The effect of melatonin administration on cognitive function, histological and biochemical changes in the hippocampus of male offspring of Wistar rats exposed to arsenic before and after conception

Abstract

One of the most important causes of neurotoxicity and pathogenesis of brain injury is exposure of the fetus to oxidative stress. Studies have shown that arsenic plays a major role in oxidative stress, apoptosis, and DNA damage. On the other hand, melatonin, as a pleiotropic neuroendocrine molecule, has a strong antioxidant role and is very important for the normal growth of the nervous system and the circadian rhythm of the fetus during pregnancy. Due to the lack of daily secretion of melatonin in the first weeks after birth, its deficiency is felt in infancy. Therefore, its complementary use in this period can be useful. With this background, in this study, we examined the effects of melatonin during pregnancy on arsenic-induced disorders that may improve the development of the nervous system in newborns. Methods: In this study, 32 female wistar rats were selected and randomly divided to 4 groups as follow: control, melatonin (10 mg / kg BW melatonin, IP), arsenic (50 mg / L sodium meta arsenate "NaAso2" dissolved in drinking water) and arsenic + melatonin on day 21 postpartum, male offspring (n = 8) from different groups were randomly selected. At the end of two months, behavioral tests including anxiety tests (EPM and OF) and depression (FST) and at the end of 3 months, spatial memory tests (MWM) was performed on offspring. After behavioral tests, the rats were anesthetized and blood samples were taken from the heart and then the hippocampus was dissected for histological and biochemical tests including: oxidative stress, DNA damage, inflammation and apoptosis. Results: Our results showed that there was a significant difference in the level of EPM, OF, FST and MWM indices between control and arsenic groups (P <0.05) On the other hand, administration of melatonin with arsenic improved performance in tests of anxiety and depression and spatial memory compared to the arsenic group (P < 0.05) and protein damage, DNA, lipid peroxidation and arsenic-induced apoptosis in the above group significantly improved compared to the arsenic group (P <0.05).