Sodium Fluoride Toxicity in the Fresh Water Cat Fish Clariaas batrachus (Linn.): Effects on the Erythrocyte Morphology and Antioxidant Enzymes

摘要

Fluoride is a naturally occurring compound present in the earth's crust which enters the ground and surface waters through natural and anthropogenic sources. Aquatic life is continuously exposed to high concentrations of fluoride in surface waters andharmful effects ensue when fluoride enters the food chain. Fluoride tends to be accumulated in the exoskeletons of invertebrates and in the bone tissues of fishes. The fluoride ions act as enzymatic poisons, inhibiting enzyme activity and, ultimately, interrupting metabolic processes, such as, glycolysis and synthesis of proteins. The present study consists of toxic effects of sub lethal concentration of NaF on the morphology of blood cells and antioxidant enzymes of the edible catfish Clarias batrachus under laboratory condition. Results indicate concentration and duration of exposure dependent induction of oxidative stress and subsequent alternations in the activities of antioxidant enzymes, superoxide dismutase and catalase. Changes in the morphology of blood cells like appearance of agglutination of blood cells, anisocytosis, schizocytosis, echinocytosis, hypochromasia, crenation, pyknocytes and cell fragmentation suggest activation of apoptotic machinery in the blood cells and these results appears to be related to a persistent condition of oxidative stress.