Different expression of macrophages and microglia in rat spinal cord contusion injury model at morphological and regional levels.

Macrophages and microglia are implicated in spinal cord injury, but their precise role is not clear. In the present study, activation of these cells was examined in a spinal cord injury model using 2 different antibodies against ED1 clone and ionized calcium binding adaptor molecule 1 (Iba1). Activation was observed at 1, 4, 8, and 12 weeks after contusion injury and was compared with sham operated controls. Our results indicate that activation could be observed in both the dorsal funiculus and the ventral white matter area in the spinal cord at 5 mm rostral to the epicenter of injury. For both cells, there was a gradual increase in activation from 1-4 weeks, followed by down-regulation for up to 12 weeks. As a result, we could stain macrophages by ED1 and microglia by Iba1. We concluded that macrophages may play a role in the phagocytosis of denatured dendrites after spinal cord injury, while microglia may have some cooperative functions, as they were found scattered near the macrophages.