Analysis of TNF-α chimeric mice and the effects of TNF-α administration revealed the importance of inflammatory cytokine signaling in ECs in our thrombosis model. (A-B) Quantification of platelet attachment and thrombus development after laser/ROS-induced injury in 12-week-old male TNF-α and TNF-R1 KO mice and their wild-type (WT) mice treated with vehicle (PBS) or TNF-α (100 ng/kg; n = 30 vessels from 5 animals for each group). Recombinant TNF-α restored impaired thrombus formation in TNF-α–deficient mice but not in TNF-R1–deficient mice. (C-D) Platelet attachment and thrombus development after laser/ROS injury assessed in WT, WT-chimeric, TNF-α KO-chimeric, TNF-α KO, TNF-R1 KO-chimeric, and TNF-R1 KO mice. None of the chimeric mice showed impaired thrombus formation, in contrast to the total TNF-α KO and TNF-R1 KO mice, indicating that cell types other than blood cells contribute to thrombus formation in our model. Asterisks indicate statistical significance (P < .05).