The occurrence of diffuse axonal injury in the brain: associated with the accumulation and clearance of myelin debris

The accumulation of myelin debris may be a major contributor to the inflammatory response after diffuse axonal injury. In this study, we examined the accumulation and clearance of myelin debris in a rat model of diffuse axonal injury. Oil Red O staining was performed on sections from the cerebral cortex, hippocampus and brain stem to identify the myelin debris. Seven days after diffuse axonal injury, many Oil Red O-stained particles were observed in the cerebral cortex, hippocampus and brain stem. In the cerebral cortex and hippocampus, the amount of myelin debris peaked at 14 days after injury, and decreased significantly at 28 days. In the brain stem, the amount of myelin debris peaked at 7 days after injury, and decreased significantly at 14 and 28 days. In the cortex and hippocampus, some myelin debris could still be observed at 28 days after diffuse axonal injury. Our findings suggest that myelin debris may persist in the rat central nervous system after diffuse axonal injury, which would hinder recovery.