In
polytrauma patients a thoracic
trauma is one of the most critical
injuries and an important trigger of post-traumatic
inflammation. About 50% of patients with thoracic
trauma are additionally affected by
bone fractures. The risk for
fracture malunion is considerably increased in such patients, the pathomechanisms being poorly understood. Thoracic
trauma causes regional alveolar
hypoxia and, subsequently,
hypoxemia, which in turn triggers local and systemic
inflammation. Therefore, we aimed to unravel the role of
oxygen in impaired bone regeneration after thoracic
trauma. We hypothesized that short-term breathing of 100%
oxygen in the early post-traumatic phase ameliorates
inflammation and improves bone regeneration. Mice underwent a femur
osteotomy alone or combined with blunt chest
trauma 100%
oxygen was administered immediately after
trauma for two separate 3 hour intervals. Arterial blood gas tensions, microcirculatory perfusion and oxygenation were assessed at 3, 9 and 24 hours after injury. Inflammatory
cytokines and markers of oxidative/nitrosative stress were measured in plasma, lung and fracture
hematoma. Bone healing was assessed on day 7, 14 and 21. Thoracic
trauma induced pulmonary and systemic
inflammation and impaired bone healing. Short-term exposure to 100%
oxygen in the acute post-traumatic phase significantly attenuated systemic and local inflammatory responses and improved fracture healing without provoking toxic side effects, suggesting that
hyperoxia could induce anti-inflammatory and pro-regenerative effects after severe injury. These results suggest that breathing of 100%
oxygen in the acute post-traumatic phase might reduce the risk of poorly healing fractures in severely injured patients.