Sadowska Julita, Gębczyński Andrzej K, Konarzewski Marek
Institute of Biology, University of Białystok, Białystok, Poland.
PLoS One. 2017 Feb 24;12(2):e0172892. doi: 10.1371/journal.pone.0172892. eCollection 2017.
Factors affecting contribution of spontaneous physical activity (SPA; activity associated with everyday tasks) to energy balance of humans are not well understood, as it is not clear whether low activity is related to dietary habits, precedes obesity or is a result of thereof. In particular, human studies on SPA and basal metabolic rates (BMR, accounting for >50% of human energy budget) and their associations with diet composition, metabolic thrift and obesity are equivocal. To clarify these ambiguities we used a unique animal model-mice selected for divergent BMR rates (the H-BMR and L-BMR line type) presenting a 50% between-line type difference in the primary selected trait. Males of each line type were divided into three groups and fed either a high fat, high carb or a control diet. They then spent 4 months in individual cages under conditions emulating human "sedentary lifestyle", with SPA followed every month and measurements of metabolic risk indicators (body fat mass %, blood lipid profile, fasting blood glucose levels and oxidative damage in the livers, kidneys and hearts) taken at the end of study. Mice with genetically determined high BMR assimilated more energy and had higher SPA irrespective of type of diet. H-BMR individuals were characterized by lower dry body fat mass %, better lipid profile and lower fasting blood glucose levels, but higher oxidative damage in the livers and hearts. Genetically determined high BMR may be a protective factor against diet-induced obesity and most of the metabolic syndrome indicators. Elevated spontaneous activity is correlated with high BMR, and constitutes an important factor affecting individual capability to sustain energy balance even under energy dense diets.
影响自发身体活动（SPA；与日常任务相关的活动）对人体能量平衡贡献的因素尚未得到充分理解，因为尚不清楚低活动量是与饮食习惯有关、先于肥胖出现还是肥胖的结果。特别是，关于SPA与基础代谢率（BMR，占人体能量预算的50%以上）及其与饮食组成、代谢节俭和肥胖之间关联的人体研究结果并不明确。为了澄清这些模糊之处，我们使用了一种独特的动物模型——选择具有不同BMR率的小鼠（高BMR和低BMR品系），其主要选择性状在品系间存在50%的差异。每个品系的雄性小鼠被分为三组，分别喂食高脂肪、高碳水化合物或对照饮食。然后，它们在模拟人类“久坐生活方式”的条件下在单独的笼子里饲养4个月，每月跟踪测量SPA，并在研究结束时测量代谢风险指标（体脂质量百分比、血脂谱、空腹血糖水平以及肝脏、肾脏和心脏的氧化损伤）。无论饮食类型如何，基因决定的高BMR小鼠吸收更多能量且具有更高的SPA。高BMR个体的特征是较低的干体脂质量百分比、更好的血脂谱和较低的空腹血糖水平，但肝脏和心脏的氧化损伤较高。基因决定的高BMR可能是预防饮食诱导肥胖和大多数代谢综合征指标的保护因素。自发活动增加与高BMR相关，并且即使在能量密集型饮食下，也是影响个体维持能量平衡能力的重要因素。
