Fig. 3.

Foci formation of γH2AX and pATM in Hela, HepG2 and MEC-1 cells observed by immunofluorescent microscopy. The three cell lines are exposured to 0.5, 1, 2 and 4 Gy ¹²C⁶⁺ and subsequently incubated for 0.5, 4 and 24 h for γH2AX and pATM in vitro. a, b, c γH2AX; d, e, f pATM; a, d Hela cells; b, e HepG2 cells; c, f MEC-1 cells. *P < 0.05 vs. 0 Gy irradiation; **P < 0.01 vs. 0 Gy irradiation. Over 800 randomly selected cells were counted. Cells with three or more foci of any size were classified as positive. Results are the means and SD for the three experiments