On the Regulatory Capabilities of Thyroid Mast Cells in Thiamazole Model of Hypothyroidism and Infrared Laser Exposure

Abstract

The regulatory effect of mast cells on the state of thyroid gland in hypothyroidism and laser therapy remains unclear. Aim: to study the secretory processes of mast cells in relationship with the indicators of functional activity of thyroid gland. Materials and methods. Experimental groups: (55 rats) 1) intact rats, 2) hypothyroidism (thiamazole 25mg/kg) 3) hypothyroidism and 0.5W laser exposure, 4) hypothyroidism and 2.0W laser exposure. Histological samples of the thyroid gland were removed on the 1, 7, and 30 days. Histological sections were stained with toluidine blue. Morphometric data analysis included descriptive statistics and non-parametric tests (Mann Whitney, Spearman correlation coefficient). Results. The increase in the granular saturation of mast cells and the average histochemical coefficient was observed in the hypothyroidism group, the degranulation index increased by day 30. After 0.5 W laser exposure, there was a decrease in the granular content in mast cells and an increase in the degranulation index; the granular saturation increased by day 30. After 2.0 W laser exposure, the content of granules in mast cells decreased on day 1, and on days 7 and 30 it was higher than in the hypothyroidism group; the degranulation index decreased by day 30. The correlation was revealed between the indicators of granule accumulation in a mast cell, the index of mast cell degranulation, the thyroid epithelium height, and relative vascular area. Conclusions. The synthesis processes prevailed over secretion for mastocytes in thiamazole hypothyroidism. 0.5 W laser exposure was more effective for stimulation of the secretory processes in mast cells compared to 2.0 W exposure. The secretory activity of mast cells was associated with the functional activity of thyroid gland, which confirms their regulatory role in tissue repair after thiamazole induced hypothyroidism modeling.