Spinal cord blood flow measured with microspheres following spinal cord injury in the rat

A decrease in spinal cord blood flow (SCBF) is a known sequela of spinal cord injury. The radioactive microsphere technique permits repeated measurement of spinal cord blood flow (SCBF) and cardiac output (CO) in the same experimental animal. The purpose of this study was to adapt the radioactive microsphere technique for use in the rat extradural clip compression injury model used in our laboratory. Thirteen adult Wistar rats were anaesthetized and ventilated. Mean systemic arterial pressure (MSAP) was recorded continuously. Control animals (n = 8) did not have a surgical procedure whereas the injured animals (n = 5) underwent a C7-T1 laminectomy followed by a one minute, 50 gram extradural clip compression injury at T1. Radioactive microspheres were used for two blood flow and CO determinations in both groups. MSAP fell 59% in the injured animals (p less than 0.01), but this was not accompanied by significant changes in heart rate or CO. There was a 50% reduction in SCBF in the injured cord (p less than 0.02), and there were significant reductions in cerebral blood flow (p less than 0.05) and cerebellar blood flow (p less than 0.02) following spinal cord injury.