Differences between Apoptosis and Necrosis
Apoptosis vs. Necrosis[edit]
Apoptosis and necrosis are two distinct forms of cell death. Apoptosis is a regulated, programmed process of cell death, often referred to as cellular suicide, that is essential for normal physiological functions.[1][2] In contrast, necrosis is an unregulated form of cell death that occurs as a result of acute injury or disease.[3][4] While apoptosis is a controlled process that does not trigger an inflammatory response, necrosis involves the rupture of the cell membrane, which releases intracellular contents and can lead to inflammation.[5][3]
Apoptosis plays a crucial role in tissue development, homeostasis, and the removal of damaged cells.[1] The process is characterized by specific morphological changes, including cell shrinkage, chromatin condensation, and the formation of apoptotic bodies. These bodies are then engulfed by phagocytic cells, preventing inflammation. The apoptotic process can be initiated through two main pathways: the intrinsic pathway, which is triggered by internal cellular stress such as DNA damage, and the extrinsic pathway, which is activated by external signals from other cells. Both pathways converge on the activation of caspases, a family of proteases that execute the process of cell death.
Necrosis, on the other hand, is a passive and often violent form of cell death resulting from external factors like trauma, infection, or toxins.[3] Morphologically, necrosis is characterized by cell swelling, rupture of the plasma membrane, and the breakdown of organelles. The release of cellular contents into the surrounding tissue typically induces an inflammatory response.[5] There are several distinct morphological patterns of necrosis, including coagulative, liquefactive, caseous, fat, and gangrenous necrosis, each associated with different types of tissue injury. For instance, coagulative necrosis is often seen in hypoxic tissues, while liquefactive necrosis is common in the brain and in bacterial infections.
Recently, a regulated form of necrosis called necroptosis has been identified. This process shares features with both apoptosis and necrosis and is activated when the apoptotic pathway is inhibited.
Comparison Table[edit]
| Category | Apoptosis | Necrosis |
|---|---|---|
| Definition | Programmed and regulated cell death.[1] | Unregulated cell death due to injury or disease.[3][4] |
| Triggers | Initiated by physiological or pathological stimuli, through intrinsic or extrinsic pathways. | Caused by external factors such as trauma, infection, toxins, or ischemia.[3] |
| Cellular Morphology | Cell shrinkage, membrane blebbing, chromatin condensation, and formation of apoptotic bodies. | Cell swelling, organelle disruption, and rupture of the plasma membrane. |
| Biochemical Processes | ATP-dependent process involving the activation of caspases. | Generally ATP-independent, characterized by loss of ion homeostasis and enzymatic digestion of cellular components. |
| DNA Fragmentation | Orderly cleavage of DNA into specific fragments. | Random and diffuse degradation of DNA. |
| Plasma Membrane | Remains intact until the final stages, with the formation of apoptotic bodies. | Early loss of integrity and rupture, leading to the release of cellular contents.[3] |
| Inflammatory Response | Typically non-inflammatory as cellular debris is cleared by phagocytes.[5] | Induces an inflammatory response due to the release of intracellular contents.[5][3] |
| Physiological Role | Essential for normal development, tissue homeostasis, and removal of damaged cells.[1] | Generally pathological and detrimental to the organism.[3] |
References[edit]
- ↑ 1.0 1.1 1.2 1.3 "nih.gov". Retrieved February 04, 2026.
- ↑ "physiology.org". Retrieved February 04, 2026.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 "wikipedia.org". Retrieved February 04, 2026.
- ↑ 4.0 4.1 "mdpi.com". Retrieved February 04, 2026.
- ↑ 5.0 5.1 5.2 5.3 "researchgate.net". Retrieved February 04, 2026.
