Haemoperfusion treatment in pigs experimentally intoxicated by paraquat

Abstract

1 Because of their similarity in renal morphology and physiology to humans, domestic pigs (gilts, 70 kg) were bolus treated by intramuscular injection of 74,17, and 6 mg kg^-1 and by oral loading (70 mg kg^-1 n=4) of paraquat. The concentration peak of plasma paraquat was reached at 1.5 - 2.5 h. Renal clearance of paraquat rose to its maximum at 5 - 6 h after intoxication and then sharply decreased indicating renal failure. All the intoxicated pigs died.

2 An additional 10 gilts were also orally treated with 70 mg kg^-1 paraquat but received haemoperfusion from 2 h post intoxication for either 2 h (n=6) or 6 h (n=4). The 2 h haemoperfusion resulted in a 5.1% toxin removal but failed to save any of six poisoned pigs. Prolonged 6 h haemoperfusion successfully rescued three out of four intoxicated pigs.

3 The plasma paraquat concentrations of the three surviving pigs were above 2 mg l ^-1 at 10 h post intoxication. This level is not only similar to those of untreated animals that died later, but also well beyond the suggested limit for survival of poisoned patients.

4 Pigs proved to be a good animal model for studies in paraquat poisoning and/or haemoperfusion. It is also suggested that early haemoperfusion is effective in treating paraquat poisoning even in very severe cases due to its possible detoxicating effect in addition to toxin removal.