Polymorphonuclear leucocyte activation after trauma: evidence for increased generation of oxygen free radicals in response to in vitro endotoxin stimulation.

The effects of moderate bone trauma on the functional status of circulating polymorphonuclear neutrophil (PMN) leucocytes were studied over a 3-day period in a porcine model. Nine pigs were submitted to femur marrow nailings and six acted as controls. The PMNs were studied in regard to production of oxygen free radicals and locomotion. The trauma was followed by leucocytosis, dominated by granulocytosis. Oxygen free radical production by PMNs, measured by chemiluminescence, was significantly greater in the traumatized animals than in the controls. Stimulation of the PMNs with low concentrations of endotoxin disclosed intergroup differences until 48 hours post-trauma. No intergroup difference in PMN locomotion were demonstrated. The results indicated post-traumatic functional changes in the circulating PMNs, suggesting increased reactivity and sensitivity for gram-negative bacteria and their endotoxins during septicaemia.