Bioenergetic Mechanisms of Tongue Muscle Fatigue

疲劳是肌肉老化的一个特征，它是由多种因素引起的，包括生物能量变化 促进肌肉新陈代谢的物质。舌肌的生物能量特性的改变可能是 与年龄相关的吞咽障碍。然而，舌肌生物能量学与肌肉的关系 疲劳和行为治疗(如运动)的优化方式都很差 明白了。如果被阐明，这一知识将有助于提高治疗效果。由于我们不断增加的 65岁以上的人口，到2100年美国将超过1.31亿人，有效 对与年龄相关的吞咽障碍的干预至关重要。我们的全球假设是，与年龄相关的增长 在舌部，肌肉疲劳是导致吞咽功能随年龄增长而下降的主要原因。我们进一步 假设舌头运动可以缓解这些与疲劳和年龄相关的缺陷。我们将深入了解 通过在大鼠模型中解决我们每个目标的特定假说来研究舌肌疲劳的机制。 我们将使用神经肌肉电技术制造轻度和中度的舌肌疲劳 运动前的刺激：1)肌肉收缩功能和毛细血管血流量的生理学分析； 2)肌肉生物能量学的生物测定；3)吞咽的行为和生物力学测量 年轻的成年和老年的大鼠，接受了舌头(或假对照)运动。我们的舌头练习计划 是仿照目前临床实践中使用的那些。我们有三个具体目标：目标1将检验假设 舌肌疲劳随着年龄的增长而增加，随着年龄的增长，疲劳会加剧，而且 通过舌头练习拯救；目标2将量化外在和内在舌头的生物能量机制 肌肉来测试与疲劳相关的生物变量随着年龄和年龄的增长而降低的假设 通过舌头练习使之正常化；目标3将检验吞咽结果为负面的假设 受衰老和疲劳的影响，并通过舌头运动得到缓解。我们的神经肌肉模型是第一个 评估生物能量途径与年龄和舌肌运动的适应性。建议数 研究将为年龄相关性舌肌疲劳的机制提供新的理解 从生理学的角度来看，结构变化与生理功能的关系，以及 语言锻炼作为肌肉疲劳干预的有效性。这项工作非常有意义，因为 将受益于临床前优化治疗的大量且不断增长的老龄人口 针对经常使人衰弱的吞咽障碍的研究。

Fatigue is a characteristic of aging muscles that results from multiple factors including bioenergetic changes that contribute to muscle metabolism. Alterations in bioenergetic properties of tongue muscles likely contribute to age-related swallowing impairments. However, the relationship of tongue muscle bioenergetics to muscle fatigue and the manner in which behavioral treatments, such as exercise, may be optimized are poorly understood. If elucidated, this knowledge will allow improvement of treatment efficacy. Due to our increasing population of people over the age of 65, which will number over 131 million in the US by 2100, efficacious interventions for age-related deglutition deficits are critical. Our global hypothesis is that age-related increases in tongue muscle fatigue are major contributors to deficits in deglutitive function with age. We further hypothesize that tongue exercise can mitigate these fatigue- and age-related deficits. We will gain insight into mechanisms of tongue muscle fatigue by addressing specific hypotheses for each of our aims in a rat model. We will create both mild and moderate levels of tongue muscle fatigue using neuromuscular electrical stimulation prior to performing: 1) physiological assays of muscle contractile function and capillary blood flow; 2) biological assays of muscle bioenergetics; and, 3) behavioral and biomechanical measures of swallowing in young adult and old rats that have undergone tongue (or sham control) exercise. Our tongue exercise program is modeled after those used in current clinical practice. We have 3 specific aims: Aim 1 will test the hypotheses that tongue muscle fatigue increases with age, is exacerbated by fatigue in an age-dependent manner, and is rescued by tongue exercise; Aim 2 will quantify bioenergetic mechanisms of extrinsic and intrinsic tongue muscles to test the hypothesis that biological variables associated with fatigue degrade with aging and normalize with tongue exercise; and Aim 3 will test the hypotheses that deglutition outcomes are negatively affected by aging and fatigue, and are mitigated by tongue exercise. Our neuromuscular model is the first to evaluate adaptation in bioenergetic pathways with age and exercise in muscles of the tongue. The proposed research will provide a new understanding of mechanisms that underlie age-related tongue muscle fatigue from a physiological perspective, the relationship of structural changes to physiological function, and the effectiveness of lingual exercise as an intervention for muscle fatigue. This work is highly significant due to the large and increasing population of aging people who will benefit from treatments optimized in pre-clinical studies to address often-debilitating deglutition impairments.