Background: Lindane is a persistent, bioaccumulative, and toxic organochlorineinsecticide. Human exposure to lindane (gamma hexachlorohexane) occurs via food and water. It is largelyknown to cause toxicity in various organs, such as the liver, brain, and testes. Appreciable amountsof lindane also accumulate in the heart. However, the effect of chronic lindane exposure on the heartis not well investigated. Material/Methods: The present study was designed to explore the effect of oraladministration of lindane (1.5 and 7 mg/kg/day for 21 days) on lipid peroxidation, endogenous antioxidants(GSH, SOD and catalase), and histopathological changes (light and electron microscopic studies) of rathearts. Results: Lipid peroxidation of the heart, as measured by thiobarbituric acid reactive substances,(TBARS) was increased, with a decrease in GSH level. An increase in SOD and catalase activities was observedin the 7-mg/kg/day dose of lindane. Interstitial edema in the myocardium was observed in both doses.Ultrastructural changes consisted of loss of integrity of the myofibrils, Z-band disruption, and mitochondrialdamage. Conclusions: This is the first study to report lindane-induced oxidative stress in the heart.Our observations have significant clinical relevance, as oxidative stress plays a key role in the pathogenesisand progression of major cardiovascular disorders.

Keywords: Lindane - toxicity, Thiobarbituric Acid Reactive Substances - metabolism, Superoxide Dismutase - metabolism, Rats, Wistar, Oxidative Stress - drug effects, Myocardium - ultrastructure, Microscopy, Electron, Lipid Peroxidation - drug effects, Antioxidants - metabolism, Insecticides - toxicity, Heart - drug effects, Glutathione - metabolism, Catalase - metabolism, Administration, Oral