Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN, USA.
Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, Medical School, University of Minnesota, Minneapolis, MN, USA.
Exp Physiol. 2020 Oct;105(10):1700-1707. doi: 10.1113/EP088827. Epub 2020 Sep 8.
What is the central question of this study? Oestradiol (E ) plays an important role in regulating skeletal muscle strength in females. To what extent does E deficiency affect recovery of strength and satellite cell number when muscle is challenged by multiple injuries? What is the main finding and its importance? E deficiency impairs the adaptive potential of skeletal muscle following repeated injuries, as measured by muscle mass and strength. The impairment is likely multifactorial with our data indicating that one mechanism is reduction in satellite cell number. Our findings have implications for ageing, hormone replacement and regenerative medicine in regards to maintaining satellite cell number and ultimately the preservation of skeletal muscle's adaptive potential.
Oestradiol's effects on skeletal muscle are multifactorial including the preservation of mass, contractility and regeneration. Here, we aimed to determine the extent to which oestradiol deficiency affects strength recovery when muscle is challenged by multiple BaCl -induced injuries and to assess how satellite cell number is influenced by the combination of oestradiol deficiency and repetitive skeletal muscle injuries. A longitudinal study was designed, using an in vivo anaesthetized mouse approach to precisely and repeatedly measure maximal isometric torque, coupled with endpoint fluorescence-activated cell sorting to quantify satellite cells. Isometric torque and strength gains were lower in ovariectomized mice at several time points after the injuries compared to those treated with 17β-oestradiol. Satellite cell number was 41-43% lower in placebo- than in oestradiol-treated ovariectomized mice, regardless of injury status or number of injuries. Together, these results indicate that the loss of oestradiol blunts adaptive strength gains and that the number of satellite cells likely contributes to the impairment.
本研究的核心问题是什么？雌激素（E）在调节女性骨骼肌力量方面起着重要作用。雌激素缺乏在多大程度上影响肌肉多次受伤后的力量恢复和卫星细胞数量？主要发现及其重要性是什么？E 缺乏会损害多次受伤后骨骼肌的适应潜力，这可通过肌肉质量和力量来衡量。这种损害可能是多因素的，我们的数据表明，其中一个机制是卫星细胞数量减少。我们的研究结果对于衰老、激素替代和再生医学具有重要意义，因为它们涉及维持卫星细胞数量，最终维持骨骼肌的适应潜力。
雌激素对骨骼肌的作用是多方面的，包括维持质量、收缩性和再生。在这里，我们旨在确定雌激素缺乏在多大程度上影响肌肉多次 BaCl 诱导损伤后的力量恢复，并评估雌激素缺乏和重复骨骼肌损伤结合对卫星细胞数量的影响。采用体内麻醉小鼠方法进行了一项纵向研究，以精确和重复测量最大等长扭矩，并结合终点荧光激活细胞分选来定量卫星细胞。与用 17β-雌二醇治疗的小鼠相比，卵巢切除小鼠在受伤后的几个时间点的等长扭矩和力量增加较低。无论损伤状态或损伤次数如何，安慰剂治疗的卵巢切除小鼠中的卫星细胞数量比用雌二醇治疗的卵巢切除小鼠低 41-43%。这些结果表明，雌激素的丧失会削弱适应性力量增加，并且卫星细胞的数量可能导致这种损害。
