title: Pathological modifications following sub-chronic exposure of medaka fish (Oryzias latipes) to microcystin-LR.
abstract: Microcystins (MCs) are toxic monocyclic heptapeptides produced by many cyanobacteria. MCs, especially MC-LR, cause toxic effects in animals and are a recognized potent cause of environmental stress and health hazard in aquatic ecosystems when heavy blooms of cyanobacteria appear. Consequently, one of the major problems is the chronic exposure of fish to cyanotoxins in their natural environment. The present experiment involving chronic exposure confirmed initial findings on acute exposure to MC contamination: exacerbated physiological stress and tissue damage in several tissues of exposed medaka fish. The gonads were affected specifically. In female gonads the modifications included reduction of the vitellus storage, lysis of the gonadosomatic tissue and disruption of the relationships between the follicular cells and the oocytes. In the males, spermatogenesis appeared to be disrupted. This is the first report showing that a cyanotoxin can affect reproductive function, and so can impact on fish reproduction and thus fish stocks.
authors.affiliation: UMR 7245 CNRS-USM 0505 Molécules de Communication et Adaptation des Micro-Organismes, Muséum National d'Histoire Naturelle, 12 rue Buffon, F-75231 Paris cedex 05, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Trinchet
authors.forename: Chakib
authors.initials: C
authors.lastname: Djediat
authors.forename: Hélène
authors.initials: H
authors.lastname: Huet
authors.forename: Simone Puiseux
authors.initials: SP
authors.lastname: Dao
authors.forename: Marc
authors.initials: M
authors.lastname: Edery
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D000458:Cyanobacteria; D005260:Female; D007422:Intestines / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D008099:Liver / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D008387:Marine Toxins / Q000633:toxicity*; D052998:Microcystins / Q000633:toxicity*; D046529:Microscopy, Electron, Transmission; D009990:Oryzias; D010053:Ovary / Q000187:drug effects / Q000473:pathology; D013091:Spermatogenesis / Q000187:drug effects; D013154:Spleen / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D013737:Testis / Q000187:drug effects / Q000473:pathology
chemical_list: D001427:Bacterial Toxins; D008387:Marine Toxins; D052998:Microcystins; C057862:cyanoginosin LR