Neuroprotective and antioxidant effect of bee honey in the rat hippocampus under chronic unpredictable mild stress

Background and Aim : Chronic stress, an external or internal stimulation, severely increases HPA activity, free radicals component, lipid peroxidation, and decrease in total antioxidant capacity in the hippocampus, which induces inflammation, neuronal loss, and neurodegeneration. Bee honey is a natural and accessible product that has exhibited antioxidant capacity. Honey has different components, such as phenolic acids, flavonoids, coumaric acid. These ingredients prevent auto-oxidation reactions and free radicals production. In the current study, we investigated the pretreatment effect of honey on total antioxidant capacity (TAC), malondialdehyde (MDA) as lipid peroxidation index, and neuronal loss in the hippocampus of the animals that were affected by the chronic mild unpredictable stress (CUMS).Methods : 1o days before CUMS induction, honey (dose 0.2 and 2 g/kg, daily, orally) was delivered to the rats and continued until euthanasia. Animals were exposed to CUMS for 28 days. After this duration, the hippocampus was collected and stored at -80°C. TAC and MDA kit were used respectively to analyze the differences of total antioxidant capacity and lipid peroxidation in control and treated groups. Also, three brain samples were fixed in each group for further histological analysis. Nissl staining was performed to evaluate the cell density in CA1 and CA3 of the hippocampus.Results : A trend of increased and decrease in TAC and MDA, respectively, has been shown in the hippocampus of the stressed animals, which were under pretreatment with honey, but data was not significant. Neuronal loss in both CA1 and CA3 of the stress group was significantly higher than the control animals (P<0.001). Quantitative analysis of Nissl staining revealed an increase in cell density in treated groups compare to the CUMS group (P<0.01 and P<0.001 in CA1 and CA3 in a dose of 2 g/kg respectively and P<0.05 in CA1 in a dose of 0.2 g/kg).Conclusion : Pretreatment with honey in the chronic mild stress conditions may improve antioxidant capacity, prevents lipid peroxidation, and also has a neuroprotective effect on hippocampal neurons.

کلیدواژه ها:

Bee honey ، hippocampus ، neuroprotection ، total antioxidant capacity ، malondialdehyde