Megakaryocyte activation and mobilization from the bone marrow in response to trauma and hemorrhagic shock in mice

Severe injuries result in acute changes in platelet number and function, but the impact of trauma and hemorrhagic shock on megakaryocytes (MKs) in the initial hours after injury have not been studied in detail. Using a murine model of trauma-hemorrhage, we identified rapid changes in MK morphology and mobilization into bone marrow sinusoids, changes that were detectable within one hour. Levels of several alpha-granule derived proteins were elevated in the bone marrow, and co-culture of naive MKs with bone marrow supernatant from injured mice resulted in similar changes to those observed in the model. These results illustrate that trauma-hemorrhage results in a hyperacute alteration in the bone marrow micro-environment that alters MK activity within an hour of injury.