=13) remaining were euthanized at 60 days of life. Body weight was followed during pregnancy. Thyroid, adrenal and pituitary were weighed for analysis of the absolute and relative weight. T4 (µg/dL), T3 (ng/dL) and corticosterone (ng/ml) serum were analyzed by RIA. The deiodinase type 2 activity (D2, expressed in fmol T4/min.mg.ptn) was evaluated in the pituitary, brown adipose tissue (BAT), hypothalamus and hippocampus. The deiodinase type 1 activity (D1, expressed as pmol rT3/min.mg.ptn) was evaluated in the liver, kidney, thyroid and pituitary. In the statistical test T-Student (p <0,05) was used. Approval of the ethics committee of UFRRJ No 23083.000361/2013-10. In pregnant SR rats, there was an increase in absolute adrenal weight, decreased levels of T4 and increased D2 activity in TAM on the 20th gestational day. In SR rats in weaning puppies, in addition to low serum T4, we found increased relative weight of adrenal and kidney D1 activity, and decreased activity D1 in pituitary and liver. In the offspring of SR during pregnancy, we found increased relative weight of the thyroid, T4 levels and corticosterone in male pups 21 days, and increased hypothalamic D2 activity in females 60 days. In conclusion, sleep restriction for 6 days in a pregnant rats affects thyroid function, decreasing serum T4, T3 levels now are probably maintained by the modulation of peripheral deiodination (D2 activity in high TAM), in addition, the restriction of sleep during pregnancy also alters the thyroid status of the offspring, which shows elevation in serum T4 concentration associated with normal levels of T3 and D1 activity.