Effect of L929 cell-conditioned medium on antioxidant capacity in RAW264.7 cells

Previously, we found that macrophage colony-stimulating factor (M-CSF) could reduce tert-butyl hydroperoxide (tbOOH)-induced oxidative injury in monocytes/macrophages. In order to find the mechanism by which M-CSF achieves this, we investigate the effect of M-CSF on the antioxidant system in murine macrophage RAW264.7 cells, using L929 cell-conditioned medium (L929-CM) as the source of M-CSF. The results show that L929-CM increased selenium-dependent glutathione peroxidase, non-selenium-dependent glutathione peroxidase, and catalase activities; and it increased reduced glutathione (GSH) but decreased lipoperoxide content in RAW264.7 cells. L929-CM-treated cells maintained their antioxidant capacity (including antioxidant enzyme activities and GSH content) when challenged with tbOOH. We conclude that M-CSF from L929-CM reduces oxidative injury in RAW264.7 cells by increasing antioxidant enzyme activity and improving redox status.