Irreversible condensation of chromatin in the nucleus of a dying cell
ApoptosisMorphological characteristics of pyknosis and other forms of nuclear destruction
Pyknosis, or karyopyknosis, is the irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis[1] or apoptosis.[2] It is followed by karyorrhexis, or fragmentation of the nucleus.
Pyknosis (from Ancient Greek πυκνός meaning "thick, closed or condensed") is also observed in the maturation of erythrocytes (a red blood cell) and the neutrophil (a type of white blood cell). The maturing metarubricyte (a stage in RBC maturation) will condense its nucleus before expelling it to become a reticulocyte. The maturing neutrophil will condense its nucleus into several connected lobes that stay in the cell until the end of its cell life.
Micrograph of an infarct in the biliary tract, with pyknotic nuclei (arrows) (400x).
Pyknotic nuclei are often found in the zona reticularis of the adrenal gland. They are also found in the keratinocytes of the outermost layer in parakeratinised epithelium.
^Kumar V, Abbas A, Nelson F, Mitchell R (2007). Robbins Basic Pathology (8th ed.). pp. 6, 9–10 (table 1-1).
^Kroemer G, Galluzzi L, Vandenabeele P, Abrams J, Alnemri ES, Baehrecke EH, et al. (January 2009). "Classification of cell death: recommendations of the Nomenclature Committee on Cell Death 2009". Cell Death and Differentiation. 16 (1): 3–11. doi:10.1038/cdd.2008.150. PMC 2744427. PMID 18846107.
Pyknosis, or karyopyknosis, is the irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis or apoptosis. It is followed by...
distributed irregularly throughout the cytoplasm. It is usually preceded by pyknosis and can occur as a result of either programmed cell death (apoptosis),...
occurs. Affected cells then proceed to blebbing, and this is followed by pyknosis, in which nuclear shrinkage transpires. In the final step of this pathway...
usually dissolves into apoptotic bodies. Disintegration of the cytoplasm, pyknosis of the nuclei, and karyolysis of the nuclei of scattered transitional cells...
they are most susceptible to hypoxic injury. The red coloration is due to pyknosis or degradation of the nucleus and loss of Nissl bodies which are normally...
breakdown leading to cell death. The stages of cellular necrosis include pyknosis, the clumping of chromosomes and shrinking of the nucleus of the cell;...
This causes acidosis, osmotic shock, clumping of chromatin and nuclear pyknosis. These changes are accompanied by a loss of oxidative phosphorylation,...
until about 24 to 72 hours after hypoxia. ON is first characterized by pyknosis of nuclei, followed by hollow osteocyte lacunae. Capillary revascularization...
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Micrograph of an infarct in the biliary tract, with pyknotic nuclei (arrows) (400x).