(A) Young male mice were subjected to permanent MCAO followed by treatment with IAIP or vehicle. (B) Infarct quantification after permanent MCA occlusion showed neuroprotection in the cortex (*P = 0.0185), striatum (**P = 0.0054), and total hemisphere (*P = 0.0111) at 48 hours after stroke with IAIP compared with the vehicle group by 2-sample t tests adjusted for multiple testing. (C) NDS 24 hours after stroke with IAIP and vehicle treatment (P = 0.0706, Wilcoxon’s rank sum test). (D) IAIP-treated mice had a significantly longer latency to fall in the grip test 48 hours after stroke (*P = 0.0378, t test). (E) Young male mice subjected to embolic stroke followed by t-PA administration were randomly assigned to IAIP or vehicle treatment as shown in the timeline. (F) Mice that received IAIP in combination with t-PA had reduced infarct compared with mice treated with t-PA and vehicle after thromboembolic stroke (mean ± SEM; *P = 0.0290, 2-sample t test). (G) Mice treated with t-PA plus IAIP after thromboembolic stroke demonstrated a significantly improved NDS 24 hours after stroke (*P = 0.046, Wilcoxon’s rank sum test). (H) IAIP-treated mice had a longer latency to fall in the hang-wire test 48 hours after stroke (**P = 0.0015, t test). (I) Mice that received IAIP had significantly reduced hemoglobin levels in the ipsilateral hemisphere (*P = 0.0487, t test). (J) Representative immunohistochemistry images analyzed 48 hours after thromboembolic stroke showed that IAIP reduced BBB leakage, as seen by fibrinogen immunoreactivity (red), counterstained with lectin (blue). Scale bars: 75 μm. (K) Quantification of fibrinogen immunoreactivity in the ipsilateral hemisphere of mice treated with t-PA plus IAIP compared with vehicle-treated mice (mean ± SEM; *P = 0.0196, t test).