Analysis of Cell Cycle Regulation and Apoptosis Using Annexin-V and Propidium Iodide (PI) Staining

Since the introduction of flow cytometry-based methods, studies of cellular apoptosis have been significantly improved. By measuring changes in plasma membrane integrity and permeability, Annexin-V and Propidium Iodide (PI) are widely used in determining viable, apoptotic, or necrotic cells. The Annexin-V/PI protocol is a commonly used approach for studying apoptotic cells. The reason PI is used more often than other nuclear stains is that it is economical, stable, and represents a good indicator of cell viability.