Morphological changes in the thyroid gland of rats of different age after administration of methionine

Background. Literature data on the effect of methionine on functional activity and, especially, on morphological changes in the thyroid gland are sporadic. This may be due to a number of reasons, such as: different ages of experimental animals; different dosage of methionine; different seasonality and duration of experiments. Aims: To investigate the morphological changes in the thyroid gland of rats of different ages after methionine administration. Material and methods. The experiments were performed on 48 Wistar male rats of 3 and 15 months of age. Experimental animals received methionine daily for 21 days at a dose of 250 mg / kg of body weight in addition to the standard diet. Histological preparations were made from the thyroid tissue according to the standard method. The gland morphometry was performed on digital images using the computer program Image J. Results. It was found that 21-day administration of methionine to rats of both 3 and 15 months of age led to a decrease in the cross-sectional area of the follicles and colloid, the accumulation index of colloid and the relative area of the conective tissue in the thyroid gland. But the follicular-colloid index, the number of resorption vacuoles in the colloid, and the number of interfollicular islets were increased. Morphological changes in the thyroid gland of 15-month-old experimental rats were manifested to a greater extent than in young animals. Conclusions. Thus, the influence of methionine increases the histomorphological signs of the synthetic activity of the thyroid gland in rats of different ages.