The expression of matrix metalloproteinase-9 (MMP-9) and hypoxia inducible factor (HIF)-1α were significantly higher in the penumbra following cerebral ischemia compared to healthy controls, with no significant difference between tMCAO + argon and tMCAO + placebo (Figures 3B, D). The gene discussed is HIF1A; the disease is Cerebral ischemia.