MUSCLE-FIBER FORMATION AND FIBER HYPERTROPHY DURING THE ONSET OF STRETCH-OVERLOAD
MUSCLE-FIBER FORMATION AND FIBER HYPERTROPHY DURING THE ONSET OF STRETCH-OVERLOAD
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DOI：
10.1152/ajpcell.1990.259.1.c92
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发表时间：
1990-07-01
影响因子：
--
通讯作者：
DAVIS, ME
中科院分区：
文献类型：
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作者：
ALWAY, SE;GONYEA, WJ;DAVIS, ME
在成年日本鹌鹑的背阔肌（ALD）中评价了纤维肥大和新纤维形成对牵张诱导的肌肉增大的作用，因为尚不清楚启动新纤维形成的机制是否依赖于首先实现显著的纤维肥大。相当于鸟体重10%的重量被固定在一只翅膀上，在拉伸的第一周，每天杀死8只鸟。肌肉质量显着增加后48小时的拉伸，然而，在非肌肉组织的海拔占这种增加。在拉伸的第四天，非肌肉组织校正的肌肉质量显著大于动物内对照。平均纤维横截面积在第0-6天没有变化，但横截面积为30.0 ± 0.00000。第7天，比动物内对照面积大17.2%。硝酸消化结缔组织后测得的纤维数为27.1 ± 0.01。在拉伸的第5-7天比动物内对照高5.8%，但在第5和6天对照肌肉中的纤维数量低于第0天。因此，新的纤维形成之前没有显着的纤维肥大。这些结果未能支持新纤维形成的机制，该机制涉及在拉伸的第一周期间从肥大的肌纤维分裂的纤维。
The contributions of fiber hypertrophy and new fiber formation to the onset of stretch-induced muscle enlargement were evaluated in the anterior latissimus dorsi (ALD) of adult Japanese quails, because it was not known whether the mechanisms which initiate new fiber formation were dependent on first achieving significant fiber hypertrophy. A weight corresponding to 10% of the bird''s body mass was attached to one wing, and eight birds were killed after each day during the first week of stretch. Muscle mass was significantly increased after 48 h of stretch; however, the elevation in nonmuscle tissue accounted for this increase. Muscle mass corrected for nonmuscle tissue was significantly greater than the intra-animal control by the fourth day of stretch. Mean fiber cross-sectional area did not change during days 0-6, but cross-sectional area was 30.0 .+-. 17.2% greater than the intra-animal control areas at day 7. Fiber number determined after nitric acid digestion of connective tissue was 27.1 .+-. 5.8% greater than the intra-animal control at days 5-7 of stretch, but the number of fibers in the control muscles at days 5 and 6 were lower than at day 0. Thus new fiber formation was not preceded by significant fiber hypertrophy. These results fail to support a mechanism for new fiber formation which involves fiber splitting from hypertrophied myofibers during the first week of stretch.