ISOLATION OF MYOTOXIC COMPONENT FROM RATTLESNAKE (CROTALUS-VIRIDIS-VIRIDIS) VENOM - ELECTRON-MICROSCOPIC ANALYSIS OF MUSCLE DAMAGE

Abstract

The pathogenesis of myonecrosis induced by a purified component of rattlesnake (C. v. viridis) venom was studied at the light and electron microscopic levels. Crude venom was fractionated by gel filtration (Sephadex G-50) followed by cation exchange chromatography (Sephadex C-25). Electrophoretic homogeneity of the isolated myotoxin (Fraction II from C-25 column) was demonstrated in isoelectric focusing and disc gel polyacrylamide gel electrophoresis. White mice were injected i.m. with 1.5 .mu.g/g of the purified protein in 0.1 ml of physiologic saline. Light microscopic examination of injected muscle revealed a series of degenerative events including partial vacuolation of muscle cells at 6, 12 and 24 h and complete vacuolation and loss of striations at 48 and 72 h. Hemorrhage was not observed. At the EM level the perinuclear space and sarcoplasmic reticulum were dilatated in all samples. By 48 and 72 h the myofibrils lacked striations and the sarcomeres were disorganized. Plasma membranes and T [transverse] tubules remained intact in all samples. These resulted correlated well with the myonecrosis induced by crude C. v. viridis venom except for several important aspects. The pure component altered skeletal muscle cells specifically, with the sarcoplasmic reticulum being the primary site of action.