EFFECTS OF INTERLEUKIN-1-BETA ON SCANNING ELECTRON-MICROSCOPIC APPEARANCE AND THYROID PEROXIDASE CONTENT OF HUMAN THYROCYTES IN MONOLAYER-CULTURE

Interleukin (IL-1), an inflammatory cytokine that is detected in the t hyroid tissues of patients with autoimmune thyroiditis, is believed to be involved in the disease process. To clarify the role of IL-1 in th e development of autoimmune thyroiditis, we investigated the effects o f interleukin-1 beta (IL-1 beta) on the morphology of human thyrocytes in monolayer culture as well as the effect on thyroid peroxidase (TPO ) content of these cells. Human normal thyrocytes were cultured with I L-1 beta for 4 days in the presence and absence of TSH. In morphologic studies, cultured cells were fixed for examination by scanning electr on microscopy and for immunofluorescent staining of actin filaments. I L-1 produced striking morphologic changes in the cultured thyrocytes, including the cytoplasmic retraction and dissociation and/or depolymer ization of actin filaments. These changes were unrelated to TSH stimul ation. For detection of TPO, cultured cells were stained by an immunof luorescent technique and analyzed by fluorescence photometry. IL-1 red uced the TPO content and inhibited the TSH-induced increase in TPO in a concentration-dependent manner. These morphological changes and the reduction in TPO content of cultured thyrocytes suggest that IL-1 modu lates the pathophysiology of autoimmune thyroiditis.