Tsuruga Mie, Taki Keiko, Ishii Genichiro, Sasaki Yurie, Furukawa Chiharu, Sugihara Takashi, Nomura Takaharu, Ochiai Atsushi, Magae Junji
Department of Bioengineering, Institute of Research and Innovation, 1201 Takada, Kashiwa, Chiba 227-0861, Japan.
Radiat Res. 2007 May;167(5):592-9. doi: 10.1667/RR0786.1.
Low-dose-rate radiation modulates various biological responses including carcinogenesis, immunological responses and diabetes. We found that continuous irradiation with low-dose-rate gamma rays ameliorated type II diabetes in db/db mice, diabetic mice that lack leptin receptors. Whole-body exposure of db/db mice to low dose-rate gamma radiation improved glucose clearance without affecting the response to insulin. Histological studies suggested that degeneration of pancreatic islets was significantly suppressed by the radiation. Insulin secretion in response to glucose loading was increased significantly in the irradiated mice. These results suggest that low-dose-rate gamma radiation ameliorates type II diabetes by maintaining insulin secretion, which gradually decreases during the progression of diabetes due to degeneration of pancreatic islets. We also inferred that protection from oxidative damage is involved in the anti-diabetic effect of low-dose-rate gamma rays because expression and activity of pancreatic superoxide dismutase were significantly elevated by low-dose-rate gamma radiation.
低剂量率辐射可调节多种生物学反应，包括致癌作用、免疫反应和糖尿病。我们发现，低剂量率伽马射线持续照射可改善db/db小鼠（缺乏瘦素受体的糖尿病小鼠）的II型糖尿病。将db/db小鼠全身暴露于低剂量率伽马辐射下可改善葡萄糖清除率，而不影响对胰岛素的反应。组织学研究表明，辐射可显著抑制胰岛的退化。照射后的小鼠对葡萄糖负荷的胰岛素分泌显著增加。这些结果表明，低剂量率伽马辐射通过维持胰岛素分泌来改善II型糖尿病，而胰岛素分泌在糖尿病进展过程中由于胰岛退化而逐渐减少。我们还推断，低剂量率伽马射线的抗糖尿病作用涉及对氧化损伤的保护，因为低剂量率伽马辐射可显著提高胰腺超氧化物歧化酶的表达和活性。
