Contribution of inflammation to cellular injury in compartment syndrome in an experimental rodent model

Compartment syndrome, a devastating consequence of limb trauma, is characterised by severe tissue injury and microvascular perfusion deficits. We hypothesised that leucopenia might provide significant protection against microvascular dysfunction and preserve tissue viability. Using our clinically relevant rat model of compartment syndrome, microvascular perfusion and tissue injury were directly visualised by intravital video microscopy in leucopenic animals. We found that while the tissue perfusion was similar in both groups (38.8% (standard error of the mean (sem) 7.1), 36.4% (sem 5.7), 32.0% (sem 1.7), and 30.5% (sem 5.35) continuously-perfused capillaries at 45, 90, 120 and 180 minutes compartment syndrome, respectively versus 39.2% (sem 8.6), 43.5% (sem 8.5), 36.6% (sem 1.4) and 50.8% (sem 4.8) at 45, 90, 120 and 180 minutes compartment syndrome, respectively in leucopenia), compartment syndrome-associated muscle injury was significantly decreased in leucopenic animals (7.0% (sem 2.0), 7.0%, (sem 1.0), 9.0% (sem 1.0) and 5.0% (sem 2.0) at 45, 90, 120 and 180 minutes of compartment syndrome, respectively in leucopenia group versus 18.0% (sem 4.0), 23.0% (sem 4.0), 32.0% (sem 7.0), and 20.0% (sem 5.0) at 45, 90, 120 and 180 minutes of compartment syndrome in control, p = 0.0005). This study demonstrates that the inflammatory process should be considered central to the understanding of the pathogenesis of cellular injury in compartment syndrome.