The comet assay for the evaluation of cell resistance to oxidative stress

Oxidative stress caused by reactive species of oxygen, damages cellular DNA , proteins and lipids and is widely recognised as one of the causes of the development of chronic disease. If we could understand to what extent a cel l can contrast such oxidants, it would help towards preliminary screening o f the antioxidant action in the organism. We used a technique that quantifi es cellular DNA damage, the Comet assay or Single Cell Gel Electrophoresis to evaluate the resistance of human primary lymphocytes to an ex vivo treat ment with H2O2 before and after the intake of a diet with high or low amoun ts of antioxidants. Two concentrations of H2O2 (300 mu M and 500 mu M) were used and a dose dependent damage of cellular DNA was registered [F(1,18)= 13.003; p= 0.002]. A lower DNA damage was produced by H2O2 at both the conc entrations after the intake of the diet rich in antioxidants. The results obtained in our conditions seem to demonstrate that the evaluat ion of DNA damage by means of the Comet assay is a useful method to analyse the oxidative stress and the antioxidant capacity of the cells when challe nged with H2O2 (C) 1999 Elsevier Science Inc.