Correlation of micronuclei-induction with the cell survival in HeLa cells treated with a base analogue, azidothymidine (AZT) before exposure to different doses of γ-radiation

The effect of 0.1 μM azidothymidine (AZT) a pyrimidine analogue has been studied on the growth kinetics, cell survival and micronuclei formation in HeLa cells exposed to 0, 0.25, 0.5, 1, 2 and 3 Gy of ⁶⁰Co γ-radiation. The AZT pretreatment resulted in a significant decline in the cell growth kinetics, cell survival and cell proliferation indices when compared with the PBS+irradiation group at 20, 30 and 40 h post-irradiation. Conversely, the frequency of micronucleated binucleate cells (MNBNC) elevated in a dose dependent manner in both PBS+irradiation and AZT+irradiation group. This elevation in MNBNC-induction was significantly higher in the latter when compared with the former group at all post-irradiation scoring time periods studied. The dose-response relationship for micronuclei induction for both the PBS+irrradiation and AZT+irradiation groups was linear. The biological response was studied by correlating the cell survival with MNBNC-induction. The cell survival and MNBNC-induction showed a close but inverse relationship and this relationship gave a best fit on the linear quadratic model.