Figure 1
The experimental timeline for the murine polytrauma (PT) with hemorrhagic shock (HS) model. All mice were randomly subjected to PT, HS, PT + HS, or sham-catherization procedures (N = 36; n = 8 per group, PT, HS, Sham; n = 7 per group, PT + HS). Untreated control mice (Ctrl, n = 5) are not shown here. Briefly, all mice were anaesthetized with 2.5–3% sevoflurane in oxygen. Ctrl animals were euthanized directly after induction of anesthesia. Mice in the PT and PT + HS groups were subjected to thoracic trauma/blunt bilateral chest trauma (TXT), closed head injury (TBI), and a distal femur fracture accompanied by soft tissue injury. At 20 min, mice in the Sham, HS, and PT + HS groups were catheterized in the left femoral artery to monitor blood pressure and induce sham procedures or HS; a jugular vein catheter was also inserted for reperfusion following blood loss. At the 80 min time point, mice in the HS and PT + HS groups were bled for 5–10 min to reach a mean arterial pressure (MAP) of 30 ± 5 mmHg which was kept stable for 60 min. At 140 min, mice in the HS and PT + HS groups were reperfused through the jugular vein with a balanced electrolyte solution over 30 min, using a fourfold volume calculation of the blood drawn to induce HS. Mice that failed to recover a MAP of 50 mmHg were additionally supported by a predetermined anesthesia adjustment and norepinephrine support protocol, by which the goal MAP of 50 mmHg was attained. MAP mean arterial pressure, NE norepinephrine, PT polytrauma, TBI traumatic brain injury, TXT thoracic trauma/blunt bilateral chest trauma.
