RELATION BETWEEN SPINAL-CORD BLOOD-FLOW AND FUNCTIONAL RECOVERY AFTER BLOCKING WEIGHT-INDUCED SPINAL-CORD INJURY IN RATS

Spinal cord blood flow (SCBF) and motor performance on the inclined plane were measured up to 9 days after a reversible spinal cord compression injury in 49 Sprague-Dawley rats. A load of 35 g on 11 mm2 of the thoracic spinal cord for 5 minutes caused transient paraparesis with a decrease in the capacity angle on the inclined plane from 62 ± 1° (mean ± SEM) before injury to 33 ± 1° on Day 1, 45 ± 2° on Day 4, and 54 ± 3° on Day 9. SCBF was measured by the [14C]iodoantipyrine method, and in gray matter there was a decrease from 78.4 ± 2.3 ml/min/100 g of tissue in uninjured animals to 33.7 ± 1.5 ml/min/100 g of tissue on Day 1 after injury, increasing to 50.1 ± 2.0 on Day 4 and to 70.5 ± 2.7 ml/min/100 g of tissue on Day 9. At the corresponding times, the SCBF values in white matter were 14.5 ± 0.5, 6.7 ± 0.5, 10.2 ± 0.6, and 13.4 ± 0.6 ml/min/100 g of tissue, respectively. The animals in another group were loaded with 25 g for 5 minutes and on Day 1 exhibited a capacity angle of 43 ± 2° while the SCBF values for gray and white matter were 55.1 ± 2.0 and 11.1 ± 0.4 ml/min/100 g of tissue, respectively; thus, the results in this group were similar to the values on Day 4 in the animals loaded with 35 g. There was a significant linear correlation between SCBF in both gray and white matter, on the one hand, and the capacity angle on the other. This suggests that in this model, the disturbance in SCBF after spinal cord injury is related to the motor deficit in spinal cord function.