Pathophysiology of sea nettle (Chrysaora quinquecirrha), envenomation in a rat model and the effects of hyperbaric oxygen and verapamil treatment.

The effect of lethal sea nettle envenomation on the morphology and blood flow in various rat organs was characterized and the influence of two antidotes (hyperbaric oxygen and verapamil) was compared. Either antidote slightly prolonged survival, but the protective effects were not statistically significant. The venom caused no histologic alterations in brain, heart, or lungs but induced hepatic and renal necrosis. Hepatocytes in mid-zonal regions and renal tubular epithelium were the cell types predominantly affected. Hyperbaric oxygen and verapamil did not decrease the hepatic injury. The venom did not influence central hemodynamics until preterminally and it diminished blood flow to brain, but not to liver or kidney. Hyperbaric oxygenation protected against venom-induced decreases in blood flow to the brain. These results add toxic hepatic and renal necrosis and cerebral ischemia to the pathophysiology of envenomation in this model.