Antonio J, Gonyea W J
University of Texas Southwestern Medical Center, Department of Cell Biology and Neuroscience, Dallas 75235-9039.
Med Sci Sports Exerc. 1994 Aug;26(8):973-7.
This study examined the role of longitudinal fiber splitting in enlarged anterior latissimus dorsi (ALD) muscle of adult quail. Muscle hypertrophy was induced using a model of progressive stretch overload (PSO) (5). After 16 and 28 d of PSO, muscle mass in the stretched ALD muscle increased significantly (P < 0.05) 188% and 294%, respectively, when compared with the intra-animal control muscle. Muscle length increased significantly (P < 0.05) in the stretched ALD muscle vs the intra-animal control by approximately 77% for both groups. Fiber number, which was assessed using direct counts after nitric acid digestion, did not change in the 16-d group; however, the 28-d stretched ALD muscle exhibited a 30% increase (P < 0.05) in fiber number vs the intra-animal control muscle. Furthermore, the frequency of splitting (i.e., branching) fibers was less than 0.3% in all muscles examined except the 28-d stretched ALD muscle. The 28-d stretched ALD muscle had 5.25% of its muscle fibers exhibiting split profiles. These results demonstrate that PSO produces effects unlike chronic stretch overload in that longitudinal fiber splitting may contribute significantly to an increase in fiber number.
本研究探讨了纵向纤维分裂在成年鹌鹑扩大的背阔肌（ALD）中的作用。采用渐进性拉伸过载（PSO）模型诱导肌肉肥大（5）。在PSO处理16天和28天后，与动物体内对照肌肉相比，拉伸的ALD肌肉质量显著增加（P < 0.05），分别增加了188%和294%。拉伸的ALD肌肉长度与动物体内对照相比显著增加（P < 0.05），两组均增加了约77%。使用硝酸消化后直接计数评估的纤维数量在16天组中没有变化；然而，与动物体内对照肌肉相比，28天拉伸的ALD肌肉纤维数量增加了30%（P < 0.05）。此外，除28天拉伸的ALD肌肉外，所有检查的肌肉中分裂（即分支）纤维的频率均低于0.3%。28天拉伸的ALD肌肉中有5.25%的肌纤维呈现分裂形态。这些结果表明，PSO产生的效果与慢性拉伸过载不同，纵向纤维分裂可能对纤维数量的增加有显著贡献。
