Palytoxin toxicity after acute oral administration in mice

Abstract 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 (300–1697 μg/kg) to groups of five female CD-1 mice, signs of toxicity and lethality were recorded for 24 h. The LD 50 was 767 μg/kg (95% confidence limits: 549–1039 μg/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 600 μg/kg and above, and aspartate transaminase at 848 μg/kg and above. Histological analysis revealed acute inflammation of the forestomach in mice surviving up to 24 h after administration (424–1200 μg/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 300 μg/kg can be estimated from this acute oral toxicity study.