The Effects of Nimodipine on Irradiation-Induced Apoptosis in the Rat Spinal Cord

ABSTRACT

OBJECTIVE: Radiation therapy is an effective adjunctive therapy in the management of brain and spinal cord tumors. The damage to normal tissue, however, has been often the dose-limiting factor in radiation therapy. The purpose of this study is to see whether nimodipine, the one of calcium channel blockers, is effective for the prevention of irradiation-induced apoptosis in the rat spinal cord. METHODS: Sprague-Dawley rats were used Control(n=12), Nimodipine-treated(0.5mg/kg, n=12). After nimodipine was administered intraperitoneally, the spinal cord of cervicothoracic junction was exposed to a single 10Gy dose of gamma rays using Ir-192. All spinal cords underwent histological examination at 4, 8, and 12 hours after irradiation, and apoptotic cells were detected by TUNEL assay and were determined by direct visual counting at magnification of x200. RESULTS: On the standard H-E stain, little evidence of histopathological change was noted within the 12 hours after irradiation. Both groups showed gradual increase of apoptotic cell counts with the lapse of time. But, in nimodipine-treated group, apoptotic cell counts were reduced significantly, compared to those of control group after irradiation, especially at 8 and 12 hours. CONCLUSION: The results suggest that nimodipine may have effects on the prevention of radiation-induced apoptosis in the spinal cord.