Abstract
Objective: To investigate the effect of aqueous extract of Astragalus membranaceus on cognitive ability of rats living at high altitude. Methods: Rats were exposed to a simulated highaltitude hypobaric hypoxia chamber. The behavior of rats was tested by eight-arm maze. The contents of malondialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS) and activity of total superoxide dismutase (T-SOD) in hippocampus were measured. The expressions of mammalian target of rapamycin (mTOR) and cleaved capase-3 in hippocampus were determined by reverse transcription-polymerase chain reaction and Western blot. Results: The behavioral cognitive ability of the hypoxic control group was significantly lower than that of the normoxic control group. Under hypoxic environment, after the administration of aqueous extract of Astragalus membranaceus, the behavioral cognitive ability of rats was significantly improved. In hippocampal tissue, the content of MDA and ROS were significantly decreased, while the content of GSH and activity of T-SOD in hippocampus were significantly increased. The mRNA expression of mTOR and P70S6K and the protein expression of p-mTOR were significantly increased; the mRNA expression of 4E-binding protein 1 (4E-BP1) and the protein expression of phosphorylated-4E-BP1 (p-4EBP1) and cleaved capase-3 were significantly decreased. Conclusion: When the rats are exposed to high altitude hypoxia, the behavioral cognitive ability could be significantly reduced. Aqueous extract of Astragalus membranaceus can significantly improve cognitive function in rats under hypoxia. The potential mechanism is related to improving oxidative stress, reducing the accumulation of free radicals and metabolites, and activating mTOR signaling pathway.