Fig. 3.

Formation and repair of DPC in normal and GSH-depleted cells. DPC were measured by the K-SDS precipitation assay in cells collected immediately (0 h) and 24 h after 3-h long exposures to Cr(VI). Cr-induced DPC values are background subtracted and represent means ± SDs from three independent experiments in triplicates. Statistics: *P < 0.05 and **P < 0.01 relative to 24 h samples. (A) DPC levels in XP-A cells grown under standard tissue culture conditions. (B) DPC in XPA+ cells grown under standard conditions. (C) DPC in XP-A cells pre-treated with 0.1 mM BSO for 24 h prior to Cr(VI) treatments. (D) DPC in XPA+ cells pre-treated with 0.1 mM BSO for 24 h prior to Cr(VI) treatments. (E) Cellular levels of GSH in control and 0.1 mM BSO pre-treated cells (grey bars, XP-A cells; black bars, XPA+ cells). GSH concentrations were measured by HPLC detection of the specific GSH–monobromobimane conjugate.