Functional activity of mast cells in experimental thyrotoxicosis in cell culture

Abstract

The role of mast cells (MC) in the pathogenesis of autoimmune thyroid diseases has been discussed for decades. However, the exact role of MC in the pathogenesis of this autoimmune pathology remains largely unclear.
Aim. In this study, we investigate the effect of thyroid hormones on the functional activity of mast cells using a continuous cell culture.
Materials and methods. Mast cells of the human mast cells-1 line (HMC1) were cultured in two nutrient media. One series contained the T4 thyroid hormone, while the other – cultured simultaneously – served as a comparison group. 4',6-diamidino-2-phenylindole (DAPI) was used to stain necrotic cells; and 2’,7’-dichlorodihydrofluorescein diacetate (DCFH-DA) was used to stain cells with active mitochondria. The cultured mast cell media were analyzed for the cytokine content: INF-γ, TNF-α, IL-6, and free T4.
Results. The conducted culturing of mast cells reliably demonstrated the stimulating role of thyroid hormones on mast cell functional activity. The TNF-α level in the mast cell medium, cultivated without the addition of T4, increased 9-fold by day 7, compared to the baseline values. However, in mast cells cultivated with the addition of T4, TNF-α increased 29-fold during the same period. Thyroxine exerted a significant stimulating effect on mast cell function, manifested in a significant increase in the synthesis/production of TNF-α de novo. The experiment can be considered representative due to the use of the established mast cell line.
Conclusion. Mast cells respond to an increase in the thyroxine content in the environment with additional synthesis/production of TNF-α. The validity of the results obtained, determined by the use of the HMC1 line, allow us to assume that cell activation is also possible in vivo under changes in the synthesis or production of thyroxine by thyrocytes in the thyroid gland.