Musculoskeletal Disorders Research Laboratory, Bioengineering Division, Department of Orthopedic Surgery, University of Colorado at Denver and Health Sciences Center, Aurora, CO 80045, USA.
Spine J. 2010 Dec;10(12):1078-85. doi: 10.1016/j.spinee.2010.08.030. Epub 2010 Oct 12.
Cumulative (repetitive) lumbar disorder is common in the workforce, and the associated epidemiology points out high risk for lifting heavy loads, performing many repetitions, and performing movements at high velocity. Experimental verification of viscoelastic tissue degradation and a neuromuscular disorder exist for cyclic work under heavy loads. Experimental validation for a disorder because of cyclic loads under high-velocity movement is missing.
Obtain experimental verification that high-velocity lumbar flexion-extension results in significant increase of proinflammatory cytokines in the viscoelastic tissues.
Laboratory experiments using two in vivo feline model groups subjected to cyclic flexion-extension at low and high velocity.
Seven hours after cumulative 60 minutes of cyclic flexion-extension at moderate load of 40 N and 0.25 Hz for first group and 0.5 Hz for the second group, the supraspinous ligaments of L3-L4 to L5-L6 were harvested and subjected to cytokines (interleukin [IL]-1β, IL-6, IL-8, tumor necrosis factor-α, and transforming growth factor-β1) analysis. Two-way mixed model analysis of variance with a post hoc analysis were used to assess any significant differences (p<.05) in cytokines expression level between the two groups as well as main effect and interaction with lumbar levels.
Expression levels of the five cytokines were significantly increased in the group subjected to the high-frequency loading.
Exposure of the lumbar spine to high-velocity flexion-extension triggers a significant increase in proinflammatory cytokines, indicating pronounced changes consistent with an acute inflammation. Further exposure to activity over prolonged periods may trigger chronic inflammation and tissue degeneration as the source of cumulative lumbar disorder.
累积性（重复性）腰椎疾病在劳动力中很常见，相关流行病学指出，高风险因素包括举重物、多次重复、高速运动。实验验证了在重负荷下进行周期性工作时，粘弹性组织降解和神经肌肉紊乱的存在。由于缺乏高速运动下周期性负荷引起的紊乱的实验验证，本研究旨在获得实验验证，证明高速腰椎屈伸会导致粘弹性组织中促炎细胞因子显著增加。
使用两个体内猫模型组进行实验室实验，这些模型组分别在低和高速下进行周期性屈伸。
在第一组中，在中度负荷 40N 和 0.25Hz 下进行 60 分钟累积循环屈伸 7 小时后，收获 L3-L4 至 L5-L6 的棘上韧带，并进行细胞因子（白细胞介素[IL]-1β、IL-6、IL-8、肿瘤坏死因子-α和转化生长因子-β1）分析。使用双向混合模型方差分析和事后分析来评估两组之间细胞因子表达水平的任何显著差异（p<.05），以及与腰椎水平的主效应和相互作用。
在接受高频加载的组中，五种细胞因子的表达水平显著增加。
腰椎暴露于高速屈伸会引发促炎细胞因子的显著增加，表明与急性炎症一致的明显变化。进一步长时间暴露于活动可能会引发慢性炎症和组织退化，成为累积性腰椎疾病的根源。
