Cortical expression of nuclear factor κB after human brain contusion

The aim of current study was to analyze the binding activity and the temporal and cellular expression of nuclear factor kappa B (NF-κB) in human contused brain. Eighteen contused brain samples were obtained from 17 patients undergoing surgery for brain contusions 5–80 h after trauma. NF-κB binding activity was detected by electrophoretic mobility shift assay (EMSA), and temporal and cellular expression of NF-κB subunits p65 and p50 was analyzed by immunohistochemistry. The results showed that a progressive upregulation of NF-κB activity occurred in the area surrounding the injured brain with the time from brain trauma to operation. The maximal expression of NF-κB was detected after 48 h postinjury. The expression of NF-κB p65 was mainly located at glial and vascular endothelial cells without expression at neurons. The expression of NF-κB p50 was mainly located at glial cells, a little at neurons and no expression at vascular endothelial cells. Within 24 h postinjury, both NF-κB p65 and p50 immunoreactivity was mainly observed in the nucleus of cells. After 24 h postinjury, NF-κB p65 labeling was found in the both nucleus and cytoplasm of glial and endothelial cells; otherwise, p50 labeling was primarily found in the nucleus of glial cells and in the nucleus, cytoplasm and process of neurons. It is concluded that NF-κB could be highly upregulated at human contused brain and the cellular pattern of p65 and p50 expression might be closely associated with the cell functions.