HYDROGEN-PEROXIDE IN RELATION TO PROLIFERATION AND APOPTOSIS IN BHK-21 HAMSTER FIBROBLASTS

Addition of H2O2 at 100 mu M, or 1 mM, to the culture medium of BHK-21 fibroblasts results in increased intracellular levels of H2O2 Whilst exposure of BHK-21 cells to lower levels of H2O2 (1 mu M) actually sti mulates proliferation, these higher oxidant concentrations not only de press proliferation rates but also lead to an increase in the appearan ce of apoptotic-like cells in the cultures. Other agents such as inhib itors of glutathione peroxidase and catalase, or mimics of superoxide dismutase, which also bring about elevated cellular levels of H2O2 in BHK-21 cells, similarly lead to decreased proliferation and an apparen t increase in cells with apoptopic features. Thus intracellular condit ions which are considered more prooxidant than normal, appear to favou r apoptosis over proliferation in BHK-21 fibroblasts. Additionally the se abnormal cellular conditions also appear to favour excessive DNA re plication, in remaining non-apoptotic cells.