Abstract
Melatonin has been demonstrated to have anti-inflammatory and antioxidant effects. The aim of this study was to investigate the protective effects of melatonin on arsenic trioxide (As2O3)-induced toxicity in liver and oxidative stress in rats. The rats were injected with 3mg/kg As2O3 on alternate days and melatonin was given with an intraperitoneal injection (i.p.) 1 h before As2O3 treatment. On the 8th days, the rats were killed to determine liver histological injury, antioxidant activities and accumulation of arsenic in liver tissues. Our results showed that melatonin attenuated As2O3-induced hepatic pathological damage, liver parameters, liver ROS level, MDA level, and the retention of arsenic in liver tissues. Melatonin also improved the antioxidant enzymes SOD, GPX, and CAT activity induced by As2O3. Furthermore, melatonin improved the expression of Nrf2 and HO-1. In addition, melatonin was found to activate PI3K/AKT pathway. In conclusion, our results indicated that melatonin protected against As2O3-induced liver injury by inducing Nrf2/HO-1 expression via upregulation of PI3K/AKT pathway.