Regulation of Interleukin-6 Production by Cultured Human Thyrocytes

Objective To study the modulation of interleukin 6 (IL 6) generation from human thyroid cells. MethodsThyroid tissues were obtained at surgery from patients with Graves disease. IL 6 in the supernatant of cultured thyrocytes was detected with ultra sensitive ELISA. mRNA was extracted respectively from primary human cultured thyroidal cells under stimulated and unstimulated conditions,and semiquantitative reverse transcriptase polymerase chain reaction (RT PCR) technique was used for IL 6 mRNA detection. Results① In the basic conditions,thyroid cells can produce high concentration IL 6. Thyrotropin (TSH,10 3mU/L), tumor necrosis factor α(TNF α,10 -1 U/ml),interleukin 1(IL 1,10 U/ml) and adrenaline(10 -5 mol/L) significantly increased IL 6 levels in the supernatant of cultured thyroid cells,whereas dexamethasone (10 mmol/L) markedly suppressed IL 6 release from thyrocytes. NaI of 10 -4 mol/L exerted no effect on the production of IL 6. ② Compared with the basal results,at a concentration of 10-10 3 mmol/L,dexamethasone could gradually suppress IL 6 gene expression on human thyrocytes,while TNF α could obviously stimulate the production of IL 6 mRNA in the range of 10 -1 -10 2 U/ml. On the level of 10 2 U/ml,IL 1 increased the expression of IL 6,but the same effect could not be shown when IL 1 was 10 -1 or 10 U/ml. Sodium iodine (NaI) could not affect IL 6 gene from the level of 10 -8 to 10 -4 mol/L. ConclusionIL 6 produced by thyrocytes might be regulated by many factors that modulate thyroid functions in vitro as well as in vivo.