Figure 2

Macrophages/microglia in the human spinal cord after traumatic injury. Images were taken from control spinal cords and cases with different survival times after SCI in transverse sections stained with the CD68 antibody. A: In a control spinal cord, CD68 immunohistochemistry reveals bipolar peri-vascular cells (arrow). B: Two days after SCI, sections from the lesion site demonstrated a clear up-regulation of CD68-positive cells. Round to oval shaped cells (arrows) were spread over the area. C: In the same case, areas of bleeding contained some round immunopositive macrophages (arrows). The diffuse brown background staining was unspecific, being due to the high concentration of endogenous peroxidase in the blood cells. D: 4 days after injury, the lesion area displayed an increased number of CD68-positive cells, many with activated microglial and rounded macrophage-like morphologies. E: In the peri-lesional gray matter of the same case, identifiable neurons (arrowheads) were often closely surrounded by CD68 positive cells. F: 10 days after injury, the lesion epicentre was filled with numerous microglia/macrophages. G: 24 days after injury, the lesion epicentre was heavily loaded with large, foamy macrophages. H: Four months after SCI, only few immunoreactive cells can be seen at the site of injury. (A-H, mag. ×260)