Trappe Todd A, Ratchford Stephen M, Brower Brooke E, Liu Sophia Z, Lavin Kaleen M, Carroll Chad C, Jemiolo Bozena, Trappe Scott W
Human Performance Laboratory, Ball State University, Muncie, Indiana.
J Gerontol A Biol Sci Med Sci. 2016 Oct;71(10):1289-94. doi: 10.1093/gerona/glv231. Epub 2016 Jan 26.
Common cyclooxygenase (COX)-inhibiting drugs enhance resistance exercise induced muscle mass and strength gains in older individuals. The purpose of this investigation was to determine whether the underlying mechanism regulating this effect was specific to Type I or Type II muscle fibers, which have different contractile and metabolic profiles. Muscle biopsies (vastus lateralis) were obtained before and after 12 weeks of knee-extensor resistance exercise (3 days/week) from healthy older men who consumed either a placebo (n = 8; 64±2 years) or COX inhibitor (acetaminophen, 4 gram/day; n = 7; 64±1 years) in double-blind fashion. Muscle samples were examined for Type I and II fiber cross-sectional area, capillarization, and metabolic enzyme activities (glycogen phosphorylase, citrate synthase, β-hydroxyacyl-CoA-dehydrogenase). Type I fiber size did not change with training in the placebo group (304±590 μm(2)) but increased 28% in the COX inhibitor group (1,388±760 μm(2), p < .1). Type II fiber size increased 26% in the placebo group (1,432±499 μm(2), p < .05) and 37% in the COX inhibitor group (1,825±400 μm(2), p < .05). Muscle capillarization and enzyme activity were generally maintained in the placebo group. However, capillary to fiber ratio increased 24% (p < .1) and citrate synthase activity increased 18% (p < .05) in the COX inhibitor group. COX inhibitor consumption during resistance exercise in older individuals enhances myocellular growth, and this effect is more pronounced in Type I muscle fibers.
常见的环氧化酶（COX）抑制药物可增强老年人抗阻运动诱导的肌肉质量和力量增长。本研究的目的是确定调节这种效应的潜在机制是否特定于具有不同收缩和代谢特征的I型或II型肌纤维。在12周的伸膝抗阻运动（每周3天）前后，从健康老年男性中获取外侧股四头肌肌肉活检样本，这些男性以双盲方式服用安慰剂（n = 8；64±2岁）或COX抑制剂（对乙酰氨基酚，4克/天；n = 7；64±1岁）。检查肌肉样本的I型和II型纤维横截面积、毛细血管化程度和代谢酶活性（糖原磷酸化酶、柠檬酸合酶、β-羟酰基辅酶A脱氢酶）。在安慰剂组中，I型纤维大小在训练后没有变化（304±590μm²），但在COX抑制剂组中增加了28%（1388±760μm²，p < 0.1）。在安慰剂组中，II型纤维大小增加了26%（1432±499μm²，p < 0.05），在COX抑制剂组中增加了37%（1825±400μm²，p < 0.05）。安慰剂组的肌肉毛细血管化程度和酶活性总体保持不变。然而，在COX抑制剂组中，毛细血管与纤维的比例增加了24%（p < 0.1），柠檬酸合酶活性增加了18%（p < 0.05）。在老年人抗阻运动期间服用COX抑制剂可促进肌细胞生长，且这种效应在I型肌纤维中更为明显。
