生物谷Bioon.com 讯 一项研究发现，锻炼引起的肌纤维核的并入可能有助于肌纤维在不使用肌肉一段时间导致萎缩之后恢复尺寸。
热衷于锻炼的人知道肌肉力量训练会导致肌肉尺寸的增加，而当训练停止之后又会消失；肌纤维萎缩是由于不活动。但是此前进行过的锻炼能够帮助萎缩的肌纤维在重新锻炼之后较快地重新恢复尺寸的机制仍然不清楚。Kristian Gundersen及其同事对啮齿动物的肌肉进行了成像实验，从而找到这类“肌肉记忆”的细胞基质。
这组作者发现，在经过了一段类似于力量训练的过量锻炼之后，新的核在肌纤维尺寸生长之前加入到了肌纤维中。这组作者报告说，在超负荷训练停止之后，肌纤维还在相当长的时间里保持了这些核。此外，这些核帮助延迟了肌肉萎缩。这组作者提出，由于产生新核的能力随着年龄增长而逐渐减少，人们可能会从年轻的时候进行力量锻炼中受益。
生物谷推荐原文出处：
PNAS doi: 10.1073/pnas.0913935107
Myonuclei acquired by overload exercise precede hypertrophy and are not lost upon detraining
J. C. Bruusgaard, I. B. Johansen, I. M. Egner, Z. A. Rana, and K. Gundersen 1
Department of Molecular Biosciences, University of Oslo, 0371 Oslo, Norway
Effects of previous strength training can be long-lived, even after prolonged subsequent inactivity, and retraining is facilitated by a previous training episode. Traditionally, such “muscle memory” has been attributed to neural factors in the absence of any identified local memory mechanism in the muscle tissue. We have used in vivo imaging techniques to study live myonuclei belonging to distinct muscle fibers and observe that new myonuclei are added before any major increase in size during overload. The old and newly acquired nuclei are retained during severe atrophy caused by subsequent denervation lasting for a considerable period of the animal's lifespan. The myonuclei seem to be protected from the high apoptotic activity found in inactive muscle tissue. A hypertrophy episode leading to a lasting elevated number of myonuclei retarded disuse atrophy, and the nuclei could serve as a cell biological substrate for such memory. Because the ability to create myonuclei is impaired in the elderly, individuals may benefit from strength training at an early age, and because anabolic steroids facilitate more myonuclei, nuclear permanency may also have implications for exclusion periods after a doping offense.
