Preconditioning effect of cobalt chloride supplementation on hypoxia induced oxidative stress in male albino rats

The present study was designed to understand the preconditioning effect of cobalt chloride (CoCl2), a known hypoxia mimetic, on promoting acclimation to hypobaric hypoxia in male Sprague Dawley rats. Rats were exposed to hypoxia (7619 m) for 1,2,3 and 5 days with and without prior supplementation of cobalt chloride (12.5 mg cobalt/kg bw for 7 days). After hypoxic exposure, rats were sacrificed and various oxidative stress parameters were studied in the blood/plasma. Further protein expression studies were carried out in the heart. The results showed significant increase in lipid peroxidation and protein oxidation and decrease in reduced glutathione (GSH) in the plasma of animals exposed to hypoxia without cobalt supplementation as compared to control group. Prior administration of cobalt appreciably attenuated oxidation of lipids and proteins. There was increase in antioxidant enzyme superoxide dismutase (SOD) on exposure to hypoxia, whereas SOD levels were maintained in cobalt supplemented groups. Expressions of hypoxia inducible factor (HIF-1), hemoxygenase (HO-1) and metallothionein (MT) were higher in the cobalt supplemented group as compared to control group. Therefore, cobalt preconditioning appears to decrease oxidative stress by alleviating lipid peroxidation and maintaining higher HO-1 and MT levels leading to faster acclimation to hypobaric hypoxia.