Effect of Adamts13 gene deletion on brain infarct in mice after 30-minute MCAO. (A) These are coronal sections through the brain in both groups stained with 2,3,5 triphenyltetrazolium chloride. Red areas represent vital brain tissue, and white areas represent cerebral infarction. Adamts13^−/− (−/−) mice had significantly larger volume of brain infarct compared with wild-type (+/+) mice after 23.5-hour reperfusion after 30-minute MCAO (−/−, n = 16, vs +/+, n = 16, **P < .01, Student t test). Values are mean ± SEM (mm³). The average infarct volume was 31.0 ± 6.5 mm³ for ADAMTS13 ^−/− mice and 11.4 ± 1.9 mm³ for +/+ mice. The survival rates of the −/− and +/+ mice did not differ (17 of 20 vs 16 of 20, respectively). No ischemic change was observed in the brain of −/− and +/+ mice after sham operation. (B) Neurologic score was measured 24 hours after MCAO. Neurologic scores were measured from the point according to the neurologic findings as follows: 0 indicates normal motor function; 1, flexion of torso and of contralateral forelimb on lifting of the animal by the tail; 2, circling to the ipsilateral side but normal posture at rest; 3, circling to the ipsilateral side; 4, rolling to the ipsilateral side; and 5, leaning to the ipsilateral side at rest (no spontaneous motor activity). *P < .05. (C) Representative PTAH-stained sections of infarct area for wild-type (+/+) and Adamts13^−/− (−/−) mice. There were more thrombi and inflammatory cells in the lesions of Adamts13^−/− mice compared with +/+ mice (black arrows represent thrombus; white arrow, inflammatory cells infiltration). The area comparable with PTAH staining for −/− mice was immunostained using anti-VWF antibody. VWF is detected in thrombi as brown staining (−/− ipsilateral anti-VWF). Images were generated using an Olympus BH-2 microscope with an Olympus DP20-5 digital camera (original magnification ×200). Bar represents 40 μm.