Abstract
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 (SCI) model using two different antibodies against ED1 and ionized calcium binding adaptor molecule 1 (Iba1). Male Sprague-Dawley rats were used to prepare the model. After anesthetizing, the animals were fixed on a surgical table and surgery was performed. A 2-mm-diameter metal rod weighing 30g was gently placed centrally onto the dura of the spinal cord on the dorsal side for 10min. Samples were obtained at 1 week, 4 weeks, 8 weeks and 12 weeks after SCI and compared with sham operated controls. For immunohistological examination, ED1 was used as a marker for macrophages and Iba1 was used as a marker for microglia. Immunohistochemical analysis was done by ABC Kit and fluorescent analysis was done by confocal laser scanning microscope. Results showed that activation was observed in both dorsal funiculus and ventral white matter area in spinal cord at 5mm rostral to the epicenter of injury. For both cells, there was a gradual increase in activation from 1 week to 4 weeks followed by down-regulation up to 12 weeks. We could stain macrophages by ED1 and microglia by Iba1. Macrophages may play a role in the phagocytosis of denatured dendrites after SCI, while microglia may have some cooperative functions since they were found scattered near macrophages. [Jpn J Physiol 55 Suppl:S203 (2005)]
