Effects of whole-body irradiation with X-rays on apoptosis in mouse splenocytes and peritoneal macrophages

Objective: To study the effects of whole-body irradiation (WBI) with different doses of X-rays on apoptosis in mouse splenocytes and peritoneal macrophages. Methods: The apoptosis percentages of mouse splenocytes and peritoneal macrophages were detected with flow cytometry (FCM) at different time after the whole-body X-irradiation using the staining of Annexin-V and PI. Results: As compared with the control, the percentage of apoptosis in mouse splenocytes began to increase gradually 24 h after WBI with 2 Gy X-rays (P< 0.05), and the percentage of apoptosis in mouse peritoneal macrophages arose 4 h after 2 Gy irradiation, and kept higher level till 48 h (P<0.05, P<0.01, P<0.001). After WBI with 0.075 Gy X-rays, the percentage of apoptosis in mouse splenocytes reduced at 24 h (P<0.05), and the percentage of apoptosis in peritoneal macrophages significantly reduced from 2 h to 16 h (P<0.05) as compared with the control. Conclusion: High dose irradiation can stimulate apoptosis in mouse splenocytes and peritoneal macrophages, while low dose irradiation can cause an opposite effect and even suppress immunocyte apoptosis. (authors)