Analysis of cell kinetics after irradiation by flow cytometry: proliferative ability of G2-blocked cells after cell sorting.

Irradiation, dose-dependently, increases the percentage of cells in the G2 + M phase and the duration of cell cycle arrest, reflected by changes in cell kinetics in the first 48 h. Cells in the G2 + M phase are considered radiosensitive but little is known about their proliferative ability. We studied proliferative ability of irradiated G2 phase-arrested cells following flow cytometric cell sorting using fluorescent Hoechst 33342 staining. Although proliferative ability of non-irradiated cells was not different between G1 and G2 + M phases, cells arrested in G2 + M after irradiation, especially at higher doses, showed less ability than cells in G1. Proliferative ability also correlated well with of G2 block duration.