Rebleeding time, an indicator of thrombus stability, was measured as the time between the cessation of bleeding and the start of the second bleeding (Figure 2B). Rebleeding times were significantly higher in A/J (2.6-fold, P < 0.001) mice than the B6 mice. In contrast, the rebleeding time was nearly 8.5-fold less in the Lepob mice than the B6 mice. To determine how alterations in the fibrinolytic system may affect rebleeding time, Plg-/- and PAI-1-/- mice were also tested (Figure 2B). Rebleeding time was not different in Plg-/- mice compared to WT littermates, but PAI-1-/- mice had a significantly (P < 0.05) reduced rebleeding time, which was 1.8-fold lower than for the B6 mice. Although a Plg deficiency did not result in a prolonged rebleeding time as anticipated, a PAI-1 deficiency resulted in a shortened time. The markedly increased rebleeding time in the A/J may suggest differences in the regulation of the Plg network.