Effects Of Sodium Iodide And IL-1β On The Expression Of TRAIL In Human Thyrocytes

Objective: This research aims to investigate the effects of sodium iodide and IL-1βon the expression of TNF-related apoptosis-inducing ligand(TRAIL) and apoptosis of human thyrocytes primary cultured in vitro . Through combining the factors such as sodium iodide,cytokine IL-1β,autoimmunity and apoptosis in the thyroid follicular epithelial cells,we could discuss the relationship among them and investigate the effect of iodine and ocytokine IL-1βin the apoptosis of thyroid cells and the role of apoptosis in autoimmune thyroid disease, which also provides a new proof to diagnose and chemical treatment for the thyroid disease.Methods: Thyrocytes were primary cultured in vitro from normal or Graves' disease and Hashimotos thyroiditis' surgery patients. Immunocytochemical investigation with DAB-visualization and hematoxylin staining in the fixed thyroid epithelial cells was conducted to analyze the expression of thyroglobulin. Thyroid epithelial cells were cultured in the absence or presence of sodium iodide with different concentrations,which were distributed into normal control,HT and GD groups.Expressions and distributions of TRAIL in thyrocytes with HT,GD and normal cases were investigated with immunocytochemical method with DAB-visualization and hematoxylin staining.The positive rate of TRAIL and apoptosis were detected by flow cytometry. Thyroid epithelial cells were cultured in the absence or presence of cytokine of IL-1βwith different concentrations,which were also distributed into normal control,HT and GD groups. The proliferation of thyrocytes was determined by MTT.The positive rate of TRAIL were detected by flow cytometry. Results: (1)Positive immunostained protein in thyroid follicular cells for TRAIL is amber-yellow coloured and distributed in the cytoplasm or cytomembrane. The positive-stained cells from GD and HT are more profound and broarder than from the normal control. (2)The positive rates for TRAIL in the thyrocytes increased in the order of normal control group, GD group and HT group. (3)Under the induction of higher concentration of iodide ,the positive rate for TRAIL is increased.When the concentration of sodium iodide was 10mg/L,the positive rate in the normal group was significantly higher than that of 1mg/L .the same result showed in the GD group .But in the HT group, the 100mg/L concentration of sodium iodide was significantly higher than that of 1mg/L. (4)The rate of apoptosis in the human thyrocytes from HT group is significantly higher than that from the normal or GD group. What's more ,the excess concentration of sodium iodide could obviously induced the rate of apoptosis of thyroid cells. (5)The analysis of relationship between the rate of apoptosis of thyroid cells and the positive rate for TRAIL is significant. (6)Under the induction of higher concentration of cytokine of IL-1β,the positive rate for TRAIL is increased in the group of normal,GD and HT. When the concentration of IL-1βwas 500 - 1000pg/ml,the positive rate was significantly higher than that of 0pg/ml-250pg/ml. The rate of proliferation of thyrocytes was significantly inhibitived.Conclusions: The expression of TRAIL in the human thyrocytes from GD or HT is higher than those from the normal. Under the induction of excess iodine or IL-1βthe expression of TRAIL is increased ,which may induced the apoptosis of thyroid cells,and further lead to functional and pathologic changes of thyroid grand.