Oxidative stress in toadfish (Halobactrachus didactylus) cardiac muscle. Acute exposure to vanadate oligomers.
Vanadate solutions as "metavanadate" (containing ortho and metavanadate species) and "decavanadate" (containing mainly decameric species) (5 mM; 1 mg/kg) were injected intraperitoneously in Halobatrachus didactylus (toadfish), in order to evaluate the contribution of decameric vanadate species to vanadium (V) intoxication on the cardiac tissue. Following short-term exposure (1 and 7 days), different changes on antioxidant enzyme activities-superoxide dismutase (SOD), catalase (CAT), selenium-glutathione peroxidase (Se-GPx), total glutathione peroxidase (GPx), lipid peroxidation and subcellular vanadium distribution were observed in mitochondrial and cytosolic fractions of heart ventricle toadfish. After 1 day of vanadium intoxication, SOD, CAT and Se-GPx activities were decreased up to 25%, by both vanadate solutions, except mitochondrial CAT activity that increased (+23%) upon decavanadate administration. After 7 days of exposure, decavanadate versus metavanadate solutions promoted different effects mainly on cytosolic CAT activity (-56% versus -5%), mitochondrial CAT activity (-10% versus +10%) and total GPx activity (+1% versus -35%), whereas lipid peroxidation products were significantly increased (+82%) upon 500 microM decavanadate intoxication. Accumulation of vanadium in total (0.137+/-0.011 microg/g) and mitochondrial (0.022+/-0.001 microg/g) fractions was observed upon 7 days of metavanadate exposure, whereas for decavanadate, the concentration of vanadium increased in cytosolic (0.020+/-0.005 microg/g) and mitochondrial (0.021+/-0.009 microg/g) fractions. It is concluded that decameric vanadate species are responsible for a strong increase on lipid peroxidation and a decrease in cytosolic catalase activity thus contributing to oxidative stress responses upon vanadate intoxication, in the toadfish heart.
Aureliano
M
M
CMQA, A.D. Química, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 8000-117 Faro, Portugal. maalves@ualg.pt
Joaquim
N
N
Sousa
A
A
Martins
H
H
Coucelo
J M
JM
D000818:Animals; D024541:Batrachoidiformes / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D006321:Heart / Q000187:drug effects*; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism; D014638:Vanadates / Q000633:toxicity*
D014638:Vanadates; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase