Platelets from young mice exposed to TNF-α in vivo for 20 consecutive days become hyperreactive. (A) Experimental approach. Representative flow cytometry assessment of the activation of the ⍺_IIbβ₃ integrin of washed platelets (plts) from young mice treated with TNF-⍺ or control (ctrl) for 20 days after activation with (B) thrombin (0.1 U/mL) or (C) convulxin (50 ng/mL), (n = 4-6; mean plus or minus SEM). (D) Whole blood microfluidics assay. Platelet adhesion to collagen-coated slides under flow of young mice treated with TNF-⍺ or control for 20 days (n = 4; mean plus or minus SEM). (E) Representative flow cytometry assessment of the activation of the ⍺_IIbβ₃ integrin of washed platelets from TNFΔ^ARE or littermate controls (n = 3; mean plus or minus SEM). (F) Representative flow cytometry assessment of the activation of the ⍺_IIbβ₃ integrin of washed platelets from young mice treated with IL-1β or control for 20 days (n = 3; mean plus or minus SEM). (G) Whole blood microfluidics assay. Platelet adhesion to collagen-coated slides under flow of young mice treated with IL-1β or control for 20 days (n = 4; mean plus or minus SEM). (H) Flow cytometry assessment of the activation of the ⍺_IIbβ₃ integrin of washed platelets from young C57BL/6J and p55/p75 KO mice treated with TNF-⍺ or control for 20 days after activation with thrombin (0.1 U/mL) or convulxin (50 ng/mL; n = 4-6; mean plus or minus SEM). (I) Microfluidics analysis of whole blood flowed over collagen-coated slides of young C57BL/6J and p55/p75 KO mice treated with TNF-⍺ or control for 20 days (n = 4; mean plus or minus SEM). *P < .05; **P < .01; and ***P < .001. Student t test and Mann-Whitney test. IP, intraperitoneal.