Cytogenetic effects of argon laser irradiation on Chinese hamster cells

The cytogenetic effects of argon laser light on V79 Chinese hamster cells were studied. Irradiation with a defocused continuous beam from an argon laser at doses of 100 to 400 J/cm2 had dose-related cytostatic and cytocidal effects. Cell cycle analysis by flow cytofluorometric measurement indicated that argon laser irradiation induced a temporary block at the G2 + M phase. The survival curve after laser irradiation was exponential without an initial shoulder and the D0 value (34% lethal dose) was calculated as 170 J/cm2. A significant increase in sister chromatid exchange was observed after laser irradiation. Laser irradiation also induced chromatid and chromosome aberrations, most of which were breaks and gaps. These chromosomal changes are probably not an artifact of the experimental procedures such as the use of phenol red and antibiotics or spontaneously emitted uv light. No mutation at the Na+/K+-dependent ATPase locus was induced by argon laser irradiation. Although the mechanism by which an argon laser beam induces cytogenetic damage remains to be investigated, the possible involvement of hyperthermia seemed to be excluded.