长期亚磁场处理降低成年雄性小鼠肌肉组织的线粒体功能和运动能力*

亚磁场是深空载人航天任务中的一个关键风险因素。研究表明，亚磁场影响动物多种运动相关行为，但长期亚磁场处理对成年个体运动能力的影响还需要进一步的研究，以评估深空飞行任务中亚磁场的潜在风险。本研究利用三轴亥姆霍兹线圈系统模拟的亚磁环境，长期（一个月）曝露处理成年雄性C57BL/6小鼠，并从行为，组织，细胞，分子水平研究其对小鼠运动能力的影响。相比于地磁组对照，亚磁组小鼠的耐力显著下降。并且，其骨骼肌中柠檬酸水平和肌膜下线粒体数量的下降，以及骨骼肌线粒体形态的变化，表明亚磁场诱导了肌肉线粒体功能抑制，并可能导致其与耐力密切相关的能量代谢的下降。我们的研究结果为线粒体直接响应亚磁场提供了体内证据，并且提示线粒体相关指标可能用于亚磁场效应的风险评估和干预药物的开发。

Long-term Hypogeomagnetic Field Exposure Reduces Muscular Mitochondrial Function and Exercise Capacity in Adult Male Mice *

The hypogeomagnetic field (HMF) is one of the key risk factors for manned deep space missions. It has been reported that HMF exposure affects multiple exercise-related behaviors of animals, but the long-term effects of HMF on the exercise capacity of adult humans needs further investigation to determine the potential risk of HMF exposure during deep space missions. In this study, we reared adult male C57BL/6 mice in an HMF for one month, simulated by a 3-axis Helmholtz coil system, and examined the effects on their exercise capacities at behavioral, tissue, cellular, and molecular levels. Compared with that of the control mice reared in the geomagnetic field, the endurance of the HMF-exposed mice was significantly reduced. Decreases were also observed in the citric acid level and the number of subsarcolemmal mitochondria in skeletal muscles, and morphological alterations of skeletal mitochondria were noted. These results indicate an HMF-induced inhibition of muscular mitochondrial function and an endurance-related decline in the process of energy metabolism. Our findings provide direct in vivo evidence to demonstrate that mitochondria can respond to HMF exposure and that mitochondrion-related indices could be used for risk evaluation and the development of methods of counteraction.