IFNβ alleviates delayed tPA–aggravated BBB disruption and HT in ischemic stroke. (A) Mice were subjected to 3-hour MCAO followed by IV administration of vehicle, tPA, or tPA plus IFNβ. Mice were then injected with Evans blue 1 hour before euthanization, and the ischemic brains were harvested at 6.5 hours postinjury followed by imaging and sectioning. The Evans blue leakage in the contralateral (Con) and ipsilateral (Ipsi) hemispheres was quantified (n = 10 per group). (B) Three-hour MCAO mice were administered with vehicle, tPA, or tPA plus IFNβ at 3 hours postinjury. The ischemic brains were harvested at 20 hours postinjury followed by sectioning and imaging. The representative brain section images are shown. (C) The representative hematoxylin and eosin staining images of 3 independent experiments are shown. Scale bar, 50 µm. (D) The levels of hemoglobin in the ipsilateral hemisphere of vehicle-, tPA-, and tPA plus IFNβ-treated MCAO mice were measured (n = 11 per group). *P < .05, ***P < .001 by 1-way ANOVA. A, anterior surface; P, posterior surface.