Medium chain fatty acid regulates uncoupling protein 3 expression in skeletal muscle

长链脂肪酸被纳入乳糜微粒并通过淋巴运输，而中链脂肪酸则在门静脉血液中直接运输到肝脏并立即作为能量消耗掉。然而，中链脂肪酸在骨骼肌能量消耗中的作用尚不清楚。在本研究中，我们发现解偶联蛋白3（UCP3）和丙酮酸脱氢酶激酶4（PDK4）在中链脂肪酸处理的肌肉细胞中表达增加。与模拟转染的细胞相比，转染fatp1的细胞对中链脂肪酸的摄取明显增加。此外，选择性PPAR-δ拮抗剂GSK0660可阻断中链脂肪酸诱导的UCP3在肌肉细胞中的表达。这些发现表明，中链脂肪酸保护肥胖的机制可能涉及骨骼肌中UCP3的表达，从而增加体温调节。

Long chain fatty acids are incorporated into chylomicrons and transported trough lymph, whereas medium chain fatty acids which are transported in the portal blood directly to the liver and are consumed as energy immediately. However, the role of medium chain fatty acids on energy expenditure in skeletal muscle was unclear. In the present study, we found that the expression of uncoupling protein 3(UCP3) and pyruvate dehydrogenase kinase 4(PDK4) was increased in medium chain fatty acid-treated muscle cells. The uptake of medium chain fatty acids in FATP1-transfected cells significantly increased, compared with that in mock-transfected cells. Furthermore, the expression of UCP3 induced by medium chain fatty acid was blocked with GSK0660, a selective PPAR-δantagonist, in muscle cells. These findings suggest that medium chain fatty acids protect the obesity by a mechanism that may involve in the expression of UCP3 in skeletal muscle, resulting in increased thermoregulation.