Myotoxicity
Snake envenomation induces prominent local tissue damage that
often results in permanent disability and systemic alterations
associated with haemorrhage, coagulopathies, cardiovascular shock
and renal failure. Clinical reports indicate that, in humans, the main
invalidating effect is the irreversible disruption of muscle tissue [91].
Tissue necrosis is a relevant local effect caused after snakebites, it is
considered as a serious consequence in severe cases of envenomation.
When myonecrosis appears tissues are altered leading to the gangrene
and infections. This type of complication can be the cause of
amputation. Indeed, myotoxins of snake venoms affect mainly the
plasma membrane of muscle cells to which they bind through their
cationic sequence [73,92]. Molecular mechanism by which they caused
the muscle tissue damage is not yet fully elucidated. Myonecrosis is
due to the myotoxins that induce irreversible damage of skeletal
muscle fibers. These molecules bind to the plasma membrane of
muscle cells and alter its permeability and integrity (Figure 4). The
induced muscle tissue damage could be due to the penetration of
myotoxins into muscle cells by endocytosis, probably through
membrane receptors onto the surface of muscle cells or following
hydrolysis of phospholipids causing membrane disruption. These
molecules enter into the cytosol, reach and alter the membrane of
mitochondria and sarcoplasmic reticulum of muscle cells. The
intracellular effect of these toxins occurs only after their initial action
on the plasma membrane, which marks the onset of degenerative
events [93,94].