Oxidative stress and apoptosis

Overview

Apoptosis is a form of cell death in which an individual cell undergoes an internally controlled transition from an intact metabolically active state into a number of shrunken remnants retaining their membrane bound integrity (Kerr et al., 1972; Wyllie et al., 1980). Lysis of internal organelles such as lysosomes and mitochondria does not occur during this process, and little external leakage of the contents of the dying cell can be detected. As a consequence, apoptotic cells do not induce an inflammatory response in vivo. Instead the shrunken apoptotic bodies are avidly phagocytosed by macrophages and their contents recycled (Savill et al., 1993). Apoptosis therefore provides the organism with a safe and efficient way to continuously turn over cells in any tissue and the capability to selectively delete specific cells during development. It is distinct from necrotic cell death, in which an entire population of cells exposed to a suitable toxin undergo internal dissolution and eventual lysis, resulting in vivo in the recruitment of inflammatory cells into the necrotic tissue.