Instances of folliculogenesis in rat thyroid: The norm vs. the experiment

Objective: identification and characterization of the stages of new follicle formation, along with measuring the frequency of folliculogenesis in various parts of the thyroid in normal and experimental conditions. Materials and Methods. The experiment was performed on 36 mature white rats distributed among three groups: the control (Group I), 60-day exposure to sodium benzoate at a dose of 1,000 mg/kg (Group II), and administration of Mexidol at a dose of 50 mg/kg against the background of a 60-day exposure to sodium benzoate (Group III). The stages of folliculogenesis were studied using light microscopy followed by statistical analysis of its frequency. Results. The formation of a new follicle begins with the proliferation of thyrocytes on the cell wall of the mature follicle, after which a cavity is formed between the cells into which they secrete colloid. As the follicle grows, the height of the thyrocytes declines, and the size of their cavity and the amount of colloid increase. In Group II vs. Group I, on days 3 and 24 of the experiment, signs of folliculogenesis were detected 1.7 and 1.4 timesless frequently in the thyroid center, and 2 and 1.2 times less often in the thyroid periphery; while in Group III vs. Group II, these were observed1.3 and 1.6 timesmore often in the center of the organ, and 1.3 and 1.3 times more frequently in the thyroid periphery. Conclusion. During folliculogenesis in the thyroid, focal proliferation of thyrocytes develops in the cell wall of one of the follicles with further formation of the cavity of the newly formed follicle and its growth. Normally, the formationfrequency of new follicles is higher in the organcenter vs. the periphery and lower in both thyroid zones in the group of rats exposed to sodium benzoate. However, in the group of rats where sodium benzoate administration waspharmaceuticallycorrected by Mexidol, the frequency of the young follicleformation increased, albeitit did not reach the control values.