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Acute exposure to high altitudes can cause neurological dysfunction due to decreased oxygen availability to the brain. In this study, the protective effects of Huperzine A on cognitive deficits along with oxidative and apoptotic damage, due to acute hypobaric hypoxia, were investigated in male Sprague-Dawley rats. Rats were exposed to simulated hypobaric hypoxia at 6,000 m in a specially fabricated animal decompression chamber while receiving daily Huperzine A orally at the dose of 0.05 or 0.1 mg/kg body weight. After exposure to hypobaric hypoxia for 5 days, rats were trained in a Morris Water Maze for 5 consecutive days. Subsequent trials revealed Huperzine A supplementation at a dose of 0.1 mg/kg body weight restored spatial memory significantly, as evident from decreased escape latency and path length to reach the hidden platform, and the increase in number of times of crossing the former platform location and time spent in the former platform quadrant. In addition, after exposure to hypobaric hypoxia, animals were sacrificed and biomarkers of oxidative damage, such as reactive oxygen species, lipid peroxidation, lactate dehydrogenase activity, reduced glutathione, oxidized glutathione and superoxide dismutase were studied in the hippocampus. Expression levels of pro-apoptotic proteins (Bax, caspase-3) and anti-apoptotic protein (Bcl-2) of hippocampal tissues were evaluated by Western blotting. There was a significant increase in oxidative stress along with increased expression of apoptotic proteins in hypoxia exposed rats, which was significantly improved by oral Huperzine A at 0.1 mg/kg body weight. These results suggest that supplementation with Huperzine A improves cognitive deficits, reduces oxidative stress and inhibits the apoptotic cascade induced by acute hypobaric hypoxia.

Objective(s): The aim of this study is to explore the potential neuroprotective effects of Ginkgolide B (GB), a main terpene lactone and active component in Ginkgo biloba, in hypoxia-induced neuronal damage, and to further investigate its possible mechanisms.Materials and Methods: 54 Sprague-Dawley rats were randomly divided into three groups: the untreated control group (n=18); the hypoxia group (n=18; exposed to 6000 m simulated plateau altitude for six days); and the GB group (n=18; intragastric administration of 12 mg/kg GB three days prior to rapid adaption to 6000 m and on the first two days of hypoxia). After hypoxia exposure for six days, we dissected out the brain hippocampi and performed hematoxylin and eosin staining, Nissl staining, and TUNEL staining. Homogenates of the hippocampi were used to test the oxidative stress indices including malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and catalase. Bax and caspase-3 expression in the hippocampal tissue was measured using qRT-PCR.Results: Treatment with GB before exposure to hypoxia could protect neural cells and increase the number of Nissl bodies. TUNEL and qRT-PCR results demonstrated that GB treatment could decrease apoptotic cells in different areas of the hippocampus. Antioxidant defense systems such as SOD, GSH, and catalase were decreased (P