Dihuang Yinzi Ameliorates Cognitive Impairments and Inhibits Ferroptosis in APP/PS1 Mice.

Abstract

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and neuronal loss. Ferroptosis, a form of regulated cell death driven by iron overload and lipid peroxidation, has been implicated in AD pathology. DiHuangYinZi (DHYZ), a traditional Chinese herbal remedy, has been suggested to ameliorate cognitive impairments and reduce ferroptosis in AD models. This study aimed to investigate the effects of DHYZ on learning, memory, ferroptosis markers, and neuronal integrity in APP/PS1 transgenic mice. Six-month-old APP/PS1 transgenic mice were treated with DHYZ or donepezil for four weeks. Learning and memory functions were evaluated using the Morris Water Maze (MWM) and open field test. Neuronal integrity was assessed through Hematoxylin and Eosin (H&E) and Nissl staining. Ferroptosis markers, including superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), and the GSH/GSSG ratio, were measured in hippocampal tissues. Ferroptosis-related protein expressions, such as ferritin, DMT1, FPN1, Nrf2, and GPX4, were analyzed using Western blot. DHYZ treatment significantly improved learning and memory deficits in APP/PS1 mice, as evidenced by reduced escape latency and increased platform crossings in the MWM. DHYZ also reversed anxiety-like behavior in the open field test. Histological analysis showed that DHYZ treatment restored neuronal integrity, as indicated by better cellular arrangement and staining compared to untreated APP/PS1 mice. DHYZ inhibited ferroptosis by reducing iron overload, increasing SOD and GSH levels, and normalizing the GSH/GSSG ratio. Moreover, DHYZ modulated the expression of ferroptosis-related proteins, restoring FPN1 levels while reducing ferritin and DMT1 expressions. Nrf2 and GPX4 levels, which were reduced in APP/PS1 mice, were significantly increased after DHYZ treatment. DHYZ effectively improved cognitive deficits, inhibited ferroptosis, and restored neuronal integrity in APP/PS1 mice. These findings suggest that DHYZ may have therapeutic potential for AD by targeting ferroptosis and regulating iron metabolism.