title: Uptake, tissue distribution and accumulation of microcystin-RR in Corydoras paleatus, Jenynsia multidentata and Odontesthes bonariensis. A field and laboratory study.
abstract: The uptake and accumulation of microcystin-RR (MC-RR) in fish was investigated under laboratory conditions and in wild fish. Jenynsia multidentata and Corydoras paleatus were exposed for 24h to 50mug/L MC-RR dissolved in water. After exposure, liver, gill, brain, intestine, gall bladder, blood and muscle were analyzed for MC-RR by HPLC and analysis confirmed by LC-ESI-TOF-MS spectrometry. Furthermore, wild individuals of Odontesthes bonariensis were sampled from the eutrophic, cyanobacteria-containing San Roque reservoir, and analyzed for the presence of MC-RR in liver, gill, intestine, and muscle. MC-RR was found in liver, gills, and muscle of all exposed and wild fish, while in C. paleatus MC-RR was also present in the intestine. Moreover, we found presence of MC-RR in brain of J. multidentata. Results indicate that MC-RR uptake might occur at two different organs: intestine and gills, through either feeding (including drinking) or respiratory activities. This suggests that MC-RR is taken into the blood stream after absorption, and distributed to different tissues. The liver showed the major bioaccumulation of MC-RR in both experimentally exposed and wild individuals, with muscle of wild fish showing relative high amounts of this toxin in comparison with those exposed in the laboratory; though MC-RR was present in muscle of fish exposed for 24h. The amount of MC-RR in muscle of O. bonariensis exceeded the value suggested by WHO to be safe, thus causing a health risk to persons consuming fish as a result of chronic exposure to microcystin. Gills also showed bioaccumulation of MC-RR, raising questions on the mechanism involved in the possible uptake of MC-RR through gills as well as on its accumulation in this organ. Although MC-LR has been reported in brain of fish, this is the first report confirming the presence of MC-RR in this organ, which means that both toxins are able to cross the blood-brain barrier. These findings also raise questions on the probable neurotoxicity of microcystins.
authors.affiliation: Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Cátedra Diversidad Animal II, Velez Sarsfield 299, 5000 Córdoba, Argentina.
authors.forename: Jimena
authors.initials: J
authors.lastname: Cazenave
authors.forename: Daniel Alberto
authors.initials: DA
authors.lastname: Wunderlin
authors.forename: María
authors.initials: M
authors.lastname: de Los Angeles Bistoni
authors.forename: María Valeria
authors.initials: MV
authors.lastname: Amé
authors.forename: Eberhard
authors.initials: E
authors.lastname: Krause
authors.forename: Stephan
authors.initials: S
authors.lastname: Pflugmacher
authors.forename: Claudia
authors.initials: C
authors.lastname: Wiegand
mesh_terms: D000818:Animals; D001118:Argentina; D001921:Brain / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005399:Fishes / Q000378:metabolism*; D005618:Fresh Water; D005880:Gills / Q000378:metabolism; D008387:Marine Toxins; D052998:Microcystins; D018482:Muscle, Skeletal / Q000378:metabolism; D010456:Peptides, Cyclic / Q000493:pharmacokinetics*; D021241:Spectrometry, Mass, Electrospray Ionization; D014018:Tissue Distribution; D014781:Viscera / Q000378:metabolism
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; C063855:microcystin RR