Regulation of Cytokine and Cyclooxygenase Expression in Palatine Tonsils from Recurrent Tonsillitis in Children / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Prostanoids are converted from arachidonic acid via cyclooxygenase (COX), which has two isoforms, COX-1 and COX-2. It has recently been shown that prostanoids may have a novel role in mediating cytokine release in some cells. We investigated the baseline expression and regulation of interleukin (IL)-6, IL-8, COX-1 and COX-2 in palatine tonsils from pediatric recurrent tonsillitis. MATERIALS AND METHOD: Palatine tonsils were obtained from 12 children with recurrent tonsillitis during elective tonsillectomy and adenoidectomy. Tonsil cells were incubated with culture media only or with proinflammatory cytokines (IL-1beta and TNF-alpha) or inhibitors of transcription (actinomycin D) or translation (cycloheximide). In these groups, IL-6, IL-8, COX-1, COX-2 mRNAs and COX-1, COX-2 proteins were analyzed by reverse transcriptasepolymerase chain reaction and Western blot, respectively. RESULTS: The baseline expressions of IL-6, IL-8, COX-1 and COX-2 mRNAs were detected although tonsillectomy was done in the silent phase without acute infection. The culture of tonsil cells with pro-inflammatory cytokines increased the expression of IL-6, IL-8 and COX-2 mRNAs and COX-2 protein. The expressions of IL-6, IL-8 and COX-2 mRNAs and COX-2 protein induced by pro-inflammatory cytokines was significantly inhibited by actinomycin D, not by cycloheximide. CONCLUSION: Tonsil cells isolated from pediatric recurrent tonsillitis are in constantly inflamed state. The expression of COX-2 mRNA induced by pro-inflammatory cytokines is accompanied by the induction of IL- 6 and IL-8 mRNAs. The regulation of these effects occurs at the transcriptional level. Furthermore, the regulation of cytokines and COX-2 may provide an understanding of mechanism of prostanoids synthesis in chronic tonsillitis.