诱导和人类劳力骨骼肌损伤评估

Summary

This article describes a safe and reliable method to induce and quantify exertional skeletal muscle damage in human subjects.

Abstract

通过自愿偏心（延长）收缩收缩引起的肌肉损伤提供了研究人类肌肉的适应和恢复的优秀典范。在这里我们讨论的离心运动协议的设计诱导四头肌肌肉，在力量，疼痛，和血浆肌酸激酶水平的变化标志着损害。因为它是在人参加演出，并消除了结果的种间翻译此法简单，伦理和适用广泛。科目的速度进行伸膝肌群的最大300离心收缩 120°/上等速测力秒。损害的程度是衡量使用强度的损失，疼痛，和血浆肌酸激酶水平的相对非侵入等速和等距的措施在几天后的锻炼。因此，它的应用，可向特定人群，以试图确定肌肉机制适应和再生。

Introduction

The overall goal of this procedure is to induce exertional damage to the quadriceps femoris muscles using voluntary lengthening (eccentric) contractions in human subjects.

Contraction-induced skeletal muscle damage is a common consequence of exercise that is marked by delayed onset muscle soreness¹, transient strength loss, and elevated muscle-specific enzymes in the blood². Exertional muscle damage is most pronounced following exercise to which the subject is unaccustomed, particularly when eccentric contractions are involved³. Exertional muscle damage is typically benign. Soreness subsides, and both serum proteins and strength typically return to pre-damage levels within a few days to weeks after the damaging insult. In extreme cases, exertional muscle damage can lead to a life-threatening syndrome know as rhabdomyolysis. However, exertional muscle damage is usually insufficient to cause clinical rhabdomyolysis in healthy individuals⁴ in the absence of compounding factors including heat stress, dehydration⁵, infection⁶ or rare genetic predispositions⁷.

Contraction-induced muscle damage is typically less severe than toxin-induced or freezing-induced injury, methods often used in rodent studies^8,9. Yet, contraction-induced injury provides a useful method to study the muscle damage response with notable advantages. First, it is a safe and ethical method for use with human subjects^1-3. Thus, interspecies translation of the results is not needed as data can be obtained directly from human subjects. Moreover, translating data obtained from rodent studies is very difficult given that the severity of injury seen in the rodent injury models exceeds the level of damage that would be ethical to induce in human subjects. Second, contraction-induced damage is commonly experienced and a natural process of exercise. Therefore, this mode of damage induction is useful for studying muscle damage in the context of exercise, adaptation to exercise as well as overt muscle injury. Here we describe a safe and reliable method to induce and evaluate skeletal muscle damage using lengthening contractions in humans.

Protocol

以下程序均符合杨百翰大学机构审查委员会（IRB）的标准。 1.准备收缩协议注意：下面的协议说明基于所述Biodex Advantage软件。导航软件和如果使用不同的系统操作所述测力计将是不同的。 等速强度测试协议为了使等速协议，开测功机控制软件的计算机上，并选择“协议”选项卡，然后在屏幕顶部的工具栏上的“记录”选项卡。从下拉列表?…

Representative Results

使用这里介绍的方法，基线酸胀，血清肌酸激酶活性和强度（等距和等速）测量是在7未受过训练的年轻男子。第二天，受试者接受了肌肉损伤上述离心收缩协议。为了提供肌肉损伤的指标，跟进的实力，疼痛和血清肌酸激酶活性的评估进行的。强度运动后以及24，48，72，和96小时后，立即进行测定。疼痛测定24，48，72，和运动后96小时。血清肌酸激酶在48和120小时的运动后…

Discussion

有几个步骤是获得本协议的预期效果的关键。首先，受试者必须充分熟悉到收缩的协议，特别是测力。要确保拍摄理解他们应该做的，给他们练习之前，数据采集强度测试的机会到底是什么。谁不熟悉充分使用这些程序的主体会显示损伤诱导下过天的学习曲线。这可以是一个混杂变量呈现强度测量无效。 图5从谁可能没有被正确熟悉的个人资料显示。本课题显示，由于越来越多的实力…

Materials

Biodex Dynomometer	Biodex Medical Systems	850-000	Other models are available and should produce similar results
Creatine Kinase kit	Sigma-Aldrich	MAK116
Serum Vacutainers	BD Bioscience	367812
Winged safety push button blood collection set	BD Bioscience	367338
Cryogenic vials	Sigma-Aldrich	V5007	We use the 2mL vials to store serum aliquots