Figure 2: Expression ratio (xenon to control) of hypoxia inducible factor 1 alpha (HIF-1α). Compared to air-breathing animals, animals exposed to 75% xenon for 120 min demonstrated a significant 2.3-fold increase in HIF-1α transcript (** 𝑃 < 0 . 0 0 5 ) with no increase in reference gene (glyceraldehyde-3-phosphate dehydrogenase (G3PDH)) expression (reverse transcription polymerase chain reaction analysis). Error bars represent standard error of the mean.