Spatiotemporal patterns and essential role of TNF receptor-associated factor 5 expression after rat spinal cord Injury.

TRAF5 (TNF receptor-associated factor 5), which has a tumor necrosis factor receptor-associated factor (TRAF) domain in its carboxyl terminus, was identified CD40-associated factor. It was a signal transducer for NF-κB signal pathway and other pathway. To elucidate the expression and roles of TRAF5 in nervous system lesion and repair, we performed an acute spinal cord injury (SCI) model in adult rats and studied the dynamic changes of TRAF5 expression in spinal cord. Western blot and immunohistochemistry analysis revealed that TRAF5 was present in normal spinal cord. It gradually increased, reached a peak at 5 days after SCI, and then declined during the following days. Immunofluorescence double-labeling revealed that TRAF5 was co-expressed with NeuN and GFAP, respectively. Interesting, after injury, TRAF5 expression was increased predominantly in astrocytes, which highly expressed PCNA, a marker for proliferating cells. In conclusion, this is the first description of TRAF5 expression in spinal cord. Our data suggested that TRAF5 might play important roles in CNS pathophysiology after SCI.