N-cadherin at the glial scar in the rat

Following injury to the central nervous system (CNS), astrocytes become reactive and in many cases form a glial scar. Very little is known about the adhesive interactions between astrocytes at the glial scar, even though reactive gliosis and scar formation are a central issue in CNS wound healing. In the present study, we examine the role of cadherin in the process of scar formation using immunohistochemistry and immunoblot methods. When a stab wound was made in the cerebral cortex of the rat, cadherins were consistently upregulated by the reactive astrocytes at the glial scar. Our immunoblot analysis demonstrates that the increase in cadherin immunoreactivity was due to a threefold upregulation of a single protein with a molecular weight of 135 kDa. The size (135 kDa) and location of the immunoreactive protein at regions of cell-cell contact in cultured astrocytes indicates that the immunoreactive protein is N-cadherin. These data are the first to demonstrate that N-cadherin plays a prominent role in the response of astrocytes to injury, including the formation and maintenance of the glial scar.