Abstract
Cancer is a critical health problem, and chemotherapy administration is mandatory for its eradication. However, chemotherapy like doxorubicin (Dox) has serious side-effects including cognitive impairment or chemo brain. Melatonin is a neuroprotective agent that has antioxidant, and anti-inflammatory effects. We aimed to explore melatonin's effect on Dox-induced chemo brain to discover new mechanisms associated with Dox-induced neurotoxicity and try to prevent its occurrence. Thirty-two male albino rats had been equally divided into four groups; control, melatonin-administrated, Dox-induced chemo brain, and melatonin + Dox treated. On the 9th day, brain had been excised after scarification and had been assessed for reactive oxygen species measurement, histopathological analysis, immunohistochemical, gene and protein expressions for the nuclear factor erythroid 2-related factor 2 (Nrf2), p53 and Silent information regulator 2 homolog 1 (SIRT1). Our results show that melatonin coadministration diminished Dox induced hippocampal and prefrontal cortex (PFC) cellular degeneration. It alleviated Nitric Oxide (NO) level and reversed the decline of antioxidant enzyme activities. It also upregulated Nrf2, SIRT1 and downregulated p53 gene expression in rats receiving Dox. Moreover, melatonin elevated the protein expression level of Nrf2, SIRT1 and reduced p53 corresponding to immunohistochemical results. The data suggested that melatonin can mitigate Dox-induced neurotoxicity by aggravating the endogenous antioxidants and inducing neurogenesis through activation of Nrf2/p53-SIRT1signaling pathway in adult rats' PFC. These effects were associated with Nrf2, SIRT1 activation and p53 inhibition. This could be guidance to add melatonin as an adjuvant supplement to Dox regimens to limit its adverse effect on the brain function.