Kaempferol promotes memory retention and density of hippocampal CA1 neurons in intra-cerebroventricular STZ-induced experimental AD model in Wistar rats

Abstract

Background. Alzheimer’s disease (AD) is a progressive degenerative disease which causes memory disorders, decreases cognitive functions and abilities, and results in behavioural changes. Some studies have indicated that the flavonoids are able to cross the blood–brain barrier and have a positive effect on the reduction of neuronal damage disorders in the brain such as Alzheimer’s disease. Materials and Methods. ICV administration of streptozotocin (3 mg/kg) was done on the first and the third day of the surgery and the animals’ memory was evaluated through passive avoidance tasks. Animals were divided into five groups: Salin-Salin, STZ-Salin, and STZ- different kaempferol doses (5, 7/5, 10 mg/kg). All animals received different doses of kaempferol or saline for 3 weeks starting one day before the surgery. Later, they were put into a learning test. After the memory test, the animals were killed and their brains were fixed with Paraformaldehyde 4%, and tissue processing was done. Finally, density of intact neurons in the CA1 area of the hippocampus in the brains of all groups was investigated. Results. The ICV injections of STZ significantly reduced memory retention and intact pyramidal cells compared to the control group. The kaempferol improved the effects of STZ. Conclusion. Our findings show that kaempferol can optimize cognitive deficits caused by injections of STZ and also has some useful impacts on hippocampal CA1 pyramidal neurons.