The Effect of Kaempferol on Autophagy and Nrf-2 Signaling in a Rat Model of Aβ1-42-induced Alzheimer’s Disease

Numerous pieces of evidence support that oxidative stress is a key factor in the pathogenesis of neurodegenerative diseases, like Alzheimer’s Disease (AD). Suppression of oxidative stress is an attractive strategy and flavonoids as potent natural antioxidants are extremely noticeable. 

In this study, the effects of Kaempferol (KMP) were evaluated on passive avoidance memory, hippocampal Nrf-2, and beclin-1 expression in a rat model of Aβ1-42 –induced AD.

Forty male Wistar rats weighing 200-250 g were divided into five groups (n=8); sham-operated, AD model, and KMP treatment (5, 7.5, 10 mg/kg, i.p. for three weeks). Animals received an intracerebroventricular injection of amyloid-beta (1-42) to establish an AD model. Passive avoidance memory of rats was evaluated using a shuttle box on day 21; Step-Through Latency (STL) and time spent in The Dark Compartment (TDC) were recorded. Then, hippocampus homogenates were used for biochemical and molecular analysis by real-time PCR, western blot, and ELISA.

It was found that KMP improved memory evidenced by increased STL (P≤0.05) and decreased TDC (p≤0.01). KMP also increased the levels of Total Antioxidant Capacity (TAC) in the hippocampus of rats (P≤0.05). In addition, KMP enhanced the expression of Nrf-2 mRNA (P≤0.001) and beclin-1 protein in the hippocampus tissues (P≤0.001).

Overall, it is suggested that the memory-improving effect of KMP is mediated, at least in part, by enhancing Nrf-2 and TAC. KMP is also able to induce autophagy through the expression of beclin-1.