Can the Apoptosis Kit differentiate between apoptosis and necrosis?
Yes. The kit consists of Annexin-V and Propidium Iodide. Annexin selectively and rapidly binds to phosphatidyl-serine (PS) when PS is translocated from the plasma membrane to the cell surface during apoptosis. The ability to exclude viable dyes, such as propidium-iodide (PI), is a property of cells that have an intact plasma membrane. Living cells or cells in the early phase of apoptosis fall into this category. Necrotic cells have lost membrane integrity and therefore stain with PI, which associates with nuclear DNA. The Annexin V-stained cells, which simultaneously exclude PI molecules from entering the cell, undergo the classic DNA fragmentation pattern found in apoptotic cells. In contrast, cells that undergo necrosis stain with Annexin V and also stain with PI (double positive). Thus, these two populations of cells (necrotic and apoptotic) can be distinguished using this assay.
