Metabolic, Nutrition, and Exercise Research (MiNER) Laboratory, Department of Kinesiology, The University of Texas at El Paso, 500 University Ave, El Paso, TX, 79968, USA.
The Cellular Characterization and Biorepository (CCB) Core Facility, Border Biomedical Research Center, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, USA.
Eur J Appl Physiol. 2023 Dec;123(12):2771-2778. doi: 10.1007/s00421-023-05266-5. Epub 2023 Jun 27.
Smaller lipid droplet morphology and GLUT 4 protein expression have been associated with greater muscle oxidative capacity and glucose uptake, respectively. The main purpose of this study was to determine the effect of an acute long-duration exercise bout on skeletal muscle lipid droplet morphology, GLUT4, perilipin 3, and perilipin 5 expressions.
Twenty healthy men (age 24.0 ± 1.0 years, BMI 23.6 ± 0.4 kg/m) were recruited for the study. The participants were subjected to an acute bout of exercise on a cycle ergometer at 50% VOmax until they reached a total energy expenditure of 650 kcal. The study was conducted after an overnight fast. Vastus lateralis muscle biopsies were obtained before and immediately after exercise for immunohistochemical analysis to determine lipid, perilipin 3, perilipin 5, and GLUT4 protein contents while GLUT 4 mRNA was quantified using RT-qPCR.
Lipid droplet size decreased whereas total intramyocellular lipid content tended to reduce (p = 0.07) after an acute bout of endurance exercise. The density of smaller lipid droplets in the peripheral sarcoplasmic region significantly increased (0.584 ± 0.04 to 0.638 ± 0.08 AU; p = 0.01) while larger lipid droplets significantly decreased (p < 0.05). GLUT4 mRNA tended to increase (p = 0.05). There were no significant changes in GLUT 4, perilipin 3, and perilipin 5 protein levels.
The study demonstrates that exercise may impact metabolism by enhancing the quantity of smaller lipid droplets over larger lipid droplets.
较小的脂滴形态和 GLUT4 蛋白表达分别与更大的肌肉氧化能力和葡萄糖摄取有关。本研究的主要目的是确定急性长时间运动对骨骼肌脂滴形态、GLUT4、 perilipin 3 和 perilipin 5 表达的影响。
招募了 20 名健康男性（年龄 24.0 ± 1.0 岁，BMI 23.6 ± 0.4 kg/m）参加研究。参与者在自行车测力计上进行急性运动，运动强度为 50%VOmax，直到总能量消耗达到 650kcal。研究在禁食一夜后进行。在运动前和运动后立即从股外侧肌获取活检标本，用于免疫组织化学分析，以确定脂质、 perilipin 3、 perilipin 5 和 GLUT4 蛋白含量，同时使用 RT-qPCR 定量 GLUT 4 mRNA。
急性耐力运动后，脂滴大小减小，而细胞内总脂质含量趋于减少（p=0.07）。外周肌浆区较小脂滴的密度显著增加（0.584±0.04 至 0.638±0.08 AU；p=0.01），而较大脂滴显著减少（p<0.05）。GLUT4 mRNA 有增加的趋势（p=0.05）。GLUT4、 perilipin 3 和 perilipin 5 蛋白水平没有显著变化。
该研究表明，运动可以通过增加较小脂滴的数量而不是较大脂滴来影响代谢。
