Detection of platelet-activating factor during traumatic shock.

The purpose of this study was to determine if platelet-activating factor (PAF) is formed in the peritoneal fluid of rats following traumatic shock. Anesthetized rats subjected to Noble-Collip drum trauma developed a lethal shock state characterized by a mean survival time of 80 +/- 16 min and a final mean arterial blood pressure of 54 +/- 7 mm Hg compared with 117 +/- 14 mm Hg in sham-shock control rats. Peritoneal fluid from traumatized and PAF-infused rats analyzed by high performance liquid chromatography (HPLC) contained a phospholipid which had a similar retention time as authentic PAF, but was absent in sham shock rats. Furthermore, aliquots of this chromatographic peak aggregated washed rabbit platelets, and the aggregation was blocked by a specific PAF receptor antagonist, CV-6209. Moreover, extraction of peritoneal fluid from traumatized rats aggregated washed rabbit platelets and this activity increased nearly four-fold in traumatized rats compared to sham shock rats. These findings are consistent with the formation of PAF in traumatic shock, and along with previous data of PAF antagonists ameliorating traumatic shock, support a role of platelet-activating factor in the pathogenesis of traumatic shock.