Takatoshi Tanabe (1,2), Hitomi Otani (1), Katsuyuki Mishima (1), Ryokei Ogawa (2) and Chiyoko Inagaki (1,*)
(1) Department of Pharmacology and (2) Department of Orthopaedic Surgery,
Kansai Medical University, Moriguchi, Osaka 570, Japan
(*) To whom correspondence should be addressed.
Abstract: We successfully detected the oxyradical production in human synovial A (macrophage-like) and B (fibroblast-like) cells by phorbol 12-myristate 13-acetate (PMA) using the luminol-chemiluminescence method. The PMA (0.1 microg/ml)-induced photon generation was abolished by an O2- scavenger, superoxide dismutase, and an H2O2 scavenger, catalase, suggesting that the stimulus produced oxyradicals in synovial cells. Both of these responses were abolished by a protein kinase C (PKC) inhibitor, calphostine C, but unaffected by an intracellular Ca2+ chelator, BAPTA-AM, and Ca2+ removal from the extracellular medium. These findings suggest that synovial A and B cells produce oxyradicals through PKC-mediated and [Ca2+]i-independent mechanisms, probably through the activation of NADPH oxidase.
Keywords: Synovial cell, Oxyradical production, Protein kinase C