The Effect of Distal Aortic Pressure on Spinal Cord Perfusion in Rats

BACKGROUND: Aortic cross clamping is associated with spinal cord ischemia. This study used a rat spinal cord ischemia model to investigate the effect of distal aortic pressure on spinal cord perfusion. MATERIALS AND METHODS: Male Sprague-Dawley rats (n=12) were divided into three groups. In group A (n=4), the aorta was not occluded. In groups B (n=4) and C (n=4), the aorta was occluded. In group B the distal aortic pressures dropped to around 20 mmHg. In group C, the distal aortic pressure was decreased to near zero. The carotid artery and tail artery were cannulated to monitor the proximal aortic pressure and the distal aortic pressure. Fluorescent microspheres were used to measure the regional blood flow in the spinal cord. RESULTS: After aortic occlusion, blood flow to the cervical spinal cord showed no significant difference among the three groups. In groups B and C, the thoracic and lumbar spinal cord and renal blood flow decreased. No microspheres were detected in the thoracic and lumbar spinal cord of group C. CONCLUSION: The spinal cord blood flow is dependent on the distal aortic pressure after thoracic aortic occlusion.