CHARACTERIZATION OF AXONAL ULTRASTRUCTURAL PATHOLOGY FOLLOWING EXPERIMENTAL SPINAL-CORD COMPRESSION INJURY

The present study characterizes axonal pathology associated with traum atic compression injuries of the spinal cord and quantitatively assess es subtypes of axonal pathology in the acute, post-injury period. Eigh teen adult female Wistar rats underwent spinal cord compression injury with a 53 g modified aneurysm clip at the C-g-T-1 segment. Six additi onal rats served as sham controls. Six experimental animals were sacri ficed at each of the three post-injury time points: 15 min, 2 h and 24 h. From all animals, the C-g-T-1 spinal cord was dissected and proces sed for both light and electron microscopy. Axonal pathology included periaxonal swelling, organelle accumulation, vesicular myelin, myelin invagination, myelin rupture, and giant axons. Early myelin rupture an d the ultrastructural features of giant axons are described here for t he first time in the context of spinal cord compression injury. The qu antitative analysis characterizes the prevalence of types of axonal pa thology over the acute post-injury period and provides evidence for th e secondary injury hypothesis regarding the evolution of axonal pathop hysiology following trauma.