Increase of oligodendrocyte progenitor cells after spinal cord injury

The reaction of oligodendrocyte progenitor cells (OPCs) after spinal cord i njury (SCI) is poorly understood. In this study, we examined oligodendrogli al reactions after contusion SCI in adult rats by immunohistochemistry. OPC s were identified by staining with monoclonal antibodies (mAbs) A2B5 and O4 . Each of the A2B5-, O4-positive OPCs and galactocerebroside-positive oligo dendrocytes dramatically increased in the lesion of the dorsal posterior fu niculus. Bromodeoxyuridine (BrdU) incorporation studies showed that most O4 -positive cells in the lesion were labeled with BrdU, suggesting that these OPCs were proliferative. In contrast, the expression of myelin basic prote in was decreased in the lesion compared with controls that received laminec tomy only. From the injured cord, OPCs were isolated by immunopanning with mAb A2B5. We observed an increased number of OPCs from the injured spinal c ords compared with those isolated from controls and unoperated animals. Aft er several days in culture, the OPCs from the lesion expressed galactocereb roside. These results suggest that OPCs are induced and can differentiate f ollowing SCI in the adult rat. J. Neurosci. Res. 65:500-507, 2001. (C) 2001 Wiley-Liss, Inc.