Unno Tatsuya, Hashimoto Mitsuyasu, Arai Shoichi, Kurosawa Mieko
Basic Medical Research Center, International University of Health and Welfare, Otawara, Tochigi, Japan.
Auton Neurosci. 2002 Mar 18;96(2):119-25. doi: 10.1016/s1566-0702(02)00006-1.
Radiotherapy for malignant tumours often elicits anorexia or loss of appetite as an adverse effect. However, the mechanism for this is poorly understood. The present study was undertaken to investigate if visceral afferents are responsible for reduction of food intake following X-ray irradiation. Rats were exposed bilaterally to X-ray (10 MV) irradiation with total doses of 1.5, 3 and 6 Gy, using a high-energy electron linear accelerator at a dose rate of 4.9 Gy min(-1) X-ray irradiation of the whole body, abdomen or head with doses of 1.5, 3 and 6 Gy reduced food intake in a dose-dependent manner. The reduction of food intake after X-ray irradiation of the whole body or abdomen was significantly greater than when only the head was irradiated. Reduction of food intake was observed for the first 4 days after 6 Gy X-ray irradiation of the abdomen, while it was observed only on the first day after the same 6-Gy irradiation of the abdomen in animals whose small-diameter afferents were ablated by capsaicin pre-treatment. These results suggested that the abdominal afferent nerves at least contribute to the reduction of food intake observed on second to fourth days after 6-Gy abdominal irradiation. Taken together, the present evidence suggests that the reduction of food intake following X-ray irradiation of the whole body or the abdomen is partly mediated via abdominal afferent nerves. Moreover, the results of X-ray irradiation to the head suggest that X-ray irradiation directly influences the central nervous system to reduce food intake.
恶性肿瘤的放射治疗常常引发厌食或食欲不振等不良反应。然而，其机制尚不清楚。本研究旨在调查内脏传入神经是否与X射线照射后食物摄入量减少有关。使用高能电子直线加速器，以4.9 Gy min(-1)的剂量率，将大鼠双侧暴露于总剂量为1.5、3和6 Gy的X射线（10 MV）照射下。全身、腹部或头部接受1.5、3和6 Gy的X射线照射后，食物摄入量呈剂量依赖性减少。全身或腹部X射线照射后食物摄入量的减少明显大于仅头部照射时。腹部接受6 Gy X射线照射后的前4天观察到食物摄入量减少，而在经辣椒素预处理使小直径传入神经被消融的动物中，同样6 Gy腹部照射后仅在第一天观察到食物摄入量减少。这些结果表明，腹部传入神经至少促成了6 Gy腹部照射后第二至四天观察到的食物摄入量减少。综上所述，目前的证据表明，全身或腹部X射线照射后食物摄入量的减少部分是通过腹部传入神经介导的。此外，头部X射线照射的结果表明，X射线照射直接影响中枢神经系统以减少食物摄入量。
