Response of lysosomal hydrolases of dog spinal cord and cerebrospinal fluid to experimental trauma

Abstract

Spinal cord damage was induced' in dogs by a 400 gm-centimeter force injury to assess an early release of lysosomal enzymes from traumatized cord. In whole cord homogenates, an early decrease in total acid phosphatase and beta-glucuronidase was observed, approaching control levels by 2 hours. With acid phosphatase, total activity increased to 11 7 percent of control by 4 hours. Beta-glucuronidase showed no significant change in free activity at any time up to 4 hours. Dissected gray and white matter trauma samples displayed free, soluble, and total activities similar to controls. Cisternal CSF showed increased beta-glucuronidase and acid phosphatase activity at 30 and 60 minutes, while lumbosacral values were decreased. By 2 hours, acid phosphatase was increased in lumbar fluid and remained elevated for the 24-hour interval studied. Cisternal CSF protein was unchanged throughout the 24-hour period, while lumbosacral values increased at 4 and 24 hours. In traumatized adjacent and control cord segments a significant drop in total acid phosphatase activity in the trauma core samples was noted by 30 minutes and remained lower than control for the 24-hour period. The early drop in total activity in the area of maximal injury suggests enzyme inactivation by free radicals or some unknown inhibitor. The late increase in acid phosphatase activity in surrounding white matter may be due to accumulation of lysosomes within axis cylinders of partially injured nerve fibers. We conclude that lysosomal enzyme release does not appear to play a role in the early phases of the pathophysiologic process of spinal cord trauma.