title: Time-dependent protective efficacy of Trolox (vitamin E analog) against microcystin-induced toxicity in tilapia (Oreochromis niloticus).
abstract: Microcystins (MCs), hepatotoxins from cyanobacteria, induce oxidative stress and pathological changes in fish that can be ameliorated with chemoprotectants such as vitamin E (vit E). This study investigated the time period after MCs exposure in which Trolox, a vitamin E analog, is effective against oxidative and histological damage in different organs of tilapia (Oreochromis niloticus). Fish were fed Trolox supplement (700 mg/kg diet) for 7 days, or received only commercial fish food, and then were exposed to a single oral dose of 120 microg/fish microcystin-LR, and sacrificed in 24, 48, or 72 h. The Trolox protective efficacy was evaluated based on lipid peroxidation (LPO), protein oxidation, enzymatic and non-enzymatic antioxidants, and a morphologic study. Regarding the oxidative stress biomarkers altered by MCs, the higher protective action of Trolox was observed 24 h post toxin exposure, although it extends also until 48 h in gills (superoxide dismutase (SOD), catalase (CAT)), and liver, where glutathione reductase (GR) backed to control values 48 and 72 h after the toxin application. Glutathione-S- transferase (GST) activity in the liver was ameliorated by the chemoprotectant after 24 and 48 h, although control values were not recovered. Trolox modulation of these biomarkers and its ability to quench free radicals explain the recovery of LPO values in all organs at 24 h and also in gills at 48 h. Histopathologically, Trolox efficacy was more evident after 72 h.
authors.affiliation: Area of Toxicology, Faculty of Pharmacy, University of Seville, Spain.
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Prieto
authors.forename: Angeles
authors.initials: A
authors.lastname: Jos
authors.forename: Silvia
authors.initials: S
authors.lastname: Pichardo
authors.forename: Isabel
authors.initials: I
authors.lastname: Moreno
authors.forename: María Alvarez
authors.initials: MA
authors.lastname: de Sotomayor
authors.forename: Rosario
authors.initials: R
authors.lastname: Moyano
authors.forename: Alfonso
authors.initials: A
authors.lastname: Blanco
authors.forename: Ana María
authors.initials: AM
authors.lastname: Cameán
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D002839:Chromans / Q000494:pharmacology*; D005880:Gills / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000378:metabolism; D052998:Microcystins / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism; D017210:Tilapia / Q000378:metabolism*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000975:Antioxidants; D001427:Bacterial Toxins; D002839:Chromans; D052998:Microcystins; C078588:microcystin; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid