| Summary: | 碩士 === 長庚大學 === 天然藥物研究所 === 91 === The superoxide anion generation effect of celecoxib, a selective cyclooxygenase-II inhibitor, on human neutrophils was evaluated in this study.
Celecoxib induced superoxide anion production in human neutrophils with a concentration-dependent manner. The EC50 value of celecoxib on superoxide anion generation is 29.5 ±6u M.This effect was inhibited by a NADPH oxidase inhibitor (DPI), indicating that respiratory burst was activated by celecoxib. PKC inhibitor (staurosporine、Go-6976 or Ro-318220) and BAPTA/AM inhibited celecoxib-induced superoxide anion release on human neutrophils, indicating that PKC activation and calcium mobilization involved in celecoxib-induced superoxide anion release. Furthemore, celecoxib caused translocation of PKC-α、β from cytosolic plasma to cellular membrane. PIP2-PLC inhibitor (U73122) and PA-A inhibitor (propranolol) inhibited superoxide anion production, but PLD inhibitor (1-butanol) and PC-PLC inhibitor (D609) were not effects. Wortmannin (100 nM) and PD98059 (15 uM) did not inhibit superoxide anion production caused by celecoxib, this data indicated that PI3K and MAPK didn’t involved the productions of superoxide anion induced by celecoxib. Pertussis toxin (2 ug/ml), a Gi-protein sensitive inhibitor, significantly inhibited intracellular calcium mobilization and PKC-α translocation from cytosloic plasma to membrane.Indomethacin (2 uM) was not increase superoxide anion production, in this result indicates rule out superoxide anion production through COX-I and COX-II.
Treatment of human neutrophils with celecoxib induced β-glucuronidase release. In this study, we hypothesized that celecoxib possibly induced cytokines secretion in human neutrophils. Celecoxib induced superoxide anion generation was partially reversed after pretreatment of TNF-α neutralization antibody (10 ug/ml).In addition,celecoxib also induced β2 integrin expression, and this effect was inhibited by SOD (150 U/ml).These results indicates that the superoxide anion may participate in celecoxib induced β2 integrin expression. We also observed that β2 integrin expression was inhibited by genistein (20 uM)、PD98059 (15 uM) and SB203580 (15 uM). These results indicates that tyrosine kinase and MAP kinase maybe involved in β2 integrin expression caused by celecoxib.
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