To further investigate whether IFNβ-mediated modulation of MG phenotypes contributes to the protective effect of IFNβ on lessening delayed tPA-aggravated BBB disruption in ischemic stroke, we assessed the severity of BBB disruption in Ifnar1fl/fl-Cx3cr1CreERT2/+ and Cx3cr1CreERT2/+ MCAO mice treated with delayed tPA in the presence or absence of IFNβ. The gene discussed is IFNB1; the disease is ischemic stroke.