Alterations in Antioxidant Status of Erythrocytes of African Catfish (Clarias gariepinus) Exposed to Cypermethrin: A Possible Involvement of Free Radicals
Abstract
Different concentrations of cypermethrin have been reported to induce oxidative stress due to generation of free radicals and alteration in antioxidant defense mechanisms. Clarias gariepinus was exposed to various
concentrations (0, 5, 10, 15 and 20) μg/L of cypermethrin in dechlorinated water. The most outstanding results of this study were found for superoxide dismutase (SOD) and acetylcholinesterase (AChE) activities in erythrocyte and erythrocyte membrane respectively. Cypermethrin resulted in decreased erythrocyte glucose-6-phosphate dehydrogenase (G6PDH), glutathione peroxidase (GPx) and catalase (CAT), whereas activity of glutathione
reductase (GR) was increased. Increased activity of GR was due to induction of natural defense mechanism of erythrocyte against the toxicity of the pesticide. A lower SOD activity favours lipid peroxidation induced membrane
damage by cypermethrin which in turn reduced activities of membrane-bound enzymes, such as AChE, Na + K + - ATPase and Ca 2+ - ATPase. The decrease in antioxidant enzymes (SOD, CAT, G6PDH) activities have been
interpreted as an indirect inhibition of the enzymes resulting from the binding of oxidative molecules produced during cypermethrin metabolism. In contrast, increased GR activity might result from an activation of the compensatory mechanism leading to induction of free radical scavenging enzymes to counteract the oxidative stress generated by the pesticides. Overall, altered activities of erythrocyte and erythrocyte membrane enzymes indicate
oxidative stress involving free radicals induced by cypermethrin.
concentrations (0, 5, 10, 15 and 20) μg/L of cypermethrin in dechlorinated water. The most outstanding results of this study were found for superoxide dismutase (SOD) and acetylcholinesterase (AChE) activities in erythrocyte and erythrocyte membrane respectively. Cypermethrin resulted in decreased erythrocyte glucose-6-phosphate dehydrogenase (G6PDH), glutathione peroxidase (GPx) and catalase (CAT), whereas activity of glutathione
reductase (GR) was increased. Increased activity of GR was due to induction of natural defense mechanism of erythrocyte against the toxicity of the pesticide. A lower SOD activity favours lipid peroxidation induced membrane
damage by cypermethrin which in turn reduced activities of membrane-bound enzymes, such as AChE, Na + K + - ATPase and Ca 2+ - ATPase. The decrease in antioxidant enzymes (SOD, CAT, G6PDH) activities have been
interpreted as an indirect inhibition of the enzymes resulting from the binding of oxidative molecules produced during cypermethrin metabolism. In contrast, increased GR activity might result from an activation of the compensatory mechanism leading to induction of free radical scavenging enzymes to counteract the oxidative stress generated by the pesticides. Overall, altered activities of erythrocyte and erythrocyte membrane enzymes indicate
oxidative stress involving free radicals induced by cypermethrin.
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