In vivo effects of stroma-free hemoglobin and polyhemoglobin on coagulation factors in rats.

We studied the effects of rat stroma-free hemoglobin (rSFH), human stroma-free hemoglobin (hSFH), rat polyhemoglobin (rPoly), and human polyhemoglobin (hPoly) on coagulation factors in rats. Albumin and saline infused rats were controls. The infusion volume was 10% of the rat's blood volume. The concentrations of hemoglobin in this study were 7 g/dl. Measurements for prothrombin time (PT) and activated partial thromboplastin time (PTT) were at 5 minutes, 2, 6, 24 and 72 hours after infusion. Factor X, fibrinogen, plasminogen, antithrombin III, and antiplasmin were followed at 24 and 72 hours after infusion. Compared with saline infused rats PT and PTT did not change significantly in those rats infused with Hb preparations. There was a transient increase of PTT from 2 to 24 hours after infusion in albumin infused rats. Factor X, fibrinogen, antithrombin III and antiplasmin showed no significant differences between Hb infused groups and saline infused group. Twenty-four hours and 72 hours after infusion plasminogen decreased in all groups except the albumin infused rats at 24 hours after infusion when compared with normal rat plasma pool. However, there were no significant differences in plasminogen levels between the hemoglobin infused groups and the control saline group. Stroma-free and polyHb solutions (rSFH, hSFH, rPoly and hPoly) did not cause significant changes in prothrombin time and activated partial thromboplastin time in rats. The rats infused with hemoglobin solutions (rSFH, hSFH, rPoly, and hPoly) did not show significant differences in Factor X, fibrinogen, antithrombin III and antiplasmin levels compared with the control group.