Fig. 4.

Effects of Asc supplementation on DPC formation and repair. Cells were pre-loaded with 0.5 mM Asc during a 90-min long incubation with 1 mM DHA prior to Cr(VI) exposures. DPC data are means ± SDs from three independent experiments in triplicates. Statistics: *P < 0.05, **P < 0.01 and ***P < 0.001 relative to 24 h samples. (A and B) DPC in Asc-supplemented XP-A and XPA+ cells, respectively. (C) Cellular levels of Asc in control and 1 mM DHA-treated XP-A and XPA+ fibroblasts. Asc concentrations were measured by HPLC. (D) Cr–DNA binding in Asc-preloaded XP-A and XPA+ cells treated with 20 μM Cr(VI) for 3 h and collected immediately. (E) Ethidium bromide-stained agarose gels of DNA fragments generated during DPC measurements.