Exposure to gamma-Irradiation Increases Phorbol Myristate Acetate-Induced H2O2 Production in Human Macrophages

摘要

Cell number, protein, and phorbol myristate acetate (PMA)-induced hydrogen peroxide H2O2 production were measured in cultured human peripheral blood monocytes for six days after exposure to varying doses of gamma radiation. Both the number of adherent cells and the protein per dish decreased with increasing radiation doses. The dose of radiation decreasing the number of adherent cells by 37% on days 4 and 6 postirradiation there was 29 Gy. Superoxide levels were not significantly changed in cells exposed to 20 Gy. Catalase, glutathione peroxidase, and superoxide dismutase levels also were unchanged. Culturing irradiated cells with gamma interferon increased PMA-induced H2O2 release, which indicated that irradiated cells retained their capacity to respond to gamma interferon. These data demonstrate that irradiation affects the PMA-induced H2O2 production of human monocytes in a time- and dose-dependent manner. An increase in the release of reactive oxygen intermediates by the macrophage may play a role in enhancing the deleterious effects of radiation in vivo.