Effect of FXI ASO, warfarin, or Levonox therapy on thrombosis and bleeding in mice. (A) Male BALB/c mice were treated with either FXI ASO at doses ranging from 1.25 to 40 mg/kg administered subcutaneously twice weekly for 3 weeks, or warfarin, which was injected intraperitoneally once daily for a period of 6 days with the final dose injected approximately 4 hours before endpoint measurements (n = 10). Thrombosis was induced by 3-minute exposure of the IVC to a 10% FeCl₃ solution and assessed by RT-PCR measurement of PF4 mRNA levels at the site of injury. (B) Effect of FXI antisense and warfarin treatment at indicated doses on tail bleeding in male BALB/c mice (n = 10). (Inset) Male C57BL/6 mice were treated with FXI ASO, control ASOs (25 mg/kg, subcutaneously injected twice/week for 3 weeks), or Lovenox (single dose of 25 mg/kg injected subcutaneously 2.5 hours before bleeding measurements), and the effects on tail bleeding were evaluated (n = 8, 8 and 6 mice per treatment group, respectively).