Novel method for cell debris removal in the flow cytometric cell cycle analysis using carboxy‐fluorescein diacetate succinimidyl ester

Background: Cell cycle analysis with flow cytometry using propidium iodide (PI) can be difficult in some cases because of the cell debris. Here, we introduce d ebris r emoval using i ntranuclear p rotein s taining (DRIPS), a novel method for separating intact nuclei and cell debris to different populations using carboxy‐fluorescein diacetate succinimidyl ester (CFSE). Methods: To study the apoptosis‐sensitivity, chicken DT40 B cell lymphoma cell line was γ irradiated. After the irradiation, the cells were incubated up to 8 h and the stages of the cell cycle were followed with flow cytometry. Results: CFSE staining, done simultaneously with PI, stained the cell debris brighter than intact nuclei and could be excluded from the histogram with a simple gating procedure. The method is reliable and reproducible and can be executed within 15 min. Conclusions: DRIPS‐method greatly enhances the analysis of difficult cell cycle samples. © 2006 International Society for Analytical Cytology