132 A Novel Murine Model of Burn-Induced Platelet Dysfunction

Abstract

Abstract Introduction Platelet dysfunction has been demonstrated as a part of burn induced coagulopathy (BIC), however, the etiology and clinical significance are unknown. Determining the etiology and clinical significance of BIC platelet dysfunction is difficult in humans due to heterogeneity of injuries and treatment. The goal of this study was to develop a murine model of BIC burn-induced platelet dysfunction to allow for high-throughput investigation of the mechanisms and the possible effects platelet dysfunction has on burn outcomes. Methods Using an established murine model of burn injury, we investigated plasma and cellular markers of BIC. Under adequate anesthesia and analgesia six-week-old C57BL6/J mice were administered a ~30% TBSA dorsal burn by scalding. Sham animals received identical preparation and resuscitation without the burn injury. Blood was collected at 6-, 24-, and 48-hours post-burn for measurement of platelet function, and plasma was isolated for protein measurements of coagulopathy (N=5 per group per time point). Results Like findings in humans, mice exhibited systemic markers of BIC (excess coagulation, fibrinolysis, and inflammation) within the first 6–24 hours post-burn. Platelets in whole blood were treated with platelet agonists ADP and PAR4-activating peptide (PAR4AP), and markers of platelet signaling and function (P-selectin expression and GpIIb/IIIa activation) were measured by flow cytometry. At 6 hours post-procedure, platelets from burn mice exhibited a slight, insignificant increase in markers of activation and response to stimulation compared with platelets from sham mice. At 24 hours post-burn, burn mice exhibited a significant decrease in platelet count (P< 0.02) and platelet function indicated by reduced GpIIb/IIIa activation (P< 0.01) and P-selectin expression (P< 0.05)in response to ADP and PAR4-AP compared with sham mice. Platelet function began to return at 48 hours post-burn with no significant difference between groups. Conclusions Platelet loss and dysfunction occur after burn injury, but the consequence of these effects is not well understood. The findings in this study are consistent across multiple experiments and resembled platelet dysfunction observed in different human traumatic injuries, validating the murine model as an inexpensive and efficient model of human injury in which to study platelet defects and the molecular mechanisms driving them.