CONVENTIONAL CELL-CULTURE MEDIA DO NOT ADEQUATELY SUPPLY CELLS WITH ANTIOXIDANTS AND THUS FACILITATE PEROXIDE-INDUCED GENOTOXICITY

Commercially available calf serum did not supply the cultured murine f ibroblast cell line L929 with amounts of selenium and alpha-tocopherol sufficient to protect against peroxide damage. Supplementation of the culture medium with 30 mu M alpha-tocopherol or 50 nM sodium selenite led to a substantial increase of cellular alpha-tocopherol concentrat ions from 18 +/- 3.0 to 3179 +/- 93.0 pmol/10(6) cells or cellular sel enium concentrations from 0.17 +/- 0.02 to 1.75 +/- 0.16 ng/10(6) cell s, respectively. L929 fibroblasts grown in selenite-containing medium also had markedly raised activities of both cytosolic glutathione pero xidase (from 11 +/- 0.9 to 67.2 +/- 4.2 mU/10(7) cells) and phospholip id hydroperoxide glutathione peroxidase (from 0.2 to 9.5 +/- 0.9 mU/10 (7) cells). Supplementation with cu-tocopherol inhibited single-strand breaks induced by low concentrations of H2O2 only, whereas an adequat e selenium supply almost completely inhibited single-strand breaks ind uced by up to 30 mu M H2O2 and also significantly reduced H2O2-induced cell death. An inadequate selenium supply and corresponding increase of GPx activity upon selenite supplementation was also observed with o ther cell lines, for instance, D10N, ECV-304, HepG2, and THP-1. Our da ta strengthen the relevance of standardized and adequate supplementati on of tissue culture media with antioxidants to improve viability and genetic stability of cultured cells in general and in particular, if t hey are oxidatively challenged.