The rock rattlesnakes Crotalus lepidus comprise a group (lepidus, klauberi, morulus and maculosus) of poorly known mountain cold-tolerant snakes in Mexico. In particular, Crotalus lepidus morulus is a snake endemic of the northeast of Mexico, whereas Crotalus lepidus klauberi and C. l. lepidus are distributed in some regions of the north and central Mexico and southern U. S. Until now very little data are available from C. lepidus subspecies from Mexico, as the terrain inhabited by these snakes is generally steep and rugged. In this work, we have determined some biochemical and
biological properties of C. l. morulus, C. l. klauberi and C. l. lepidus crude
venoms. Some minor differences in
venoms were noted in SDS-PAGE, HPLC profile and MALDI-TOF mass spectrometry analysis. Partial sequences of
metalloproteinases,
phospholipases A₂ (PLA₂) and
galactose-specific
lectins were identified in the
venoms.
Venoms of C. l. klauberi and C. l. lepidus had significantly higher hemorrhagic and lethal activities than C. l. morulus
venom. Proteolytic activity in
azocasein was higher in C. l. morulus
venom, whereas
gelatin hydrolysis was higher in C. l. klauberi. Fibrinogenolytic and PLA₂ activities were very similar in all
venoms tested. The histological observations in the gastrocnemius muscle damaged by
venoms from all the subspecies confirmed myonecrotic and hemorrhagic activities (at 3 and 24 h), which resulted in a poor regenerative response after 14 days. However, C. l. lepidus and C. l. klauberi
venom induced a higher increase in the plasma activity of
creatine kinase (CK), evidencing higher
myotoxicity, whereas paw
edema-inducing activity was higher in C. l. lepidus
venom. The results indicate that the
venoms from the three subspecies have similar
protein profiles in electrophoresis, HPLC and molecular weight determinations. However, differences were found in the
biological activities in mice. Notably, the
venoms of C. l. lepidus and C. l. klauberi present higher toxicity (lower LD₅₀) and hemorrhagic activity than C. l. morulus
venom.