In vivo fibrinolysis in Plg/pCPB mice. A pulmonary clot lysis model was used in which a 125I-fibrin clot was injected into the jugular vein of mice. The injected clot embolized primarily to the lungs and heart, and these organs were recovered after 4 hours and counted for radioactivity. The radioactivity in these organs is expressed as a percentage of the injected radioactivity to indicate the extent of fibrinolysis. (a) Fibrinolysis in Plg transgenic mice. Fibrinolysis in the Plg+/– mice (n = 6) is significantly different from the Plg+/+ (P = 0.003) and the Plg–/– (P = 0.0007) mice by t test. (b) Fibrinolysis in Plg+/–/ pCPB transgenic mice (n = 5–6 mice). *P < 0.0001 compared with pCPB+/+ by ANOVA. A significant difference was also found between pCPB+/– and pCPB–/– mice in the Plg+/– background (P = 0.0009 by t test).