Comparison of antihemorrhagic activities in skeletal muscle extracts from various animals against Bothrops jararaca snake venom

The antihemorrhagic factor of the Mexican ground squirrel, (Spermophilus mexicanus)

The Mexican ground squirrel (Spermophilus mexicanus) has a natural resistance to western diamondback rattlesnake venom (Crotalus atrox). The LD50 for the Mexican ground squirrel is 53 mg/kg body weight, which is 13 times higher than that of BALB/c mice. An antihemorrhagic factor from serum of the Mexican ground squirrel was isolated using Sephadex G-200 gel filtration, ion exchange A-50, G-75 gel filtration and HPLC DEAE 5PW ion exchange chromatography. The purified factor neutralized proteolytic and hemorrhagic activity of crude C. atrox venom. The results of this research suggest that the antihemorrhagic factor in the serum of the Mexican ground squirrel is not an antibody and neutralizes hemorrhagic activity of C. atrox venom.

Natural protease inhibitors to hemorrhagins in snake venoms and their potential use in medicine

Snake venoms are complex mixtures of many toxins and enzymes which effectively immobilize prey without a struggle and assist in digestion. Certain animals have a remarkable resistance to envenomation of snakes. Naturally occurring factors that neutralize snake venoms have been found in the sera of most snakes and a few warm-blooded animals. These antihemorrhagic and antineurotoxic factors have been purified from snake and mammalian sera. The antihemorrhagins are not immunoglobulins since they have different physical and chemical characteristics. The natural immunity to hemorrhagins is the result of tissue inhibitors of metalloproteinases (TIMP) found in animal sera of resistant animals. Most animals have matrix metalloproteinases (MMP) and TIMP that are implicated in a wide variety of normal physiological processes and pathological conditions. MMP in animals have many biological functions in embryogenesis, morphogenesis and tissue remodeling. MMP activities are precisely regulated by endogenous TIMP. Disruption of the balance between MMP and TIMP causes various diseases such as arthritis, periodontal diseases, diabetes, ophthalmologic conditions, neoplasia, metabolic bone disease, atherosclerosis and orthopedic conditions. Resistant animals that have a high titer of TIMP would have a survival advantage when bitten by poisonous snakes. Snake venoms are abundant and stable sources of MMP which are medically important. The venom MMP which cause unregulated destruction of tissue have sequences which have some degree of homology with mammalian MMP which control normal biological processes. Resistant animals are important sources of TIMP which can be used to study metalloproteinase related diseases. For these reasons the MMP in snakes and TIMP in resistant animal are excellent candidates for developing new drug therapies.