He Jing, Goodpaster Bret H, Kelley David E
Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh School of Medicine, Pennsyvania, USA.
Obes Res. 2004 May;12(5):761-9. doi: 10.1038/oby.2004.92.
To address the potential effects of weight loss and physical activity (WL + Ex) on intramyocellular lipid (IMCL) and lipid droplet size in overweight and obese previously sedentary individuals.
IMCL and lipid droplet size was determined in vastus lateralis, obtained by percutaneous biopsy, from 21 obese volunteers (9 men/12 women), using Oil Red O staining, along with succinate dehydrogenase histochemistry and mitochondrial immunohistochemistry as measures of skeletal muscle oxidative capacity. Insulin sensitivity (IS) was determined by glucose clamp.
A 4-month WL + Ex intervention resulted in approximately 10% WL and approximately 15% increase in maximal oxygen uptake, leading to a 46% increase in IS (all p < 0.01). IMCL did not significantly change (p = 0.36). However, the size of lipid droplets decreased after WL + Ex (p < 0.01), and this decrease in lipid droplet size correlated with increased IS (p < 0.01) and the amount of physical activity (p < 0.05). Succinate dehydrogenase activity and mitochondrial labeling increased significantly (p < 0.01), without a significant shift in fiber type distribution.
In summary, IMCL does not decrease in response to WL + Ex in obese, previously sedentary individuals, yet the lipid within muscle is dispersed into smaller droplets. This change in the size of lipid droplets, likely coupled with a concomitant increase in oxidative enzyme capacity, is correlated to improved IS.
探讨体重减轻和体育活动（WL + Ex）对超重和肥胖的久坐不动个体肌内脂质（IMCL）和脂滴大小的潜在影响。
通过经皮活检从21名肥胖志愿者（9名男性/12名女性）的股外侧肌中获取样本，采用油红O染色法测定IMCL和脂滴大小，同时采用琥珀酸脱氢酶组织化学和线粒体免疫组织化学方法作为骨骼肌氧化能力的指标。通过葡萄糖钳夹法测定胰岛素敏感性（IS）。
为期4个月的WL + Ex干预导致体重减轻约10%，最大摄氧量增加约15%，IS增加46%（所有p < 0.01）。IMCL无显著变化（p = 0.36）。然而，WL + Ex后脂滴大小减小（p < 0.01），脂滴大小的减小与IS增加（p < 0.01）和体育活动量增加（p < 0.05）相关。琥珀酸脱氢酶活性和线粒体标记显著增加（p < 0.01），纤维类型分布无显著变化。
总之，在肥胖的久坐不动个体中，IMCL不会因WL + Ex而减少，但肌肉内的脂质会分散成更小的脂滴。脂滴大小的这种变化可能与氧化酶能力的同时增加有关，与IS改善相关。
