Investigation of zinc and copper levels in methimazole-induced hypothyroidism: relation with the oxidant-antioxidant status

Thyroid hormones are associated with the oxidative and antioxidative status of the organism. Depression of metabolism by hypothyroidism has been reported to decrease oxidant production and thus protect tissues against oxidant damage. The purpose of the present study was to investigate Zn and Cu levels in MMI-induced hypothyroidism and to show whether there is a connection between these trace elements and the oxidant-antioxidant status in experimental hypothyroidism. 3-Nitrotyrosine was measured as a marker of nitro-oxidative stress. In order to examine the antioxidant status of MMI-induced hypothyroidism in rats, GSH and SOD levels were determined as well. Significantly decreased 3-nitrotyrosine, Cu and Zn levels were observed in our experimental model when compared with the controls. On the other hand, GSH and SOD levels remained constant. It may be suggested that Cu and Zn serve as antioxidant molecules and exert their effects in an indirect manner to reduce oxidative stress in experimental hypothyroidism.

Evaluation of lipid peroxidation and total antioxidant status in plasma of rats following thermal injury

Thermal injury initiates systemic inflammatory reactions producing burn toxins, an inflammatory response, oxygen radicals and finally peroxidation. The relationship between the amount of products of oxidative metabolism and natural scavengers of free radicals determines the outcome of local and distant tissue damage, and further organ failure in burn injury. To determine the relationship between the level of total natural scavengers of the body, the place of superoxide dismutase in this capacity, and its relation with lipid peroxidation, malondialdehyde, superoxide dismutase levels and total antioxidant status were measured in plasma. Animals were subjected to 30 per cent full thickness body surface area burn, and their blood was collected at 24 h postburn. Plasma malondialdehyde levels were significantly elevated above the level of controls (P < 0.02). Burn injury caused a remarkable decrease in superoxide dismutase (45 per cent decrease, P < 0.0001) and total antioxidant status (14 per cent decrease, P < 0.01) when compared to control.