T+RB-PTS is markedly more sensitive to tPA-lytic treatment than RB-PTS. (A-B) Intravital microscopy imaging with DyLight488-conjugated anti-GPIbβ/platelet antibody was used to visualize the clot behaviors during and after vehicle-vs-tPA (10 mg/kg) infusion in single-vessel RB photothrombosis model. Shown are the representative images of the RB clot with the vehicle (A; see also supplemental Video 8; n = 3) or tPA infusion (B; supplemental Video 9; n = 4). Neither tPA or vehicle induced obvious recanalization in the RB photothrombosis model. White arrow indicates the site of photoactivation (20 μm in diameter). Orange arrow indicates the direction of arterial blood flow. (C-D) The same intravital imaging method was used to compare the clot responses to vehicle-vs-tPA (10 mg/kg) infusion after T+RB photothrombosis. The vehicle treatment failed to restore the blood flow (C; supplemental Video 10; n = 3), whereas every tPA-treated mouse manifested recanalization of the occluded artery (arrowheads in D; supplemental Video 11; n = 5). Scale bar, 50 μm.