Mechanism of the congestion of lymph nodes induced by ellagic acid in rats.

Intravenous injection of ellagic acid (EA, 30 mg/Kg), an activator of the Hageman factor, induced congestion of lymph nodes and dilatation of the spleen in rats. The dilatation of the spleen was inhibited by heparin, thrombin, defibrase, clocoumarol, lambda carrageenan, SBTI, PCR 4099 and CCI 17810. The congestion of lymph nodes was inhibited by heparin, thrombin, defibrase, clocoumarol, SBTI, lambda carrageenan, aspirin, indomethacin and ketoprofen, phentolamine and hexamethonium. Thrombin, defibrase, lambda carrageenan did not induce any congestion of the lymphoid tissues. These results suggest the the dilatation of the spleen induced by ellagic acid would result from blood coagulation, platelet stimulation and kinin formation. The congestion of lymph nodes would depend on kinins, blood coagulation and prostaglandin;s. The activation of Hageman factor in acute inflammatory reactions could mediate the early congestion of lymph nodes.