Murine model for investigating severe trauma

The lack of a stable, easy-to-operate animal model for severe trauma has hindered the research progress. The aim of this study is to develop a mouse model that replicates the pathophysiological conditions of severe trauma, providing a reliable research tool.

Male C57BL/6J mice (aged 8-10 weeks and weighting approximately 20 g) were used to establish the severe trauma model. Under anesthesia, a midshaft femoral fracture was created and packed with sterile cotton. A midline incision was made from the inguinal region to the sternum, exposing the abdominal organs for 30 min. The right femoral artery was cannulated to induce controlled blood loss at 30%, 35%, 40%, and 50% of the total blood volume. Survival rates were monitored for 24 h post-induction. In the mice that experienced 30% blood loss, the mean arterial pressure, body temperature, blood gas parameters, peripheral blood inflammatory markers, and major organ pathological changes were assessed.

Mice with femoral fractures, soft tissue injuries, abdominal organ exposure, and 30% blood loss exhibited stable survival rates. Increased blood loss significantly reduced survival rates. Mean arterial pressure decreased initially, recovering within 0-15 min and returning to baseline by 50 min. Similarly, the body temperature decreased initially and gradually recovered to baseline within 50 min. Levels of peripheral blood inflammatory markers remained elevated for 12 h post-injury. Distant organs, including intestines, lungs, liver, spleen and kidneys, displayed varying degrees of injury.

The established mouse model replicates the pathophysiological responses to severe trauma, indicating stability and reproducibility, which could be an useful tool for further trauma research.