Effects of dexamethasone on apoptosis-related cell death after spinal cord injury

Object. The purpose of this study was to analyze the expression of F7-26 (Apostain) in injured spinal cord tissue, and the modifying effects of dexamethasone administration. Methods. A total of 56 adult female Wistar rats were subjected to traumatic spinal cord injury (SCI) to induce complete paraplegia. These rats were divided into two groups according to whether they received dexamethasone (doses of 1 mg/kg daily) post-SCI. Injured spinal cord tissue was studied by means of conventional histological techniques, and Apostain expression was determined by immunohistochemical analysis at 1, 4, 8, 24, and 72 hours, and at 1 and 2 weeks after SCI in all the animals. Apostain-positive cells, mainly neurons and glial cells, were detected 1 hour after injury, peaking at 8 hours, after which the number decreased. One week after injury, apoptosis was limited to a few glial cells, mainly oligodendrocytes, and 2 weeks after injury there was no evidence of Apostain-positive cells. In the group of paraplegic rats receiving post-SCI intraperitoneal dexamethasone, there was a significant decrease in the number of Apostain-positive cells. Conclusions. Analysis of the results indicated that apoptosis plays a role in the early period after SCI and that administration of dexamethasone decreases apoptosis-related cell death in the injured spinal cord tissue.