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 fibroblast cell line L929 with amounts of selenium and α-tocopherol sufficient to protect against peroxide damage. Supplementation of the culture medium with 30μM α-tocopherol or 50 nM sodium selenite led to a substantial increase of cellular α-tocopherol concentrations from 18 ± 3.0 to 3179 ±93.0 pmol/106 cells or cellular selenium concentrations from 0.17 ±0.02 to 1.75 ±0.16 ng/106 cells, respectively. L929 fibroblasts grown in selenite-containing medium also had markedly raised activities of both cytosolic glutathione peroxidase (from 11 ±0.9 to 67.2 ±4.2 mU/107 cells) and phospholipid hydroperoxide glutathione peroxidase (from 0.2 to 9.5 ±0.9 mU/107 cells). Supplementation with α-tocopherol inhibited single-strand breaks induced by low concentrations of H2O2 only, whereas an adequate selenium supply almost completely inhibited single-strand breaks induced by up to 30μM H2O2 and also significantly reduced H2O2induced cell death. An inadequate selenium supply and corresponding increase of GPx activity upon selenite supplementation was also observed with other cell lines, for instance, D10N, ECV-304, HepG2, and THP-1. Our data strengthen the relevance of standardized and adequate supplementation of tissue culture media with antioxidants to improve viability and genetic stability of cultured cells in general and in particular, if they are oxidatively challenged.