- Necrosis is one of the basic patterns of irreversible cell injury and death. Necrosis has long been considered the "unregulated" pattern of cell injury and death, representing a messy end to a damaged cell that consequently causes a potent inflammatory response. However, very recent work is pointing to some regulated aspects of Necrosis and thus our understanding of this form of cell death is likely to undergo significant revision in the future.
- The basic morphological theme of Necrosis is the enzymatic degradation and denaturation of cellular molecules, particularly proteins. Denaturation refers to loss of the fine-tuned structural conformation of biological molecules and their pathological conversion to any non-functional structural conformation. Protein denaturation results in exposure of hydrophobic regions normally sequestered within the three-dimensional center of the molecules and may explain why necrotic cells display an increased capacity to bind the hydrophobic Eosin pigment (Eosinophilia). Additionally, degradation of cytosolic RNA, which is normally basophilic, may contribute to the increased cellular Eosinophilia seen in necrosis. The nuclei of necrotic cells also display significant changes and may undergo total fading (karyolysis), shrinkage (pyknosis), or fragmentation (karyorrhexis). Although all necrotic cells share these features, several morphological sub-categories have been identified which correspond to particular etiologies of cellular injury.