12/15-LO–induced coagulation contributes to thrombus formation and hemostasis. (A and B) TAT complex formation (n = 6; A) and thrombus formation (n = 4; B) after ferric chloride (FeCl)–induced thrombosis of the IVC in Alox15^−/− mice (C57BL/6 background) and WT littermates. (C) Bleeding assays (15-mm tail cut) with WT (C57BL/6) mice, Alox15^−/− mice, and WT mice treated with baicalein (n = 6 each). Bar graphs show relative weight loss, OD_575nm of the lost blood after lysis, and primary bleeding time (time until first stop of bleeding). (D and E) FeCl-induced IVC thrombus formation in mice carrying an eosinophil-specific deletion of Alox15 (Alox15^fl/fl; n = 10) and their WT littermates (Alox15^+/+; n = 9; D) and mice that received the 12/15-LO inhibitor baicalein (n = 4) and a vehicle (n = 4; E). Data are representative of at least three independent experiments. Error bars represent SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001; Student’s t test. (F) Proposed mechanism of the eosinophil-mediated and 12/15-LO–induced thrombin generation in response to platelet aggregation.