[Immunohistochemical study of apoptosis in the cells of experimental injured spinal cord].

We studied the temporal and spatial profile of apoptosis following acute spinal cord (SC) injury in rats and influence of chicken yolk transplantation on the programmed cell death. 18 female rats were subjected to complete SC transsection with removal of three millimeters of the SC at the level of the ninth thoracic vertebra. The gap was filled with denaturated chicken yolk in 9 animals. 9 control rats had no transplantation. Temporal and spatial course of apoptosis was estimated in longitudinal sections of the SC by TUNEL assay technique 4 hours, 3 days, 2 weeks, 40 days and 3 months after the injury. Apoptosis occurred through all posttraumatic period with its peak 40 days after the injury and decreased slowly to the minimal level by the third month. Apoptotic cells appeared near the site of the injury immediately after the trauma along the cord several hours later. Apoptosis involved only glial cells, neurons had no apoptotic signs. Suppression of apoptosis occurred in the yolk transplantation group and was accompanied by greater number of neuronal and glial survivals. Thus, apoptotic glial death after transsection of the SC in rats occurred mainly for the first eight weeks along the whole spinal cord.