Induction of chromosomal aberrations by hypotonic culture conditions is independent of the S-phase in V79 hamster cells

A deviation from physiological osmolality (300 mOsm/kg H₂O) can lead to genotoxic effects. A 30-min treatment of V79 hamster cells with hy-potonic sodium chloride of 60 mOsm/kg H₂O or with diluted culture medium of the same osmolality induces extraordinarily high frequencies of chromosomal aberrations. In this study, multiple fixation times over a 24-hr period were used to identify cells in various stages of the cell cycle at the time of treatment and to find out whether or not hypotonic conditions are able to induce aberrations in all cell cycle stages. Because of the aberration pattern observed, it is suggested that hypotonic treatment acts as an S-independent agent, like X-rays or restriction endonucleases. Whether the aberrations originate from directly induced DNA damage or from a release of DNase after lysosomal breakdown is discussed.