EFFECT OF INTERVAL FASTING ON MORPHOLOGICAL CHANGES IN THE RAT THYROID GLAND OF DIFFERENT AGE

Abstract

Despite of the well-studied effect of interval fasting on the body, literature data on its infl uence on functional activity and, especially, on morphological changes in the thyroid gland are sporadic. The research results are often contradictory, which may be due to differences in experimental conditions. The aim of this study was to investigate the morphological changes in the rat’s thyroid gland of different ages, which were on interval fasting. The experiments were performed on 48 male Wistar rats aged 4 and 16 months. The experimental rats underwent interval fasting (1 day complete fasting / 2 days standard diet). Duration of experiment was 28 days. Thyroid tissue preparations were made according to standard histological methods. The morphometry was performed on digital images using a computer program Image J. It was found that the colloid area, the interior diameter of the follicles and colloid accumulation index were decreased in 4 and 16 month-old rats after interval fasting. The relative connective tissue area was also decreased in 16-month- old rats. But the follicular epithelium height, the follicular-colloidal index and the number of interfollicular islets were increased. The morphological changes of the thyroid gland tissue in 16-month-old experimental rats were manifested to a greater extent than in young animals. Thus, after exposure to interval fasting, morphological signs of activation of the thyroid gland synthetic activity in rats of different ages were observed. Key words: interval fasting, thyroid gland, morphometric indicators.