Low-dose total-body γ irradiation modulates immune response to acute proton radiation
| Autor: | Asma Rizvi, Michael J. Pecaut, Daila S. Gridley, Xian Luo-Owen |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Blood Platelets
medicine.medical_specialty Erythrocytes CD3 Complex Lymphocyte Biophysics Spleen Granulocyte CD19 Antibodies Leukocyte Count Mice Immune system CD28 Antigens Internal medicine White blood cell medicine Animals Radiology Nuclear Medicine and imaging Irradiation Radiation biology business.industry Body Weight Immunity Dose-Response Relationship Radiation DNA Organ Size Lymphocyte Subsets Mice Inbred C57BL Dose–response relationship medicine.anatomical_structure Endocrinology Gamma Rays biology.protein Cytokines Female Protons Nuclear medicine business Whole-Body Irradiation |
| Zdroj: | Radiation research. 177(3) |
| ISSN: | 1938-5404 |
| Popis: | Health risks due to exposure to low-dose/low-dose-rate radiation alone or when combined with acute irradiation are not yet clearly defined. This study quantified the effects of protracted exposure to low-dose/low-dose-rate γ rays with and without acute exposure to protons on the response of immune and other cell populations. C57BL/6 mice were irradiated with ⁵⁷Co (0.05 Gy at 0.025 cGy/h); subsets were subsequently exposed to high-dose/high-dose-rate proton radiation (250 MeV; 2 or 3 Gy at 0.5 Gy/min). Analyses were performed at 4 and 17 days postexposure. Spleen and thymus masses relative to body mass were decreased on day 4 after proton irradiation with or without pre-exposure to γ rays; by day 17, however, the decrease was attenuated by the priming dose. Proton dose-dependent decreases, either with or without pre-exposure to γ rays, occurred in white blood cell, lymphocyte and granulocyte counts in blood but not in spleen. A similar pattern was found for lymphocyte subpopulations, including CD3+ T, CD19+ B, CD4+ T, CD8+ T and NK1.1+ natural killer (NK) cells. Spontaneous DNA synthesis by leukocytes after proton irradiation was high in blood on day 4 and high in spleen on day 17; priming with γ radiation attenuated the effect of 3 Gy in both body compartments. Some differences were also noted among groups in erythrocyte and thrombocyte characteristics. Analysis of splenocytes activated with anti-CD3/anti-CD28 antibodies showed changes in T-helper 1 (Th1) and Th2 cytokines. Overall, the data demonstrate that pre-exposure of an intact mammal to low-dose/low-dose-rate γ rays can attenuate the response to acute exposure to proton radiation with respect to at least some cell populations. |
| Databáze: | OpenAIRE |
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