Abstract: AIM: To explore cytotoxicity induced byγ-radiation and menadione sodium bisulfates on HeLa cells in order to develoPa new method for anticancer in gynecological oncology.METHODS: Alkaline comet assay was used to test tail moment and cometlength of the cellline after treatment with menadione or a combination of 4Gyγ-radiation with the drug.RESULTS: The values of tail moment of the cells treated only with 10,20,and 40 mmol·L^-1of menadione were 2,3,and 5 times as high as that of the control without treatment (P<0.01).The values of tail moment after treatment with a combination of 4 Gyγ-radiation with menadione were 2.5 -4 times as high as that only with the menadione (P<0.01).Differences were significant (P<0.01)between groups treated with 4Gyγ-radiation and 10,and 40mmol·L^-1of menadione,and the groups incubated only with menadione.Compared with the control,cometlength increased significantly in groups incubated only with menadione.Differences were significant between the groups incubated with the drug in concentrations of 10 and 40 mmol·L^-1,as well as 20 and 40 mmol·L^-1.Treatment of 4Gyγ-radiation combined with menadione significantly increased the cometlength in each group,as compared to that treated only with meadione.Differences were significance between groups incubated with the drug in concentrations of 10 and 40 mmol·L^-1,20 and 40 mmol·L^-1.CONCLUSION: Menadione can enhance the cytotoxicity to HeLa cells in combination withγ-radiotherapy.

Key words: pharmacodynamics, γ-radiation, menadione, alkaline comet assay, HeLa cells, cytotoxicity