Protective effect of honey on learning and memory impairment, depression and neurodegenerationinduced by chronic unpredictable mild stress

Introduction: Chronic stress, which has been prevalent in human life, induce structural changes in the hippocampus. Depression and impairment of memory are serious comorbidities of chronic stress. In this study, we evaluated the impact of an Iranian honey pretreatment on memory deficit, depression and the hippocampal neuronal loss in the chronic unpredictable mild stress (CUMS) model. Methods: Adult male Wistar rats were divided into the control groups that received water or honey (0.2 or 2g/kg) and CUMS groups that subjected different, randomly and unpredictable mild stressors for 4 weeks. Ten days before starting the CUMS procedures, the animals received honey (0.2 or 2g/kg, daily, orally), which was continued until sacrificing. Morris water maze and sucrose performance tests were used to evaluate the spatial learning and memory and depressive-like behavior in the animals respectively. Hippocampus and whole brain samples were collected for further biochemical and histological analysis. Results: Honey reversed the depression-like behavior and ameliorated the spatial memory deficit induced by CUMS. Also, honey decreased cell death in the hippocampus and reduced the malondialdehyde level in treated animals. Conclusion: These results revealed that honey diminished learning and memory deficits and depression in chronic stress conditions.