IOS: Acclimation to Hypoxia in Deer Mice

IOS：鹿鼠缺氧的适应

• 批准号: 1457000
• 负责人: Kimberly Hammond
• 金额: $ 40.37万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457000&HistoricalAwards=false
• 关键词: IOS; Acclimation; Hypoxia; Deer; Mice

Deer mice inhabit the broadest altitudinal distribution of any North American mammal, from below sea level (Death Valley) to above 4000 m where hypoxic conditions are the norm and the deer mice must adapt their physiology to satisfy oxygen demand. It appears from recent research that previously described hemoglobin/genetic adaptations exert very modest effects on oxygen acquisition and are insufficient alone to explain the success and activity levels of deer mice at high altitude. Deer mice also display changes in organ sizes (e.g., heart, lung) that vary along the altitude gradient and are correlated with improved aerobic performance necessary for high levels of activity. This project will investigate the extent to which changes in lung size and function contribute to the observed increases in activity in adult mice acclimated to high altitude. Students will participate in all data collection aspects of the proposed research and contribute to the development of educational modules for undergraduate classes and outreach efforts to the public and citizen science workshops in the Southern California region. Results from the study will be further disseminated through publication in peer-reviewed journals and presentations at scientific meetings.Preliminary data from the principle investigator's lab suggests that the capacity of the lung to deliver oxygen at high altitude is the first critical limit in the oxygen cascade and that, in deer mice, the lung has the capacity to remodel to meet that demand. Such pulmonary plasticity would be highly adaptive if species are moving upward in elevation as the climate becomes warmer. This project will therefore test the hypothesis that some animals have the capacity to remodel lung architecture and optimize function throughout their lives. Changes in the cardio-pulmonary tissues between the high- and low-altitude acclimated mice will be assessed through histologic and physiologic assays. Modified gas composition will be used in direct respirometry tests of lung performance in control (normoxic) and altitude-acclimated animals. Lung volume, alveolar surface area, capillary density and blood gas composition will be tested to determine the extent to which organ size, architecture, and composition changes contribute to high altitude acclimation. Results from this study will inform our understanding of how small mammal populations that are forced to move to higher altitudes and harsh or variable conditions as a result of climate change will cope with their relocation.

鹿鼠生活在北美所有哺乳动物中海拔分布最广的地区，从海平面以下（死亡谷）到海拔4000米以上，那里缺氧是常态，鹿鼠必须适应自己的生理机能以满足氧气需求。从最近的研究来看，先前描述的血红蛋白/基因适应对氧气获取的影响非常有限，不足以单独解释鹿鼠在高海拔地区的成功和活动水平。鹿鼠的器官大小（如心脏、肺）也会随着海拔梯度的变化而变化，这与高水平运动所需的有氧运动能力的提高有关。该项目将调查在多大程度上肺大小和功能的变化有助于观察到的活动增加在成年小鼠适应高海拔。学生将参与拟议研究的所有数据收集方面，并为本科课程的教育模块的开发和南加州地区公众和公民科学研讨会的推广工作做出贡献。这项研究的结果将通过在同行评议的期刊上发表和在科学会议上发言进一步传播。来自首席研究员实验室的初步数据表明，在高海拔地区，肺输送氧气的能力是氧气级联的第一个关键极限，而在鹿鼠身上，肺有能力改造以满足这种需求。如果随着气候变暖，物种向上迁移，这种肺可塑性将具有高度适应性。因此，该项目将验证一些动物在其一生中具有重塑肺结构和优化功能的能力的假设。我们将通过组织学和生理学检查来评估高海拔和低海拔小鼠心肺组织的变化。改良的气体成分将用于对照（常氧）和高原适应动物肺功能的直接呼吸测定试验。肺容量、肺泡表面积、毛细血管密度和血气成分将被检测，以确定器官大小、结构和成分变化对高原适应的影响程度。这项研究的结果将告诉我们，由于气候变化，小型哺乳动物种群被迫迁移到更高的海拔和恶劣或多变的条件下，它们将如何应对搬迁。