Acute Changes in Rat Tissue Gene Expression Following Exposure to Flight Relevant Hypobaria

Aeromedical evacuation (AE) is an important tool for transit of injured patients, but both the hypobaria and hyperoxia associated with AE may contribute to secondary injury. We aimed to examine the effects of these acute exposures on gene expression while avoiding the inflammatory storm that would result from injury and potentially mask underlying causes of AE-related secondary injury. We exposed healthy, young male rats to different levels of hypobaria (4000 ft or 8000 ft eqiv.) and/or hyperoxia (100% oxygen) for different durations of time (5 or 10 h). We collected heart, lung, brain (hippocampus), and blood tissue samples, processed them for RNA, and performed microarray analysis on the samples. Heart, lung, and blood RNA was analyzed via Rat Clariom S Assay chips, while hippocampus RNA was analyzed via Rat Gene 2.0 ST Array chips. Treatment groups were combined, outlier samples were removed, and secondary analysis was performed comparing treatment groups against control group (0 ft, 21% oxygen, 5 h) for each tissue type (.TXT files).