Compare two different staining methods used in flow cytometric analysis of cell cycle

Objective To compare the staining methods using PI and DAPI for flow cytometric analysis of cell cycle. Methods A549 cells stained after 0 hour and 24 hours with PI or DAPI were measured by Beckman Coulter QunataTM SC flow cytometry for the percentages of cells in G0 /G1, S and G2 /M phases. The results were analyzed and compared. Results The results of staining with PI or DAPI after 0 hour showed that CV values were (7.72±0.19) and (5.92±0.09),the percentages of cells in G0 /G1 were (69.63±1.16)% and (69.87±1.28)%, in S were, (24.53±0.47)% and (24.43±0.86)%, and in G2 /M were, (5.85±1.04)% and (5.72±0.65)%, respectively. The results from the two different methods showed no significant difference(P0.05). The results of staining with PI or DAPI after 24 hours, showed that CV values were (8.82±0.05) and (6.09±0.30), and the percentages of cells in G0 /G1 were (58.50±0.90)% and (70.47±0.81)%, in S were, (31.73±0.75)% and (23.67±0.45)%, and in G2 /M were,(9.51±0.47)% and (5.86±0.46)%, respectively. The results from the two different methods showed significant difference(P0.05). The results stained after 0 hour and 24 hours with DAPI showed no significant difference(P0.05), but those with PI showed significant difference(P0.05). In addition, the count of the cells changed after staining 24 hours. 12.50% cells lost in DAPI staining while 63.18% in PI staining. Conclusion Detecting cell cycle with flow cytometry, the method staining with DAPI is better than staining with PI.