High hydrostatic pressure and chromate-induced effects on cell cycle kinetics

Cell cycle kinetics was studied using the quenching of 33258 Hoechst fluorescence by bromodeoxyuridine incorporation to investigate effects of high pressure on the toxicity of a welding fume component--chromate. When exposing the glioma cells to 1 microM K2Cr2O7 at 1 bar, we observed a prolongation of DNA-synthesis phase, whereas cells exposed to 5 microM K2Cr2O7 did not pass through mitosis. Cells exposed to 1 or 5 microM chromate during the last part of DNA synthesis and during mitosis were not delayed in passing through mitosis. High pressure (100 bar) or pretreatment with pressure did not cause changes of cell cycle parameters. The combined exposure of 1 microM K2Cr2O7 and high pressure caused the same effect as observed for 1 microM K2Cr2O7 at 1 atm. However, an extra delay was observed in passing through mitosis for cells exposed to 100-bar pressure during the early part of their cell cycle.