Presence and significance of CD-95 (Fas/APO1) expression after spinal cordinjury

Object. A glycoprotein. CD95 (Fas/APO1) is widely considered to be implicat ed in the development of apoptosis in a number of tissues. Based on the hyp othesis that apoptosis is related to cell death after spinal cord injury (S CI), the authors studied the presence and distribution of CD95 (Fas/APO1)-p ositive cells in injured spinal cord tissue for the purpose of determining the significance of this protein during the early phases of SCI. Methods. The presence and distribution of cells showing positive immunostai ning for CD95 (Fas/APO1) were studied 1, 4, 8, 24, 48, and 72 hours and 1, 2, and 4 weeks after induction of experimental SCI in rats. Studies were co nducted using a monoclonal antibody to the CD95 (Fas/APO1) protein. Positiv ity for CD95 (Fas/APO1) was observed in apoptotic cells, mainly in the gray matter, 1 hour after trauma, and the number of immunostained cells increas ed for the first 8 hours, at which time the protein was expressed in both g ray and white matter. From 24 to 72 hours postinjury, the number of immunos tained cells decreased in the gray matter, but increased in the white matte r. From then on, there were fewer CD95 (Fas/APO1)-positive cells, but some cells in the white matter still exhibited positive immunostaining 1 and 2 w eeks after injury. At 3 weeks, there remained no CD95 (Fas/APO1)-positive c ells in injured spinal cord. Conclusions. These findings indicate that CD95 (Fas/APO1) is expressed afte r SCI, suggesting a role for this protein in the development of apoptosis a fter trauma and the possibility of a new therapeutic approach to SCI based on blocking the CD95 (Fas/APO1) system.