A biochemical investigation of spinal cord after contusive injury

A closed spinal cord contusive injury system which is easily and reproducibly inflicted is described. At various times after injury, homogenates from individual segments along the cord were evaluated for total protein, lipid soluble galactose, (galactolipid), ceramide, 2′,3′-cyclic nucleotide 3′-phosphohydrolase, and myelin. Homogenates and myelin were also evaluated by SDS-polyacrylamide gel electrophoresis. In addition, the tissues were evaluated by light and electron microscopy. The results indicated that there was little change, in comparison with normal spinal cord tissue, in any biochemical components studied as long as 48 h after contusive injury. This was especially evident when the data were normalized on the basis of protein and/or galactolipid per tissue slice. This was in marked contrast to the progressive tissue necrosis and unraveling of the myelin sheath evident by light and electron microscopic examination of the injury site. The data suggest that at short times after injury, the architecture of the myelin sheath is disorganized yet the biochemical building blocks are still present.