Detection of molecular events during apoptosis by flow cytometry

Apoptosis describes an intrinsic cell suicide program that may be activated by both endogenous and exogenous stimuli. This method of cell death is characterized by specific morphological features including chromatin condensation, nuclear fragmentation, cell shrinkage, membrane blebbing, and the formation of membrane-bound vesicles termed apoptotic bodies (1). Apoptosis has come to be referred to as the physiological mode of cell death, as it allows cellular destruction in the absence of an associated inflammatory response. In contrast, necrosis is a pathological mode of cell death that occurs under circumstances of severe cellular injury/trauma. Necrotic cell death involves cell swelling and organelle disruption, followed by lysis and release of cellular debris. This form of cell death may cause damage to surrounding tissue due to the inappropriate triggering of an inflammatory response (2).