高脂和限食对不同肥胖易感性大鼠能量代谢的影响

Effect of high-fat diet and food restriction on energy metabolism in obesity-prone and obesity-resistant rats

目的探讨不同肥胖易感性大鼠在高脂饲料及半量限食状态下能量代谢的差异。方法健康雄性SD大鼠60只,高脂饲料喂养3周,按体重增加量排序筛选出肥胖易感(obesity-prone,OP)、肥胖抵抗(obesity-resistant,OR)和对照组,继续喂养12周;由各组随机挑选一半动物进行半量限食饲喂,另一半继续自由采食,持续2周。间接测热法测量大鼠基础代谢率(BMR)、静息代谢率(RMR)等代谢指标;处死动物,分离肾周、睾周和大网膜脂肪,计算体脂百分比。结果在高脂饲料状态下,OR大鼠BMR、RMR显著高于OP组和对照组;在半量限食状态下,OR大鼠BMR、RMR显著低于OP组和对照组。在限食状态下OP、OR及对照组大鼠BMR、RMR较自由采食状态均有所降低,OR组降幅最大;经过2周限食后,OP组体脂百分比下降显著,而OR组基本无变化。结论 OP、OR大鼠在高脂饲料或半量限食状态下代谢水平均存在显著差异,OR较OP对能量摄入水平的变化反应更为灵敏。

Objective To explore the effect of high-fat diet and food restriction on energy metabolism in obesity-prone（ OP） and obesity-resistant（ OR） rats. Methods Sixty male Sprague-Dawley（ SD） rats were divided into OP,OR and control groups according to their body weight gain after fed with high-fat diet for 3 wk. OP and OR groups were fed with high-fat diet in the following 12 wk to promote the development of obesity. Then one-half of the rats of each group began to food restriction and were allowed access to 50% of their individual baseline mean daily food intake each day,while the other half were maintained on ad libitum food for 2 wk. Basal metabolic rate（ BMR）,resting metabolic rate（ RMR） of each group were measured by indirect calorimetry during the high-fat diet feeding and food restriction conditions. After the rats were sacrificed,body fat content was measured. Results OR rats had significantly higher BMR and RMR than the other two groups during high-fat diet feeding condition. There was no significant difference between OP and control group. Food restriction led to a reduction in BMR andRMR in all groups. OR rats showed a significantly greater reduction. OP group showed a significant decrease in body fat weight and fat content during the food restriction period,while there was no significant differences in OR rats. Conclusion There are significant differences between OP and OR rats in BMR and RMR either in high-fat diet feeding condition or food restricted state. OR rat has the ability to sense and respond to energy imbalance more accurately than OP rat.