Effect of acyclovir on the radiation-induced micronuclei and cell death

Treatment of HeLa cells with 0.1 μM Acyclovir [9-(2-hydroxyethoxymethyl)guanine] (ACV) before exposure to 0, 0.25, 0.5, 1, 2 and 3 Gy of γ-radiation resulted in a dose-dependent decline in the growth kinetics and cell proliferation indices at 20, 30 and 40 h post-irradiation when compared with the PBS + irradiation group. These results were reflected in the cell survival, which declined in a dose-dependent manner and the surviving fraction of cells was significantly lower in ACV + irradiation group than that of PBS + irradiation group. The effect of ACV + 1 Gy irradiation was almost similar to PBS + 3 Gy irradiation suggesting an enhancement of the radiation effect by ACV pretreatment. The frequency of micronuclei increased in a dose-dependent manner at all the post-irradiation time periods in both PBS + irradiation and ACV + irradiation group and it was significantly elevated in the latter when compared with the former group. The dose-response for both groups was linear. The surviving fraction of HeLa cells declined with the increasing MN frequency and a close linear quadratic correlation between cell survival and micronuclei-induction was observed. (C) 2000 Elsevier Science B.V.