DETECTION OF SUPEROXIDE AND NADPH OXIDASE IN PORCINE ARTICULAR CHONDROCYTES

Porcine articular chondrocytes have the capacity to release superoxide in response to the addition of the calcium ionophore ionomycin in a c oncentration-dependent manner. This activity was not stimulated by the addition of fMetLeuPhe or the kinase activator phorbol myristate acet ate (PMA). However, this release of superoxide was inhibited by iodoni um diphenyl (IDP), suggesting the involvement of NADPH oxidase. Revers e transcriptase polymerase chain reaction (RT-PCR) using oligonucleoti des designed against the known sequences for the human phagocyte NADPH oxidase showed the expression of p22-phox, p40-phox, and p47-phox mRN A, while Western blot analysis of chondrocyte extracts using polyclona l antisera raised against the human phagocyte NADPH oxidase suggested the presence of the p67-phox polypeptide. These results suggest that p orcine articular chondrocytes can release reactive oxygen species usin g a NADPH oxidase-like complex. (C) 1997 Elsevier Science Inc.