Nehrenberg Derrick L, Hua Kunjie, Estrada-Smith Daria, Garland Theodore, Pomp Daniel
Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina, USA.
Obesity (Silver Spring). 2009 Jul;17(7):1402-9. doi: 10.1038/oby.2009.51. Epub 2009 Mar 12.
Little is known about how genetic variation affects the capacity for exercise to change body composition. We examined the extent to which voluntary exercise alters body composition in several lines of selectively bred mice compared to controls. Lines studied included high runner (HR) (selected for high wheel running), M16 (selected for rapid weight gain), Institute of Cancer Research (ICR) (randomly bred as control for M16), M16i (an inbred line derived from M16), HE (selected for high percentage of body fat while holding body weight constant), LF (selected for low percentage of body fat), C57BL/6J (common inbred line), and the F1 between HR and C57BL/6J. Body weight and body fat were recorded before and after 6 days of free access to running wheels in males and females that were individually caged. Total food intake was measured during this 6-day period. All pre- and postexercise measures showed significant strain effects. While HR mice predictably exercised at higher levels, all other selection lines had decreased levels of wheel running relative to ICR. The HR x B6 F1 ran at similar levels to HR demonstrating complete dominance for voluntary exercise. Also, all strains lost body fat after exercise, but the relationships between exercise and changes in percent body were not uniform across genotypes. These results indicate that there is significant genetic variation for voluntary exercise and its effects on body composition. It is important to carefully consider genetic background and/or selection history when using mice to model effects of exercise on body composition, and perhaps, other complex traits as well.
关于基因变异如何影响运动改变身体成分的能力，目前所知甚少。我们研究了与对照组相比，选择性繁殖的几品系小鼠中自愿运动改变身体成分的程度。所研究的品系包括高跑步者（HR）（因高轮转跑步而选育）、M16（因体重快速增加而选育）、癌症研究所（ICR）（作为M16的随机繁殖对照）、M16i（源自M16的近交系）、HE（在保持体重恒定的同时因高脂肪百分比而选育）、LF（因低脂肪百分比而选育）、C57BL/6J（常见近交系）以及HR和C57BL/6J的F1代。将单独饲养的雄性和雌性小鼠在自由使用转轮6天前后记录体重和体脂。在此6天期间测量总食物摄入量。所有运动前和运动后的测量均显示出显著的品系效应。虽然HR小鼠如预期的那样运动量更高，但所有其他选择品系相对于ICR的轮转运动量均有所下降。HR×B6 F1代的运动量与HR相似，表明在自愿运动方面完全显性。此外，所有品系在运动后体脂均减少，但运动与体脂百分比变化之间的关系在不同基因型中并不一致。这些结果表明，自愿运动及其对身体成分的影响存在显著的基因变异。在使用小鼠模拟运动对身体成分的影响以及可能的其他复杂性状时，仔细考虑基因背景和/或选择历史非常重要。
