Histopathological and biochemical alterations induced by intramuscular injection of Bothrops asper (terciopelo) venom in mice.

The local and systemic pathological changes induced by an i.m. injection of 100 micrograms of Bothrops asper venom in mice were studied histologically and by following the changes in serum levels of enzymes, proteins, ATP and lactate, as well as alterations in hematocrit and clotting time. B. asper venom induced a rapid and marked increase in serum levels of creatine kinase, aspartate aminotransferase and lactate dehydrogenase, but not alanine aminotransferase or alkaline phosphatase. A local myonecrosis and hemorrhage was observed, with the lungs collapsing by 24 hr and the kidneys showing glomerular congestion and vacuolar degeneration of tubular cells. Only minor histopathological changes were observed in cardiac muscle and liver. Both ATP and lactate blood levels decreased after venom injection, whereas there were no changes in serum protein concentration. Blood incoagulability was observed 1 and 3 hr after envenomation. Antivenom neutralized venom-induced increases in serum enzyme levels following preincubation with venom, indicating that antivenom contains antibodies against tissue-damaging toxins. However, when antivenom was administered i.v. at different time intervals after venom injection, neutralization was only partial, with the exception of defibrinating activity, which was totally neutralized even after a delay of 1 hr in administering antivenom.