International Journal of Radiation Biology vol:71 issue:4 pages:429-433
Human peripheral blood lymphocytes, irradiated In vitro, die by an apoptotic process. The number of apoptotic cells after in vitro gamma-irradiation (0, 0.1, 0.2, 1, 2 and 5 Gy) was measured by flow cytometry using Annexin V and DiOC(6) (a cationic dye) after 24 and 48h incubation. The mean dose-response curves for apoptosis of six healthy volunteers obtained with both methods were steep below 1Gy and flatter at higher doses. A slightly higher number of apoptotic cells was observed with DiOC(6), compared to Annexin V. This can be assigned to a minor DiOC(6)-int/PI- population. Forty-eight hour cultures contained higher numbers of apoptotic cells compared with 24h cultures. For both culture times, DiOC(6) and Annexin V detected a statistically significant difference between a control sample and a 0.1 Gy irradiated one, illustrating the high sensitivity of the methods.