Hemostatic Effects of Raloxifene in Ovariectomized Rats

This study aimed to explore the effects of raloxifene (Rx) and estradiol (E-2) on prothrombin time (PT), partial thromboplastin time (APTT), coagulation factors (VII, X, XI), and fibrinogen concentrations in rats. Female rats were ovariectomized 11 days prior to starting the treatment. Afterward, they received Rx or E2 (1, 10, 100, and 1000 mu g/kg) or propylene glycol (0.3 mL; vehicle, V) subcutaneously for 3 consecutive days. Plasma was collected to measure the hemostatic parameters. Rx significantly increased PT (8%, at 1000 mu g/kg; p < 0.05) and APTT at all doses evaluated (32, 70, 67, 30%; p < 0.05, respectively). Rx (1, 10, 100, and 1000 mu g/kg) decreased the activity of factor VII by -20, -40, -37, and -17% (p < 0.05), respectively, and E-2 increased it by 9, 34, 52, and 29%. Rx reduced factor X activity at 10 and 100 mu g/kg doses (-30, and -30% p < 0.05), and E-2 showed an increment of 24% with 1000 mu g/kg dose only. Additionally, Rx (1, 10, 100 mu g/kg) diminished FXI activity (-71, -62, -66; p < 0.05), E-2 (1 and 10 mu g/kg) in -60 and -38, respectively (p < 0.05), and Rx (1000 mu g/kg) produced an increment of 29% (p < 0.05) in fibrinogen concentration, but not E-2. Our findings suggest that raloxifene has a protective effect on hemostasis in rats.