Necrosis of cells is a pathological form of cell death, occurs when a virus or infection multiplies, destroys it. Upon destruction, the contents of the cell pour into the intercellular space, and the microbes enter neighboring cells, the inflammatory process begins and the entire organism is harmed. Necrotic cell death can be caused by physical, chemical, biological, allergic, vascular, trophoneurotic lesions.
Necrosis is characterized by passive degeneration of cells with swelling and fragmentation of organelles. Invariably, this pathology is accompanied by destruction of membranes and destruction of cells. Destructive processes in the cell release intracellular contents into the surrounding tissue, this threatens the development of inflammatory processes.
This pathology possesses mechanisms that do not require expenditure of energy, its prevention is possible only if the causes of the occurrence are eliminated. Cells die during necrosis from changes in the membrane or cytoplasm of cells, the cell nucleus becomes smaller in volume, wrinkled, dense, dark blue with hematoxylin.
Capture the cell with complement, causes porosity of the membrane, disturbance of osmotic pressure in the cell, rupture of the membrane and leads to cell death. Inflammation to surrounding cells is a catastrophe and ultimately disrupted by various functions that are life threatening.
Approximately 5 hours after the cell death, its cytoplasm becomes homogeneous and expressed by acidophilus, because coagulation of cytoplasmic proteins and destruction of ribosomes occur. First of all, specialized cell organelles, such as myofibrils in myocardial cells, disappear.
The changes in the intercellular substance can also be irreversible. They encompass interstitial substance and fibrous structures. Most often collagen, elastic and reticulin fibers undergo fragmentation, deep disintegration or lysis, turning into dense, homogeneous, sometimes colorless masses. Rarely there is swelling and mucosal fibroid structures.
Outcomes of necrosis of cells are different, it all depends on the type of tissue and the degree of damage. Possible replacement by healthy cells as a result of their reparative regeneration. In many cases, there is a demarcation inflammation and proliferation of connective tissue with the replacement of necrotic structures in the form of a scar.
The development of necrosis can lead to purulent melting, sequestration, i.e., separation of the focus from intact tissues. A dense capsule can form around the necrotic tissues or necrotic structures can be impregnated with phosphoric-calcium salts. Treatment of cell necrosis often ends with recanalization, resulting in the germination of dead tissue with newly formed vessels. It is necessary to know that the death of a cell is a constant manifestation of the vital activity of the organism. But as a result of external damaging factors, cell death is accompanied by irreversible biochemical and structural changes. There are two stages of cell necrosis:
paranecrosis – a reversible state of the cell close to death;
; necrobiosis (cell disease) is an irreversible process of extinction; Changes in tissues with necrosis damage are divided into two groups:
· colliquated necrosis is manifested by dissolution of the nucleus (karyolysis) and cytoplasm (cytolysis),
· coagulation necrosis is characterized by chromatin condensation, nuclear disintegration and simultaneous coagulation of the cytoplasm. This type of necrosis affects cells poor in proteins, as it is known that proteins perform construction function (anabolic process). When the proteins are cleaved, energy is released and a catabolic process occurs.
Modern research in the search for methods of treating cell necrosis, give positive results. So, since recently, a method of therapy has been used that allows the use of stem cells. The method consists in the possibility of using its own bone marrow cell concentrate for treatment damaged by tissue disease. Stem cells have an amazing ability to degenerate into any kind of cell.
Extraction of stem cells is carried out for the treatment of bone necrosis, with necrosis of the femoral head, joint wear, incurable bone fractures and necrosis of the tendons and muscles.
There is another kind of cell death – apoptosis. This is the physiological death of cells, based on the division of the cell into parts, not accompanied by the development of the inflammatory process. Apoptosis occurs constantly, cells undergo aging and their subsequent destruction. The difference between apoptosis and necrosis is that it affects individual cells or groups of cells.