Voss Joachim G, Shagal Ayelet Goldshmid, Tsuji Joyce M, MacDonald James W, Bammler Theo K, Farin Fred M, St Pierre Schneider Barbara
Joachim G. Voss, PhD, RN, ACRN, FAAN, is Professor and Director, Sarah Cole Hirsh Institute for Evidence-Based Practice, Frances Payne Bolton School of Nursing, Case Western Reserve University, Cleveland, Ohio. Ayelet Goldshmid Shagal, BS, MS, is PhD student, Department of Microbiology, Immunology & Genetics, Faculty of Health Sciences, Ben Gurion University, Beer-Sheva, Israel. Joyce M. Tsuji, BS, MS, is Research Scientist, Department of Biological Structure, School of Medicine, University of Washington, Seattle. James W. MacDonald, PhD, is Research Scientist, Environmental Health, University of Washington, Seattle. Theo K. Bammler, PhD, is Research Scientist; and Fred M. Farin, MD, is Research Scientist, Environmental Health, University of Washington, Seattle. Barbara St. Pierre Schneider, PhD, RN, CNE, is Research Professor, School of Nursing, University of Nevada, Las Vegas.
Nurs Res. 2017 Mar/Apr;66(2):63-74. doi: 10.1097/NNR.0000000000000209.
Early inflammation and secretion of proinflammatory cytokines such as IL-1β, IL-6, and TNF-α act as the key drivers to regulate inflammation after muscle injury. However, the effects of these key proinflammatory drivers in a noninvasive crush injury model are not well known. Understanding these effects is important for treating crush injuries that occur during natural disasters and military conflicts.
We studied the timed mRNA expression of IL-1β, IL-6, and TNF-α in a noninvasive murine crush injury model to further understand their impact on proinflammatory cytokine pathways that are activated within the first 48 hours after a crush muscle injury.
A total of 25 mice were anesthetized and placed on a crush injury apparatus platform with the apparatus piston situated in direct contact with intact skin overlying the right gastrocnemius muscle. Pressure at 45 psi was applied to the piston for 30 seconds for two applications. The mice recovered for either 4, 8, 24, or 48 hours postinjury, after which we harvested the gastrocnemius muscle of both legs. Microarray, confirmatory real-time polymerase chain reaction, and immunolabeling experiments were followed by a microarray time-course analysis.
Muscle IL-1β mRNA rose 270-fold within 4 hours and declined rapidly at 8 hours to 196-fold, 24 hours to 96-fold, and 48 hours to 10-fold. Muscle IL-6 followed the same pattern, with a 34-fold increase at 4 hours, 29-fold increase at 8 hours, 10-fold increase at 24 hours, and 5-fold increase at 48 hours. Ingenuity Pathway Analysis of IL-6 identified activation of two major downstream signaling pathways (IL-6/Stat3 and IL-1β/Egr1) as key activators of inflammation, regeneration, and fibrosis.
Closed crush muscle injury produced robust muscle cytokine expression levels, and the microarray findings allowed us to generate our most novel hypothesis: that high expression of IL-1β, IL-6, and TNF-α may be related to the downregulation of mitochondrial genes early after injury and triggers activation of genes in the repair and fibrosis machinery. The significance of these findings and the identified expression pathways of IL1-β, IL-6, and TNF-α and their downstream targets in skeletal muscle will allow us to further investigate targets for improved muscle recovery and limb-saving interventions.
早期炎症以及白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）等促炎细胞因子的分泌，是调节肌肉损伤后炎症的关键驱动因素。然而，这些关键促炎驱动因素在非侵入性挤压伤模型中的作用尚不清楚。了解这些作用对于治疗自然灾害和军事冲突期间发生的挤压伤很重要。
我们研究了非侵入性小鼠挤压伤模型中IL-1β、IL-6和TNF-α的定时mRNA表达，以进一步了解它们对挤压肌肉损伤后48小时内激活的促炎细胞因子途径的影响。
总共25只小鼠麻醉后置于挤压伤装置平台上，装置活塞直接接触右腓肠肌上方的完整皮肤。对活塞施加45磅力/平方英寸的压力30秒，重复两次。小鼠在受伤后恢复4、8、24或48小时，之后我们采集双腿的腓肠肌。进行微阵列、验证性实时聚合酶链反应和免疫标记实验，随后进行微阵列时间进程分析。
肌肉IL-1β mRNA在4小时内升高270倍，8小时迅速下降至196倍，24小时降至96倍，48小时降至10倍。肌肉IL-6遵循相同模式，4小时增加34倍，8小时增加29倍，24小时增加10倍，48小时增加5倍。对IL-6的 Ingenuity 通路分析确定了两个主要下游信号通路（IL-6/Stat3和IL-1β/Egr1）的激活是炎症、再生和纤维化的关键激活剂。
闭合性挤压肌肉损伤产生了强大的肌肉细胞因子表达水平，微阵列研究结果使我们能够提出最新颖的假设：IL-1β、IL-6和TNF-α的高表达可能与损伤后早期线粒体基因的下调有关，并触发修复和纤维化机制中基因的激活。这些发现的意义以及在骨骼肌中确定的IL1-β、IL-6和TNF-α及其下游靶点的表达途径，将使我们能够进一步研究改善肌肉恢复和保肢干预的靶点。
