Abstract：
Explorations of the Moon and Mars are planned as future manned space missions, during which humans will be exposed to both radiation and microgravity. We do not, however, know the health effects for such combined exposures. In a ground-based experiment, we evaluated the combined effects of radiation and simulated microgravity on tumorigenesis by performing X-irradiation and tail suspension in C3B6F1 ApcMin/+ mice, a well-established model for intestinal tumorigenesis. Mice were irradiated at 2 weeks of age and underwent tail suspension for 3 or 11 weeks using a special device that avoids damage to the tail. The tail suspension treatment significantly reduced the thymus weight after 3 weeks but not 11 weeks, suggesting a transient stress response. The combination of irradiation and tail suspension significantly increased the number of small intestinal tumors less than 2 mm in diameter as compared with either treatment alone. The combined treatment also increased the fraction of malignant tumors among all small intestinal tumors as compared with the radiation-only treatment. Thus, the C3B6F1 ApcMin/+ mouse is a useful model for assessing cancer risk in a simulated space environment, in which simulated microgravity accelerates tumor progression when combined with radiation exposure.
摘要：
探索月球和火星计划作为未来的载人航天任务，在此期间，人类将暴露在辐射和微重力下。我们没有,然而,了解这种联合暴露对健康的影响。在地面实验中，我们通过在C3B6F1ApcMin/+小鼠中进行X线照射和尾部悬吊来评估辐射和模拟微重力对肿瘤发生的联合影响，一个成熟的肠道肿瘤发生模型。在2周龄时照射小鼠,并使用避免对尾部造成损伤的特殊装置进行尾部悬吊3或11周。尾部悬吊治疗3周后显著降低胸腺重量，但11周后未显著降低胸腺重量，表明了短暂的应激反应。与单独的任一种治疗相比，辐射和尾部悬吊的组合显着增加了直径小于2mm的小肠肿瘤的数量。与仅放射治疗相比，联合治疗还增加了所有小肠肿瘤中恶性肿瘤的比例。因此，C3B6F1ApcMin/+小鼠是在模拟太空环境中评估癌症风险的有用模型，其中模拟微重力与辐射照射相结合会加速肿瘤进展。
