title: Suppressing effect of low-dose gamma-ray irradiation on collagen-induced arthritis.
abstract: We previously reported attenuation of autoimmune disease by low-dose gamma-ray irradiation in MRL-lpr/lpr mice. Here, we studied the effect of low-dose gamma-ray irradiation on collagen-induced arthritis (CIA) in DBA/1J mice. Mice were immunized with type II collagen, and exposed to low-dose gamma-rays (0.5 Gy per week for 5 weeks). Paw swelling, redness, and bone degradation were suppressed by irradiation, which also delayed the onset of pathological change and reduced the severity of the arthritis. Production of tumor necrosis factor-alpha, interferon-gamma, and interleukin-6, which play important roles in the onset of CIA, was suppressed by the irradiation. The level of anti-type II collagen antibody, which is essential for the onset of CIA, was also lower in irradiated CIA mice. The population of plasma cells was increased in CIA mice, but irradiation blocked this increase. Since regulatory T cells are known to be involved in suppression of autoimmune disease, the population of CD4(+)CD25(+)Foxp3(+) regulatory T cells was measured. Intriguingly, a significant increase of these regulatory T cells was found in irradiated CIA mice. Overall, our data suggest that low-dose gamma-ray irradiation could attenuate CIA through suppression of pro-inflammatory cytokines and autoantibody production, and induction of regulatory T cells.
authors.affiliation: Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nakatsukasa
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Tsukimoto
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ohshima
authors.forename: Fumitoshi
authors.initials: F
authors.lastname: Tago
authors.forename: Ayako
authors.initials: A
authors.lastname: Masada
authors.forename: Shuji
authors.initials: S
authors.lastname: Kojima
mesh_terms: D000818:Animals; D001168:Arthritis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy*; D024043:Collagen Type II; D016207:Cytokines / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D011879:Radiotherapy Dosage; D016896:Treatment Outcome
chemical_list: D024043:Collagen Type II; D016207:Cytokines