Harmful Effects of an Irradiated Cell Culture Medium

Summary

The Fischer medium used for growing L5178Y–S cells, after x-irradiation, exerts on these cells effects similar to those produced by irradiation of the whole cultures. In particular, growth inhibition, decrease of viability, cloning efficiency and of mitotic index are observed. Growth delay caused by irradiation of the medium with 10 000 rads is comparable to that caused by irradiation of the cell culture with 200 rads. Mitotic index under these conditions drops from 2·5 to 0·4 per cent within 1 hour after placing the cells in the irradiated medium. Viability reaches a minimum of ca. 25 per cent after 48 hours of growth in the irradiated medium. Harmful components of the irradiated medium are labile. Storage of the medium at 37°c for 48 hours leads to an almost complete restoration of the normal ability to support the growth of L5178Y-S cells. Part of the harmful properties is lost in a short time, e.g. 10 min incubation is sufficient to produce a significant restorative effect.