The increase in MMP-9 is further associated with different alterations, including excitotoxicity, neuronal damage (Lee et al., 2004), apoptosis (Lee and Lo, 2004; Copin et al., 2005), oxidative stress (Kelly et al., 2008), interference with oxidative DNA repair mechanisms (Yang et al., 2010) and BBB opening, leading to cerebral edema and hemorrhagic transformation (Zhao et al., 2006) after cerebral ischemia. The gene discussed is MMP9; the disease is brain ischemia.