Decreased incidence of thymic lymphoma in AKR mice as a result of chronic, fractionated low-dose total-body X irradiation.
We have investigated whether low-dose total-body X irradiation could suppress the development of lymphoma in AKR mice. Male mice were irradiated with 5 cGy three times a week or 15 cGy two times a week from 11 weeks of age for 40 weeks. The incidences of lymphoma were 80.5% in sham-irradiated mice, 67.5% in mice irradiated with 5 cGy three times a week and 48.6% in mice irradiated with 15 cGy twice a week. Incidence of lymphoma was significantly reduced by irradiation with 15 cGy twice a week (P = 0.006). The mean survival time was significantly prolonged from 283 +/- 3 days in control mice to 316 +/- 10 days in mice irradiated with 15 cGy twice a week (P = 0.008) and to 309 +/- 14 days in mice irradiated with 5 cGy three times a week (P = 0.040). Because about 80% of male AKR mice die of lymphoma, it is likely that the prolonged life span observed in the irradiated mice is due to the reduced incidence of lymphoma.
Ishii
K
K
Department of Radiology, Tohoku University School of Medicine, Sendai, Japan.
Hosoi
Y
Y
Yamada
S
S
Ono
T
T
Sakamoto
K
K
D000818:Animals; D008223:Lymphoma / Q000517:prevention & control*; D008297:Male; D051379:Mice; D008806:Mice, Inbred AKR; D013953:Thymus Neoplasms / Q000517:prevention & control*; D014916:Whole-Body Irradiation