Journal of Education, Health and Sport (Apr 2020)

Seasonal features of the combined effects of intermittent normobabic hypoxia and melatonin on the thyroid gland morphofunctional state

  • Roman Yanko,
  • Mikhail Levashov,
  • Elena Chaka,
  • Irina Litovka,
  • Sergey Safonov

DOI
https://doi.org/10.12775/JEHS.2020.10.04.021
Journal volume & issue
Vol. 10, no. 4
pp. 186 – 198

Abstract

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The aim of this work is to compare the effect of the combination influence of dosed intermittent normobaric hypoxia and melatonin in different seasons of the year on the morphofunctional state of the rats’ thyroid gland.Material and methods. The study was carried out on 48 male rats of the Wistar line. The hypoxic gas mixture (12% O2 and 88% N2) was daily given to experimental animals in intermittent mode: 15 minutes deoxygenation / 15 minutes reoxygenation for 2 hours. Melatonin was administered orally in a dose of 5 mg / kg at10.00 a.m. The total duration of the experiment was 28 days. Histological preparations were prepared according to a standard methodic. Histomorphometry of the digital images of preparations was carried out using the computer program «Image J».Results. It was shown that the thyroid gland of rats reacted differently to the combined effects of intermittent hypoxia and melatonin at different seasons. So the signs of the gland activity were increased after influence of hypoxia and melatonin in spring. It was evidenced by a smaller area of follicles and colloid, a smaller internal diameter of the follicles and colloid-accumulation index, a greater height of the thyrocytes and follicular-colloid index, a smaller width of the interlobar, interlobular and interfollicular connective tissue interlayers compared to the control. The prolonged exposure to intermittent hypoxia and melatonin in autumn decreased the area and height of the follicular epithelium, increased the internal diameter of the follicles, decreased the follicular-colloidal index and increased the colloid-accumulation index. This indicated a decrease in the activity of the thyroid gland.Conclusions. Thus, in the spring, the morphofunctional activity of the thyroid gland is moderately increased, and in the autumn period, on the contrary, decreases.

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