Orally administered melatonin protects against adrenaline-induced oxidative stress in rat liver and heart: Involvement of antioxidant mechanism(s)

The present studies intended to investigate the protective effects of melatonin (5mg/kg bw, fed orally) against adrenaline (0.25mg/kg of body weight, s.c. for a period of 15 days) induced oxidative stress in rat liver and heart through certain antioxidative indices like Cu-Zn superoxide dismutase (Cu-Zn SOD), Mn superoxide dismutase (Mn SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), reduced glutathione (GSH) and lipid peroxidation (LPO), other biochemical parameters such as mitochondrial Kreb’s cycle enzymes as well as respiratory chain enzymes were also measured. Antioxidative enzymes and other parameters showed a significant reduction while LPO, Mn SOD and reduced glutathione levels increased significantly in adrenaline-treated rats as compared to control groups. These biochemical changes were supported through our studies on tissue morphology. However, all these parameters were protected from being altered when rats were pre-treated with melatonin. The present studies perhaps for the first time comprehensively indicated that melatonin has the potential to provide protection against adrenaline-induced tissue injury and further strengthen the notion that this indole may be relevant therapeutically in future days in humans exposed to various stressful situations.