AIM To study the effect of 1,10-
phenanthroline(OP) on DNA oxidative damage and explore the damage mechanism initially.
METHODS CHL cells were pretreated with different concentration of OP for 30 min, then co-cultured with two tested toxic oxidants and doxorubicin for certain time course(0.4 mmol·L -1 hydrogen peroxide:25 min, 0.3 mmol·L -1
potassium chromate: 105 min, 0.5 μmol·L -1 doxorubicin: 75 min). OP was compared with dimethyl sulfoxide(DMSO) co-cultured with hydrogen pe- roxide to elucidate their inhibitory effect on DNA damage by hydrogen peroxide indirectly through production and clearance of ·OH, finally alkaline single cell gel
electrophoresis (ASCGE) assay was used to detect DNA strand breaks. RESULTS The DNA strand breaks were induced obviously after treated by 3 tested toxic agents respectively for certain time course. The DNA strand breaks induced by hydrogen peroxide or potassium chromate were antagonized completely by 12 μmol·L -1 OP. OP 3-6 μmol·L -1 is equal to DMSO 0.33 mol·L -1 in protection against DNA strand breaks by hydrogen peroxide via ·OH. Treatment of CHL cells with 10 or 30 μmol·L -1 OP resulted in a marked decrease in the DNA breaks induced by doxorubicin, but the DNA breaks still could not be antagonized completely when the concentration of OP up to 60 μmol·L -1. CONCLUSION The treatment of CHL cells with OP resulted in a marked decrease in the DNA strand breaks caused by 3 tested toxic agents, i.e., OP has a protection from DNA damage. The results also suggest that the production of ·OH which closely related to the transition metal ion plays a major role in DNA damage induced by hydrogen peroxide or potassium chromate, but doxorubicin-induced DNA damage is only in part related to that.