Microbiota-gut-brain axis imbalance: a promising therapeutic target for preserving brain health in high-altitude environment.

High-altitude hypobaric hypoxia poses a significant threat to brain function, yet effective neuroprotective strategies remain limited. Emerging evidence highlights the microbiota-gut-brain axis (MGBA) as a key mediator in high-altitude-induced cognitive impairment, positioning it as a potential therapeutic target. This review synthesizes current knowledge on how high-altitude exposure dynamically reshapes gut microbial ecology, characterized by reduced diversity, phylum-level instability, and functional metabolic shifts. Furthermore, we delineate how such altitude-induced dysbiosis has been associated with neural dysfunction through interconnected pathogenic mechanisms that are proposed to link gut ecology to brain outcomes: intestinal barrier disruption with metabolic dysregulation, LPS/TLR4-mediated neuroinflammation, vagal and enteric nervous system alterations, oxidative stress imbalance, and neuroendocrine dysregulation. Most current evidence is correlational, and further research is needed to establish causality. A critical unresolved question is whether short-term, transient gut dysbiosis at high altitude can instigate long-lasting neurological deficits independent of ongoing microbial perturbation. We further evaluate microbiota-targeted neuroprotective strategies, including probiotics, prebiotics, and fecal microbiota transplantation, highlighting their distinct mechanisms and summarizing the current evidence supporting MGBA-targeted interventions for high-altitude brain health. Preclinical studies suggest these approaches hold promise by restoring barrier integrity, attenuating inflammatory signaling, and rebalancing microbial metabolite profiles, while human intervention evidence remains scarce. Finally, we discuss critical challenges and future directions for translating these mechanistic insights into personalized interventions, emphasizing deeper mechanistic exploration and the synergistic interactions among microbial taxa. These insights may inform more effective therapeutic strategies for the growing populations residing in or traveling to high-altitude regions.