Histomorphological features of the thyroid gland in rats of different ages with alimentary-induced obesity

The aim of the study was to compare histomorphological disorders of the thyroid gland in rats of different ages with alimentary-induced obesity. The study was carried out on male Wistar rats, aged six and 21 months. Alimentary obesity in animals was modelled by keeping them on a high-calorie diet (580 kcal 100 g‑1) for 12 weeks, with an excess content of fats and carbohydrates. Control animals were given a standard diet (330 kcal 100 g‑1). Histological preparations were made from thyroid tissue. Histomorphometry was carried out using the computer program “ImageJ”. It was revealed that a 3‑month high-calorie diet led to the appearance of pronounced histomorphological signs of thyroid hypofunction in rats. Intensive colloid resorption and a decrease in colloid area occurred in the gland. Devastated follicles were common. Thyrocytes acquired a prismatic shape. There was hyperplasia of the thyroid gland, which led to an increase in its size. The intensity of morphological disorders of the thyroid gland depended on the degree of obesity and had a distinct age-dependent character. In young rats, these changes were more pronounced than in older animals.