Whittom F, Jobin J, Simard P M, Leblanc P, Simard C, Bernard S, Belleau R, Maltais F
Unité de recherche, Institut de Cardiologie et de Pneumologie de Québec, Canada.
Med Sci Sports Exerc. 1998 Oct;30(10):1467-74. doi: 10.1097/00005768-199810000-00001.
In this study, we examined the fiber-type proportions, cross-sectional areas (CSA), and capillarization from needle biopsies of the vastus lateralis muscle in 20 patients with chronic obstructive pulmonary disease (COPD) (FEV1 = 37 +/- 11% predicted, peak VO2 = 13 +/- 4 mL.min-1.kg-1) and nine age-matched normal subjects (peak VO2 = 33 +/- 7 mL.min-1.kg-1). The effects of endurance training on these parameters were also evaluated in 11 of the 20 patients with COPD.
The proportion of Type I fiber was smaller in COPD than normals (34 +/- 14% vs 58 +/- 16 in normals, P < 0.0005) with a corresponding increase in Type IIb fiber (P = 0.015). The CSA of Type I, IIa, and IIab fibers was also smaller in COPD. The capillary to fiber ratio tended to be reduced in patients, but this difference did not reach statistical significance (P = 0.15). The number of capillary contact for Type I, IIa, and IIab fibers was significantly reduced in COPD compared with normal subjects (P < 0.05). When corrected for the CSA, this parameter was similar for both groups. After training, peak VO2 increased by 11% (P < 0.05), the fiber-type proportion remained unchanged, and the CSA of Type I and IIa fibers increased by 31 and 21%, respectively (P < 0.05). Although the number of capillary contact for each fiber types increased with training, the capillary to fiber ratio and the number of capillary contact for the different fiber types relative to their CSA remain unchanged.
We conclude that in COPD, 1) the vastus lateralis muscle is characterized by a marked decrease in Type I fiber proportion, an increase in Type IIb fiber proportion, a decrease in Type I, IIa, and IIab fiber CSA and by a relatively preserved capillarization; and 2) a 12-wk training program induces a significant increase in Type I and IIa CSA.
在本研究中，我们检测了20例慢性阻塞性肺疾病（COPD）患者（预测第一秒用力呼气容积[FEV1]=37±11%，峰值摄氧量[peak VO2]=13±4 mL·min-1·kg-1）和9名年龄匹配的正常受试者（peak VO2=33±7 mL·min-1·kg-1）股外侧肌针吸活检标本中的纤维类型比例、横截面积（CSA）和毛细血管密度。我们还评估了20例COPD患者中11例患者进行耐力训练对这些参数的影响。
COPD患者的I型纤维比例低于正常受试者（分别为34±14%和58±16%，P<0.0005），相应地IIb型纤维比例增加（P=0.015）。COPD患者的I型、IIa型和IIab型纤维CSA也较小。患者的毛细血管与纤维比例有降低趋势，但差异无统计学意义（P=0.15）。与正常受试者相比，COPD患者I型、IIa型和IIab型纤维的毛细血管接触数量显著减少（P<0.05）。校正CSA后，两组该参数相似。训练后，peak VO2增加11%（P<0.05），纤维类型比例保持不变，I型和IIa型纤维CSA分别增加31%和21%（P<0.05）。尽管每种纤维类型的毛细血管接触数量随训练增加，但毛细血管与纤维比例以及不同纤维类型相对于其CSA的毛细血管接触数量保持不变。
我们得出结论，在COPD患者中，1）股外侧肌的特征为I型纤维比例显著降低、IIb型纤维比例增加、I型、IIa型和IIab型纤维CSA减小以及毛细血管密度相对保留；2）为期12周的训练计划可使I型和IIa型纤维CSA显著增加。
