Marine toxin C17-SAMT causes major structural damage to vital organs in mice following subchronic toxicity trials

Abstract

C17-sphinganine analog mycotoxin (C17-SAMT) has been characterized as the contaminant responsible for the atypical toxicity reported in mussels from the Bizerte lagoon (northern Tunisia) over the past decade. C17-SAMT exhibited common symptoms of toxicity in mice, including flaccid paralysis and severe respiratory distress, followed by rapid death. To determine the potential health risks of this neurotoxin, we assessed its subchronic toxicity according to the recommendations of OCDE n° 407. The body weight and the structural changes of vital organs were recorded. Biochemical and hematological parameters were also quantified. Macroscopic observations showed that mice treated with 0.9, 9, and 90 µg/kg C17-SAMT had significantly reduced stomach weights, swollen and fragile intestines, and signs of nephritis with renal abscesses. Transaminase assays pointed out that exposure to C17-SAMT can lead to transaminitis. Above-average lactate dehydrogenase values were recorded in both the treated and satellite groups. Hematology data showed a significant reduction in red blood cell counts in high-dose-treated group. Reductions in hemoglobin and hematocrit were also recorded. Mean leukocyte counts were significantly elevated in the high-, mid-dose treated and satellite groups. At the microscopic level, we noted myocardial atrophy and hyperemia. In the lungs, we noted necrosis associated with macrophages perivascular infiltration and congestion. The kidneys showed mild inflammation and glomerular atrophy. The stomach exhibited mucosal atrophy, while a thin colon and distended small intestine were observed in high-dose-treated group. The liver was affected by vascular congestion, inflammatory infiltration, and lobular necrosis that evolved into acute hepatitis. Lesions, such as inflammatory infiltration and mild necrosis of the liver, cortical abscess with central necrosis in the kidney, and mild congestion of cardiac tissue were recorded in the satellite group.

Keywords: Atrophy; C17-SAMT; Congestion; Hepatitis; Inflammation; Marine toxin; Necrosis; Subchronic toxicity.