Carson J A, Yamaguchi M, Alway S E
Department of Exercise Science, Ohio State University, Columbus 43210.
J Appl Physiol (1985). 1995 Jan;78(1):293-9. doi: 10.1152/jappl.1995.78.1.293.
The purpose of this study was to determined whether fibers in the anterior latissimus dorsi (ALD) muscle from aged Japanese quail have decreased hypertrophic or proliferative responses to 30 days of stretch overload compared with fibers from adult birds. Two groups of quail were studied, 12-wk-old quail (adult; n = 16) and 90-wk-old quail (aged; n = 16). The left wing of each bird was overloaded with a weight corresponding to 10% of the bird's body weight, and the right wing served as the intra-animal control. Quails were killed after 30 days of stretch overload. Total fiber number was quantified by counting all the fibers in a transverse section from the midbelly of the ALD muscle. ALD muscles in aged quails retained the capacity to increase their muscle mass (145%), total fiber number (49%), and fiber cross-sectional area (54%) in response to stretch overload. The ALD muscle in aged quail had a significantly lower increase in muscle mass (33%) and mass corrected for nonmuscle tissue (36%) compared with the ALD from young adult birds. Age had no effect on fiber type distribution shifts with stretch. These results suggest that although muscles in old birds have a substantial ability to adapt to enlarge, stretch-induced hypertrophy is attenuated in muscles from old quail.
本研究的目的是确定与成年鹌鹑相比，老年日本鹌鹑背阔肌前部（ALD）的纤维在30天的拉伸超负荷下是否具有降低的肥大或增殖反应。研究了两组鹌鹑，12周龄的鹌鹑（成年；n = 16）和90周龄的鹌鹑（老年；n = 16）。每只鸟的左翼加载相当于其体重10%的重量，右翼作为动物体内对照。在拉伸超负荷30天后处死鹌鹑。通过计数ALD肌腹中横切面上的所有纤维来量化总纤维数。老年鹌鹑的ALD肌保留了响应拉伸超负荷增加其肌肉质量（145%）、总纤维数（49%）和纤维横截面积（54%）的能力。与年轻成年鹌鹑的ALD相比，老年鹌鹑的ALD肌在肌肉质量（33%）和非肌肉组织校正后的质量（36%）方面的增加显著更低。年龄对拉伸引起的纤维类型分布变化没有影响。这些结果表明，虽然老年鸟类的肌肉具有显著的适应增大的能力，但老年鹌鹑肌肉中的拉伸诱导肥大减弱。
