Thrombin stimulates fibrinogen-dependent cytokine and chemokine production in vivo.

Four days after TG administration, wild-type (+/+, ▪) or fibrinogen-deficient (−/−, ■) mice received intraperitoneal injections of thrombin (20 U). Macrophage numbers in peritoneal exudates were determined after 5 hours (left panel). Thrombin-stimulated macrophage activation was fibrinogen dependent (P < .001). Examination of the exudate fluid by ELISA revealed that thrombin also stimulated increases in peritoneal levels of MCP-1 (middle panel, P < .005) and IL-6 (right panel,P < .001) that were fibrinogen dependent (P < .005 and P < .001, respectively). The data represent averages and standard deviations of 4 animals per group. We repeated this experiment twice.