To observe the cardiotoxic effects on the mechanism of circulatory shock in acute venom intoxication,´ a biochemical and histopathological studies were carried out in the heart of rats using venom of Agkistyodon caliginosus. The rats used were adults weighing between 200-x250 mg. 32 gm of freeze dried venom was diluted to 12 ml in normal saline, and 0. 4 mi of this solution was administered intravenously through the tail vein to each rat.
The rats were sacrificed serially with time interval; after venom administration I hour, 3 hours, 6 hours, 24 hours 4 days and days, respectively. The hearts were immediately prepared for light and electron microscopy. Additionally, serum enzymes such as glutamic oxaloacetic transaminase (GOT) , lactic dehydrogenase (LDH) and creatinine phosphokinase (CPK) were measures for the correlation.
The results obtained were as follows:
1. Serum levels of GOT were significantly elevated in hours to 298. 0-`219. 6 IU/1 (p<0.05) until 6 hours
2. Serum levels of LDH were significantly reduced from 6 hours and lowest in 24 hours to 340.6+132.7 IU/1 (p<0.01) until 4 days.
3. Serum levels of CPK were significantly reduced in 24 hours 543.4--469.4IU/1 (p<0.05).
4. Light microscopic changes in the heart revealed moderate to marked congestion, edema, hemorrhage in the ventricular and subendocardial myocardium with coagulation necrosis of myocardial muscles in the hemorrhagic areas in 1 hour after venom administration. Infiltration of inflammatory cells were increased in 3-,-6 hours. Later, fibrosis was due in the multiple areas of previous necrosis.
5. Early electronmicroscopic changes in the myocardium revealed marked intracellular edema with lifting, bleb formation and rupture of sarcolemma as well as separation of myofilaments and focal random loss of myofilaments, vlitochondrial swelling and vacuolar changes -,very also noted.
With above results, it was assumed that cardiotoxocity of venom of Agkistrodon caliginosus, characterized by marked myocardial edema and hemorrhage with necrosis could play a role in explaining acute circulatory collapse in rats after venom intoxication. It was also interesting to note that the extent of myocardial damage did not correlated with the levels of serum GOT, LDH, and CPI.
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