The Effect of Irradiation and Methylprednisolone in Spinal Cord Injured Rats

Study Design. This study investigated the outcome of combined therapy with irradiation and methylprednisolone (MP) after a traumatic spinal cord injury (SCI). Objective. To evaluate the neurologic outcomes as well as the antiapoptotic and anti-inflammatory effects on traumatic SCI in rats after combined therapy. Summary of Background Data. Although irradiation carries the risk of secondary SCI, it has been effective for the regeneration of the axons of nerve cells by reducing gliosis. Thus, to minimize apoptosis and irradiation risks after SCI, this study investigated the effects of steroid injections before irradiation. Methods. Thirty-two rats were used for the experimental procedure. After a traumatic SCI, they were divided into 4 groups of 8 rats each: (1) a control group that only had rats with a SCI (Group 1); (2) a group that received MP at 30 minutes, 6 hours and 24 hours, and then received irradiation 2 days after the SCI (Group 2); (3) a group that received MP at 30 minutes, and irradiation 2 days after the SCI (Group 3); and (4) a group that received irradiation 2 days after the traumatic SCI (Group 4). Results. The degree of recovery using the inclined plane climbing test was greatest in Group 2, followed by Group 3, Group 4, and Group 1. The cavitation lesions, Terminal Deoxynucleotidyl Transferase dUTP Nick End Labeling -positive apoptosis, glial fibrillary acidic protein-positive astrocyte count, and CC-1-positive oligodendrocyte count significantly decreased in the irradiated groups (Groups 2, 3, 4) compared to the control group (Group 1). In particular, they decreased considerably more in the group that received MP 3 times (Group 2) compared to the group that received MP only once (Group 3). Conclusion. These results suggest that the combined therapy was effective and might provide synergistic effects for neurologic recovery after a traumatic SCI.