Palytoxin toxicity after acute oral administration in mice

The acute oral toxicity of palytoxin (PLTX), a highly toxic compound associated with seafood intoxication in tropical and subtropical areas, was investigated in mice. After gavage administration (300–1697μg/kg) to groups of five female CD-1 mice, signs of toxicity and lethality were recorded for 24h. The LD50 was 767μg/kg (95% confidence limits: 549–1039μg/kg) and the main symptoms observed were scratching, jumping, respiratory distress and paralysis. Hematoclinical analyses showed increased levels of creatine phosphokinase and lactate dehydrogenase at doses of 600μg/kg and above, and aspartate transaminase at 848μg/kg and above. Histological analysis revealed acute inflammation of the forestomach in mice surviving up to 24h after administration (424–1200μg/kg). Other histological alterations were observed in the liver and pancreas, while cardiac and skeletal muscle cells revealed only ultrastructural alterations visible by transmission electron microscopy. Ultrastructural and hematoclinical findings suggest an involvement of skeletal and/or cardiac muscle as targets of PLTX, according to the observed human symptoms. A NOEL of 300μg/kg can be estimated from this acute oral toxicity study.