Summary
In a rat model of lipopolysaccharide (LPS)-induced disseminated intravascular coagulation
(DIC), we used urokinase (UK) in an attempt to clarify the role of fibrinolysis and
to investigate changes in plasma endothelin levels. Two kinds of experiment were performed.
The first one: experimental DIC was induced by sustained infusion of 30 mg/kg LPS
for 4 h via the tail vein, and two doses of UK (2.0 or 10.0 IU/g/4.5 h) were administered
to rats 30 min before infusion of LPS, after which UK infusion was continued for a
further 4 h. The second one: experimental DIC was induced by sustained infusion of
1 mg/kg/10 min LPS for 10 min, and two doses of UK (2.0 or 10.0 IU/g/4 h) were administered
to rats at 30 min after LPS infusion. The parameters described below were determined
at 4 h in the first experiment, at 4 h and 8 h in the second one. The similar results
were observed in both kinds of experiment. There were no significant differences in
plasma thrombin-antithrombin complex, fibrinogen or platelet number among the three
DIC groups, in both kinds of experiment. Plasma levels of D-dimer were significantly
increased in the LPS + higher dose of UK group when compared with the LPS group. The
increased plasma plasminogen activator inhibitor (PAI) activity seen in the LPS group
was significantly suppressed in the groups receiving UK (especially higher dose of
UK). In addition, the increased plasma levels of creatinine and alanine aminotransferase
seen in the LPS group were significantly suppressed in the groups receiving UK (especially
higher dose of UK). Plasma levels of endothelin, known to be a potent vasoconstrictive
agent, were markedly elevated by LPS infusion, and were significantly suppressed in
the groups receiving UK of both kinds of experiment, in a dose-dependent fashion compared
with LPS group. Glomerular fibrin deposition was significantly suppressed in the groups
receiving UK when compared with the LPS group. No manifestations of bleeding were
observed in any of the groups. Enhanced fibrinolysis and depressed endothelin induced
by UK thus appear to play an important role in preventing the development of organ
failure in the LPS-induced DIC model.
Keywords
DIC - urokinase - fibrinolysis - endothelin