Effect of ionizing radiation on caspase-3 protein expression in EL-4 cells in mice

Objective: To investigate the effect of ionizing radiation on caspase-3 protein expression of EL-4 cells. Methods: Mouse lymphoma EL-4 cell line was used. Flow cytometry (FCM) was used to examine caspase-3 protein expression and apoptosis. For dose-effect experiment, caspase-3 protein expression and apoptosis were measured 24 h after X-irradiation with doses of 0.5, 1.0, 2.0, 4. 0 and 6.0 Gy. For time course experiment, caspase-3 protein expression was measured at 2, 4, 8, 12, 24 and 72 h after 4.0 Gy X-irradiation. Results: In dose-effect experiment, it was demonstrated that the caspase-3 protein expression of EL-4 cells was increased significantly 24 h after X-irradiation with the doses of 0.5, 2.0, 4.0 and 6.0 Gy compared with sham-irrad (P<0.05 or P<0.01). It was also showed that apoptosis of EL-4 cells was induced significantly 24 h after X-irradiation with the doses of 0.5, 1.0 and 4.0 Gy compared with sham-irrad (P<0.05 or P<0.01). In time course experiment, the result showed that the caspase-3 protein expression of EL-4 cells was increased significantly 8, 12 and 24 h after 4.0 Gy X-irradiation compared with sham-irrad (P<0.01 or P<0.001). Conclusion: Caspase-3 protein expression and apoptosis in EL-4 cells could be induced by X-rays. (authors)