Cases of folliculogenesis in the rat's thyroid gland in norm and under experimental conditions

Abstract

Objective: identification and characterization of the stages of formation of new follicles, as well as the frequency of folliculogenesis in various parts of the thyroid gland in the norm and in the experiment. Material and methods. The experiment was carried out on 36 mature white rats divided into three groups: control (I), 60-day exposure to sodium benzoate at a dose of 1000 mg/kg (II) and administration of mexidol at a dose of 50 mg/kg against the background of 60-day administration sodium benzoate (III). The stages of folliculogenesis were studied using light microscopy followed by a statistical analysis of its frequency. Results. The formation of a new follicle begins with the proliferation of thyrocytes on the wall of the mature follicle, after which a cavity is formed between the cells, into which they begin to secrete the colloid. In the process of follicle growth, the height of thyrocytes decreases, and the size of its cavity and the amount of colloid increase. In group II, signs of folliculogenesis were detected in the center of the organ by 1,7 and 1,4 times, and on the periphery — by 2 and 1,2 times less than in group I, and in group III — by 1,3 and 1,6 times more often in the center and 1,3 and 1,3 times in the periphery, compared with group II on the days 3 and 24 of the experiment. Conclusion. In the process of folliculogenesis in the thyroid gland, focal proliferation of thyrocytes develops in the wall of one of the follicles with further formation of the cavity of the newly formed follicle and its growth. In norm the frequency of new follicles formation is higher in the centre of the organ than in the periphery and decreases in both zones in the group of rats with sodium benzoate administration. In the group of rats where sodium benzoate administration was corrected by mexidol administration, the number of cases with the formation of young follicles increased, but the indicators did not reach the control figures.