Fluorescent light-induced chromosome damage and its prevention in mouse cells in culture

Twenty-hour-exposure to fluorescent light produces chromatid breaks in a line of adult mouse lung cells grown in Dulbecco-Vogt medium supplemented with fetal bovine serum. The light-induced damage appears to be enhanced by increasing the concentration of oxygen in the gas phase of the culture. The effective wavelength(s) of light is in the visible range between 400 and 450 nm andis probably the mercury emission peak at 405 or 436 nm. Addition of catalase or glutathione with ascorbic acid to the culture medium reduced the number of chromatid breaks to a level not significantly different from that in the shielded cultures. It thus appears that the production of H2O2 in the culture medium or in the cell is responsible for the chromatid breaks. Most of the chromosomal abnormalities observed in long-term culture of mouse cells may result from exposure of cells or medium to fluorescent room lights in the presence of atmospheric oxygen. These genetic abnormalities can be minimized by shielding cells and medium from light, lowering the PO2 of the medium, and including reducing agents such as glutathione and ascorbic acid in the medium formulation.