Cistanche tubulosa (Schrenk) Wight Extract Ameliorates Learning and Spatial Memory Abilities in High-Altitude Hypobaric Hypoxia Rats

Background: High-altitude hypobaric hypoxia (HH) is a major environmental stressor that impairs cognitive function, yet effective and widely available therapeutics remain limited. Although Rhodiola rosea has shown neuroprotective effects, its resource scarcity restricts large-scale application. Cistanche tubulosa (Schrenk) Wight, a traditional Chinese functional food, has been increasingly used in health supplements due to its anti-fatigue, anti-dementia, and memory-enhancing properties, suggesting potential benefits against hypoxia-induced cognitive impairment. Objective: This study aimed to investigate the effects of C. tubulosa ethanol extract (CTE) on hippocampal tissue and gut microbiota upon chronic HH exposure using SPF male Sprague–Dawley (SD) rats. Methods: A total of 60 male SD rats were randomly assigned to six experimental groups (n = 10 per group): normoxic control, untreated HH model, positive control (R. rosea), and low-, medium-, high-dose CTE treatment groups. Behavioral tests (Morris water maze), hippocampal histopathology, serum and hippocampal oxidative stress markers (SOD, GSH-Px, MDA), expression of PI3K/Akt/mTOR-HIF-1α signaling pathway proteins (by immunohistochemistry), and gut microbiota composition (by 16S rRNA sequencing) were evaluated. Results: The results demonstrated that CTE significantly improved cognitive function, enhanced SOD and GSH activities, and reduced MDA levels in both hippocampus and serum. CTE also modulated the expression of PI3K/Akt/mTOR-HIF-1α pathway proteins in the hippocampus. Furthermore, CTE altered gut microbial diversity and abundance, increasing the proportion of beneficial bacteria, which may further influence hippocampal function via the gut–brain axis. Conclusion: These findings provide scientific evidence for the application of C. tubulosa as a potential health supplement for high-altitude adaptation and lay a foundation for subsequent research.