Oxidative stress in toadﬁsh (Halobactrachus didactylus) cardiac muscle Acute exposure to vanadate oligomers

Aureliano, M.

http://hdl.handle.net/10400.1/4814

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Aureliano, M.

Abstract(s)

Vanadate solutions as ‘metavanadate’ (containing ortho and metavanadate species) and ‘decavanadate’ (containing manly 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 (123%) upon decavanadate administration. After 7 days of exposure, decavanadate versus metavanadate solutions promoted different effects mainly on cytosolic CAT activity (256% versus25%), mitochondrial CAT activity (210% versus110%) and total GPx activity (11% versus235%), whereas lipid peroxidation products were signiﬁcantly increased (182%) upon 500mM decavanadate intoxication. Accumulation of vanadium in total (0.13760.011mg/g) and mitochondrial (0.02260.001mg/g) fractions was observed upon 7 days of metavanadate exposure, whereas for decavanadate, the concentration of vanadium increased in cytosolic (0.02060.005mg/g) and mitochondrial (0.02160.009mg/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.