H₂ O₂ contributes to mTORC1-dependent platelet activation during aging. FACS analysis of platelets (A) and MKs (B) from 4- or 16-month-old mice for intracellular H₂O₂ levels (n = 10). MFI values represent means ± SEM; **P < .01. (C) Western blot analysis of mouse platelets from 4- and 16-month-old WT or Raptor KO mice stimulated with 50 μM H₂O₂ for 30 minutes for mTORC1 activity. (D) Complete blood count analysis of 4- and 16-month-old mice administered NAC for 2 months (n = 10). MPV and platelets are shown. Values represent means ± SEM; *P < .05; **P < .01. (E) VWF IHC staining of femur bone sections from mice described in panel D. (F) Quantification of MK size is illustrated. Values represent means ± SEM; *P < .05. (G) PF4 ELISA analysis of plasma from mice described in panel D. Values represent means ± SEM; **P < .01. FACS analysis (H) of platelets incubated with 0.2 U/mL thrombin for 15 minutes at room temperature from mice described in panel D for integrin αIIbβ3 activation (n = 10) and quantification (I) illustrated. Values represent means ± SEM; *P < .05; **P < .01. Weights (J) and lengths (K) of thrombi that developed in the IVC 48 hours after ligation were measured in 4- and 16-month-old mice administered NAC for 2 months (n = 6). Values represent means ± SE; **P < .01.