APC-mediated neuroprotection in ischemic stroke is observed in QQ41-PAR1 mice but not in QQ46-PAR1 mice. Data (mean values) for 24 hours after MCAO are shown for infarct volume (A), edema (B), foot-fault test (C), and forelimb-asymmetry test (D) for homozygous QQ41-PAR1 mice, homozygous QQ46-PAR1 mice, and the corresponding Wt controls treated with murine recombinant 3K3A-APC (0.04 mg/kg given IV 4 hours after MCAO) or vehicle. Bars indicate mean ± standard deviation (SD), n = 4-6 mice per group. Data for 24 hours after MCAO are seen for degenerating neurons determined by Fluoro-Jade C stain (E-F) and for fibrin deposition determined by anti-fibrin antibodies (E,G) for each mouse group (panel E, original magnification ×20). Treatment of mice with 3K3A-APC or vehicle is indicated by plus or minus signs under panels A-D, F, and G. Student t test and 1- or 2-way ANOVA followed by a post hoc Tukey test were used to determine statistically significant differences. The curves of functional recovery after stroke were compared using repeated-measures ANOVA. P < .05 was considered statistically significant.