Response of circulating immune cells to major gunshot injury, haemorrhage, and acute surgery

Purpose: The purpose of this study was to use an established porcine model to investigate the effects on immune function of severe gunshot injury. Methods: Twelve pigs sustained two standardised rounds, one through right femur and one through left upper abdomen. First aid treatment and acute surgery was started immediately. Blood samples were drawn before shooting and after 75 min. Circulating neutrophils were isolated and reactive oxygen species (ROS) measured. Serum levels of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-10 were determined at 0, 75 min, as well as 2 h after incubation with 1 μg/ml endotoxin in an ex vivo whole blood model. Results: TNF-α, IL-1β, and IL-6 significantly increased at 75 min. ROS in circulating granulocytes tended to increase (NS). Incubation with endotoxin led to a more than 100-fold increase of TNF-α pre-trauma, compared to a three-fold increase post-trauma (p < 0.0001 between groups). A similar pattern was obtained for IL-1β, and IL-6. IL-10 was below detection in all samples. The granulocytes maintained their ability to react to the protein kinase C activator phorbol myristate acetate (PMA) after trauma. Conclusion: Severe gunshot injury and peritraumatic stress rapidly activate circulating immune cells, but reduce their capacity to react to a subsequent challenge to endotoxin.