Superoxide radicals play important roles in the pathogenesis of spinal cord injury.

To investigated a possible role of superoxide dismutase (SOD) in the pathogenesis of spinal cord injury (SCI), the change in the circulatory status in an experimental SCI model of rats was examined. The blood pressure (BP) of the SCI group decreased markedly by compression or head-up-tilt (60 degrees). The extent of the BP decrease was diminished by the administration of along acting SOD (SM-SOD) prior to injury. Compression, tilting and the administration of SM-SOD increased the sensitivity of resistant arteries to acetylcholine. SM-SOD treated rats had a significantly lower mortality than was found in untreated rats. These findings indicate that superoxide radicals may contribute to the pathogenesis of spinal cord injury and orthostatic hypotension caused by SCI.