Função tireoidea em ratos machos e fêmeas submetidos ao exercício isométrico e a privação de sono paradoxal

Abstract

Modern life has diminished the sleep time for the majority of the population, and the consequences of this reduction have been studied both in humans and animal models. In spite of this, only a few studies elucidate the effect sleep deprivation has on the thyroid function, as well as studies on any role exercise might have in the prevention of such alterations. The objective of this study is to assess the protective effect of the strength exercise on the thyroid function in rats that went through paradoxical sleep deprivation for 24 and 96 hours, as well as a rebound sleep for 24 hours. For this study male and female Wistar rats were used (200-250g), submitted to sleep deprivation using the modified multiple platforms, and the isometric exercise was offered by the inverted box proposed by Lac & Cavalie (1999). The animals were distributed in 6 groups: Control (C, males n=8, females = 13); Trained (T, males n=8; females n=13), Trained, with Sleep Deprivation of the paradoxical sleep for 24 and 96 hours (respectively TPSP24 e TPSP96 males n=10; females n=13); Trained with Sleep Deprivation for 24 and 96 hours, plus a rebound sleep for 24 hours (TPSP24R e TPSP96R males n=10; females n=13). All animals went through and adaptation to the strength exercise for 5 days, enduring 5 series of 30 seconds of strength with rest periods of 25 seconds between each series. After adaptation, an extra weight was added to the animal's tail. All animals were killed on the same day and their blood was collected for analysis of T3 (ng/dL), T4 (ug/dL), e TSH (ng/mL) using the radioimmunoassay technique. Ethics committee approval was granted by number UFRRJ Nº003/2015. After the statistical analysis we observed a significant body weight loss, both in females and males, and a relative loss in hypophysis weight in males from group T. On the other hand, the relative weight of the adrenal was reduced in the T group of males, and increased in both the T and TP24 groups of females. In males, seric TSH levels have risen with the exercise, normalizing after the deprivation of 24 and 96 hours, and the rebound in the PS96 group. The PSP was able to induce a raise in the T3 level in the groups TP24 and TP96 in males – no significant alterations were observed in females. As for the seric T4 in males, there was no alteration, although in females the 24 hours PSP was able to rise those values. This study indicates a protective effect by the isometric exercise, preventing TSH and seric T4 and T3 alterations induced by deprivation of the paradoxical sleep. As such more studies are necessary to clarify the mechanisms involved in such protection