Schrauwen P, Hoppeler H, Billeter R, Bakker A H, Pendergast D R
Department of Human Biology, Maastricht University, Maastricht, The Netherlands.
Int J Obes Relat Metab Disord. 2001 Apr;25(4):449-56. doi: 10.1038/sj.ijo.0801566.
To test the hypothesis that consumption of a high-fat diet leads to an increase in UCP mRNA expression in human skeletal muscle. In a group of endurance athletes, with a range in fiber type distribution, we hypothesized that the effect of the high-fat diet on UCP2 and UCP3 mRNA expression is more pronounced in muscle fibers which are known to have a high capacity to shift from carbohydrate to fat oxidation (type IIA fibers).
Ten healthy trained athletes (five males, five females) consumed a low-fat diet (17+/-0.9 en% of fat) and high-fat diet (41.4+/-1.4 en% fat) for 4 weeks, separated by a 4 week wash-out period. Muscle biopsies were collected at the end of both dietary periods.
Using RT-PCR, levels of UCP2 and UCP3 mRNA expression were measured and the percentage of type I, IIA and IIB fibers were determined using the myofibrillar ATPase method in all subjects.
UCP3L mRNA expression tended to be higher on the high-fat diet, an effect which reached significance when only males were considered (P=0.037). Furthermore, diet-induced change in mRNA expression of UCP3T (r: 0.66, P=0.037), UCP3L (r: 0.61, P=0.06) and UCP2 (r: 0.70, P=0.025), but not UCP3S, correlated significantly with percentage dietary fat on the high-fat diet. Plasma FFA levels were not different during the two diets. Finally, the percentage of type IIA fibers was positively correlated with the diet-induced change in mRNA expression for UCP2 (r: 0.7, P=0.03), UCP3L (r: 0.73, P=0.016) and UCP3T (r: 0.68, P=0.03) but not with UCP3S (r: 0.06, NS).
UCP2 and UCP3 mRNAs are upregulated by a high-fat diet. This upregulation is more pronounced in humans with high proportions of type IIA fibers, suggesting a role for UCPs in lipid utilization.
验证高脂肪饮食会导致人类骨骼肌中解偶联蛋白（UCP）mRNA表达增加这一假说。在一组纤维类型分布各异的耐力运动员中，我们推测高脂肪饮食对UCP2和UCP3 mRNA表达的影响在已知具有从碳水化合物氧化向脂肪氧化转变高能力的肌纤维（IIA型纤维）中更为显著。
10名健康的训练有素的运动员（5名男性，5名女性）先食用低脂饮食（脂肪能量占比17±0.9%）4周，之后经过4周的洗脱期，再食用高脂肪饮食（脂肪能量占比41.4±1.4%）4周。在两个饮食阶段结束时采集肌肉活检样本。
使用逆转录聚合酶链反应（RT-PCR）测量UCP2和UCP3 mRNA表达水平，并使用肌原纤维ATP酶法测定所有受试者中I型、IIA型和IIB型纤维的百分比。
高脂肪饮食时UCP3L mRNA表达有升高趋势，仅考虑男性时这一效应具有统计学意义（P = 0.037）。此外，饮食诱导的UCP3T（r：0.66，P = 0.037）、UCP3L（r：0.61，P = 0.06）和UCP2（r：0.70，P = 0.025）mRNA表达变化，但不包括UCP3S，与高脂肪饮食中的膳食脂肪百分比显著相关。两种饮食期间血浆游离脂肪酸（FFA）水平无差异。最后，IIA型纤维的百分比与饮食诱导的UCP2（r：0.7，P = 0.03）、UCP3L（r：0.73，P = 0.016）和UCP3T（r：0.68，P = 0.03）mRNA表达变化呈正相关，但与UCP3S（r：0.06，无统计学意义）无关。
高脂肪饮食可上调UCP2和UCP3 mRNA表达。这种上调在IIA型纤维比例高的人群中更为明显，提示解偶联蛋白在脂质利用中发挥作用。
