Ciguatoxins (CTX) -Ciguatera: mouse bioassay test

Version 8.8.2013.

Ciguatoxin, a set of marine biotoxins liposoluble are produced by unicellular algae, which are concentrated through a food chain in fish. The apparently healthy human intake of fish carriers called ciguatera poisoning causes (ictiosarcotoxismo). There are several methods for detecting the presence of ciguatoxin, although none of them meets the requirements of speed and simplicity required for rapid detection. The main methods used are: a) in vivo bioassay methods, using different animals such as mice, cats, chickens, mongooses, mosquitoes, shrimp, maggots, ... .., which consist of feeding or inoculating with concentrated extracts prepared from fish meat; b) method LCMS (liquid chromatography mass spectrometry, with different variants; c) other methods: immunological (radioimmunoassay, ELISAs various formats); binding to cellular sodium channels with neuroblastoma cell cultures; tests with isolated tissues (guinea pig atria isolated nerve, erythrocyte hemolysis), etc. Each of these methods has its advantages and disadvantages in terms of speed, sensitivity, or different types of toxins detected.

In our laboratory we perform the mouse bioassay method, inoculating several batches of five mice with a concentrated extract. This method has the drawback of being slow, requiring prepare the concentrated extract inoculation and subsequent observation for several days, batches of mice inoculated with different dilutions of the extract, to calculate the 50% lethal dose.