title: Effect of extended exposure to low-dose radiation on autoimmune diseases of immunologically suppressed MRL/MpTn-gld/gld mice.
abstract: The purpose of this paper is to analyze the relationship between alterations of splenic T-cell subpopulations and the amelioration of autoimmune diseases of MRL/MpTn-gld/gld mice (MRL/gld mice) after extended exposure to low-dose radiation. After the onset of disease, 4-month-old MRL/gld mice were exposed to doses of 0.05, 0.2, and 0.5 Gy/day for 4 weeks (5 days/week), for total doses of 1, 4, and 10 Gy, respectively. The MRL/gld mice that were irradiated with 0.2 and 0.5 Gy/day showed an obvious decrease in the proportion of splenic CD4(-)CD8(-) T cells and remission of their autoimmune diseases. After the last irradiation, apoptotic cells were found in the white pulp of the spleen of the MRL/gld mice irradiated with 0.2 Gy/day, but not in the MRL/MpJ-+/+ mice (MRL/wild mice), which experienced a similar treatment. Before the onset of disease, 3-month-old MRL/gld mice subjected to 0.2 Gy/day showed a decrease in the proportion of splenic CD4(-)CD8(-) T cells and less remission of their autoimmune diseases than the 4-month-old mice. These results suggest that the accumulated CD4(-)CD8(-) T cells are more sensitive to radiation than other T-cell subpopulations, and that decreasing CD4(-)CD8(-) T cells with extended exposure to low-dose radiation leads to the amelioration of autoimmune disease.
authors.affiliation: Department of Radiation Biology and Health, University of Occupational and Environmental Health, Japan. aootsuya@med.uoeh-u.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Ootsuyama
authors.forename: Ryuji
authors.initials: R
authors.lastname: Okazaki
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Norimura
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D001327:Autoimmune Diseases / Q000276:immunology / Q000473:pathology* / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D051379:Mice; D011879:Radiotherapy Dosage; D013154:Spleen / Q000276:immunology / Q000473:pathology* / Q000528:radiation effects*; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology* / Q000528:radiation effects*; D016896:Treatment Outcome; D014916:Whole-Body Irradiation / Q000379:methods*