Miner J L, Cederberg C A, Nielsen M K, Chen X, Baile C A
Animal Science Department, University of Nebraska, Lincoln 68583-0908, USA.
Obes Res. 2001 Feb;9(2):129-34. doi: 10.1038/oby.2001.16.
The objective of the study was to determine if consumption of conjugated linoleic acid (CLA) by mice could induce apoptosis in adipose tissue. Other objectives were to determine the influence of feeding mice CLA for < or =2 weeks on body fat, energy expenditure, and feed intake.
A mixture of CLA isomers (predominantly c9,t11 and t10,c12) was included in the AIN-93G diet at 0, 1, and 2%, and fed to mice for 12 days (Trial 1), or was included at 2% and fed to mice for 0, 5, and 14 days (Trial 2). Feed intake was measured daily and energy expenditure was determined by direct calorimetry on day 9 in Trial 1. Retroperitoneal fat pads were analyzed for apoptosis by determination of DNA fragmentation.
Dietary CLA reduced feed intake by 10% to 12% (p < 0.01), but either did not influence or did not increase energy expenditure as indicated by heat loss. Body weight was not influenced by consumption of CLA in Trial 1 but was increased (p < 0.01) by CLA in Trial 2. Weights of retroperitoneal, epididymal, and brown adipose tissues were lower (p < 0.01) in animals fed CLA, although liver weight was increased (p < 0.10; Trial 1) or not changed (Trial 2). Analysis of retroperitoneal fat pad DNA from both trials indicated that apoptosis was increased (p < 0.01) by CLA consumption.
These results are interpreted to indicate that CLA consumption causes apoptosis in white adipose tissue. This effect occurs within 5 days of consuming a diet that contains CLA.
本研究的目的是确定小鼠食用共轭亚油酸（CLA）是否会诱导脂肪组织凋亡。其他目的是确定给小鼠喂食CLA≤2周对体脂、能量消耗和采食量的影响。
将CLA异构体混合物（主要为c9,t11和t10,c12）以0%、1%和2%的比例添加到AIN-93G日粮中，喂养小鼠12天（试验1），或以2%的比例添加并喂养小鼠0天、5天和14天（试验2）。每天测量采食量，并在试验1的第9天通过直接量热法测定能量消耗。通过测定DNA片段化分析腹膜后脂肪垫的凋亡情况。
日粮CLA使采食量降低了10%至12%（p<0.01），但如热量损失所示，对能量消耗要么没有影响，要么没有增加。试验1中，CLA的摄入对体重没有影响，但试验2中CLA使体重增加（p<0.01）。喂食CLA的动物腹膜后、附睾和棕色脂肪组织的重量较低（p<0.01），尽管肝脏重量增加（p<0.10；试验1）或没有变化（试验2）。对两个试验的腹膜后脂肪垫DNA分析表明，CLA的摄入会增加凋亡（p<0.01）。
这些结果被解释为表明CLA的摄入会导致白色脂肪组织凋亡。这种效应在食用含CLA日粮的5天内就会出现。
