Effects of repetitive hypobaric hypoxia exposure on the transcriptomic profiles of cerebral cortex and hippocampus in rats

Hypobaric hypoxia (HH) exposure poses a significant risk to personnel safety within the realm of military aviation, especially due to its potential damage to brain functionality in physiological and psychological ways. The present study employed a rodent model to investigate the impact of repetitive HH exposure on brain functionality from a transcriptomic perspective. The treatments were conducted by subjecting rats to HH exposure in a hypobaric chamber device for six times, followed by the collection of brain cortex and hippocampus at 24 and 48 h subsequent to the final exposure. Transcriptomic analysis identified a total of 177 differentially expressed genes (DEGs) in the hippocampus, contrasting with 7 DEGs in the cortex post-treatment. Subsequent gene ontology (GO) analysis showed that the majority of hippocampal DEGs are associated with the GO terms related to the functionality of sensory nervous system. Meanwhile, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis pointed out the enriched mechanisms related to Wnt signaling, melanogenesis, etc. Acute inflammatory responses and cellular apoptosis were almost negligible in rats after repetitive HH exposure. It is significant to note that repetitive HH exposure induces the cerebral expression of elevated concentrations of heat shock protein 90 (HSP90), which may confer neuroprotective benefits to the brain. The findings herein provide valuable information for the health of military aviation personnel engaged in hypobaric hypoxic operations or training. Overall design: Min-Yu, Tu