Abstract
Gingival epithelium provides the mechanical and biologica protective integument of the periodontium. Interleukin-1 (IL-1) is known to play an important role in the progression of periodontal inflammation, and IL-1 receptor antagonist (IL-1 ra) is identified as a specific inhibitor of IL-1. To clarify the expression of IL-1 and IL-1 ra in human gingival keratinocytes, we studied the protein production and mRNA expression of IL-1 a and IL-1 ra in human cultured gingival keratinocytes using enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR). Furthermore, we studied im-munohistochemically the presence of IL-1 a and IL-1 ra in the epithelium of healthy and inflamed gingiva. Results showed that IL-1 a was detected more than IL-1 β in cell lysates and conditioned medium. The level of cell-associated IL-1 a was significantly increased under stimulation of tumor necrosis factor-a (TNF-a), while the level of IL-1 a in conditioned medium and the levels of IL-1 β or IL-1 ra protein were not influenced by TNF-a. IL-1 a and intracellular IL-1 ra mRNA transcripts were enhanced under stimula-tion with TNF-a by RT-PCR. Furthermore, the presence of IL-1 ra, but not IL-1 a, was found by immuno-histochemistry in the epithelium of gingiva. These results indicatethat human gingival keratinocytes express IL-1 a and IL-1 ra, and may be involved in the regulation of inflammation of periodontal diseases by IL-1 a and IL-1 ra. J. Jpn. Soc. Periodontol., 41: 87-98, 1999.
