Sub-lethal dosing of azaspiracid-1 in female NMRI mice.

The main aim of this study was to examine absorption and pathological effects of a single sub-lethal dose of the marine biotoxin azaspiracid-1 (AZA1) in mice after oral intubation. When the mice received AZA1 at doses of 100, 200 or 300 μg/kg body weight (b.w.), the toxin was absorbed dose-dependently. Highest concentrations after 24 h were detected in kidneys, spleen and lungs, followed by liver and heart. Only trace amounts were seen in the brain. After seven days, the toxin level had dropped significantly in all organs except for the kidneys. The amount of toxin absorbed was highest in the liver, followed by kidneys, lungs, spleen and heart and the total amount of toxin in the internal organs analysed after 24 h was estimated to be only about 2% of the total amount given for all three dose groups. Pathological changes were only detected in the upper part of the small intestine (duodenum), consisting of mild cellular detachment in the tips of the villi, expansion of the crypts and necrotic changes in lamina propria. In a previous study very long persistence of damage to the gastrointestinal tract by repeated exposures to AZA toxins was reported. In our study, full recovery from the pathological changes was observed seven days after a single exposure to AZA1 at the doses applied.