A comparative electron microscopic study of myonecrosis induced by Crotalus atrox (Western diamondback rattlesnake) in gray woodrats and mice.

The myonecrosis induced by Western diamondback rattlesnake (Crotalus atrox) venom in the woodrat (Neotoma micropus) was studied at the electron microscopic level. Woodrats and control white mice were injected i.m. with 0.1 ml of diluted venom. Gross examination revealed extensive hemorrhage when 250 micrograms were injected into mice. Electron microscopic examination showed muscle necrosis in mouse muscle tissue. No extensive hemorrhage or muscle damage was noted until 7.5 and 15 mg of venom were injected i.m. into woodrats. The most prominent damage was swollen mitochondria and destruction of the myofibrils for both mice and woodrats. These results clearly indicate that woodrats are more resistant to the myotoxins in rattlesnake venom than white mice.