Posttraumatic Hypothermia Reduces Polymorphonuclear Leukocyte Accumulation Following Spinal Cord Injury in Rats

ABSTRACT The present study addresses the effects of moderate posttraumatic hypothermia (32°C) on the temporal and regional profile of polymorphonuclear leukocyte (PMNL) accumulation after traumatic spinal cord injury (SCI). We hypothesized that posttraumatic hypothermia would reduce the degree of inflammation by reducing PMNL infiltration. Rats underwent moderate spinal cord injury at T10 using the NYU impactor device. In the first study, the temporal profile of myeloperoxidase (MPO) activity (a marker of neutrophil accumulation) under normothermic (37°C) conditions was determined. The animals were allowed to survive for 3 or 24 h, or 3 or 7 days after SCI. Spinal cords were dissected into five segments rostral and caudal to the injury site. Additional animals were studied for the immunocytochemical visualization of MPO. In the second study, rats were sacrificed at 24 h after a monitoring period of normothermia (36.5°C/3 h) or hypothermia (32.4°C/3 h) with their controls. In the time course studies, MPO e...