Dexamethasone-prepared Escherichia coli-induced disseminated intravascular coagulation. Animal model.

We have developed a new model of disseminated intravascular coagulation in rats based on the induction of immunosuppression by prolonged high-dose dexamethasone treatment. Most models of disseminated intravascular coagulation are based on the generalized Shwartzman reaction, which is observed characteristically in experimental animals after two separate inoculations of bacterial endotoxins. These produce massive deposition of thrombi in the microcirculation and significant hemorrhagic and ischemic phenomena. We have demonstrated that the administration of glucocorticosteroids at the specific doses and intervals can adequately replace the first (preparatory) injection of endotoxin. For this reason, we have attempted to experimentally simulate a frequent clinical situation, such as sepsis secondary to peritonitis, by intraperitoneal inoculation of Escherichia coli and hog gastric mucin into rats pretreated with dexamethasone. This inoculation was equivalent to the second injection of endotoxin in the Shwartzman model (triggering inoculation). A typical picture of disseminated intravascular coagulation induced by bacterial endotoxins developed, as demonstrated by the anatomopathologic, microbiologic, and hematologic studies performed. These results were then compared to those obtained in rats treated exclusively with dexamethasone or given, in addition, an effective antibiotic therapy.