Liu Xiaoguang, Zeng Zhigang, Zhao Linlin, Xiao Weihua, Chen Peijie
School of Kinesiology, Shanghai University of Sport, Shanghai 200438, P.R. China.
College of Physical Education, Jinggangshan University, Ji'an, Jiangxi 343009, P.R. China.
Exp Ther Med. 2018 Feb;15(2):2196-2202. doi: 10.3892/etm.2017.5625. Epub 2017 Dec 13.
Injury of skeletal muscle, and particularly mechanically-induced damage, including contusion injury, frequently occurs in contact sports as well as in sports with accidental contact. Although the mechanisms of skeletal muscle regeneration are well understood, those involved in muscle contusion are not. A total of 40 male mice were randomly divided into control (n=8) and muscle contusion (n=32) groups. A muscle contusion model was established by weight-drop injury. Subsequently, the gastrocnemius muscles in the two groups were harvested at different times (1, 3, 7 and 14 days) post-injury. The changes in skeletal muscle morphology were assessed by hematoxylin and eosin (H&E) stains. Furthermore, quantitative polymerase chain reaction and western blotting were used to analyze inflammatory cytokines, oxidative stress factors and the Akt/mechanistic target of rapamycin (mTOR) pathway. The results revealed that pro-inflammatory cytokines [tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interferon-γ (IFN-γ)] increased significantly at day 1 and 3 and still exhibited high levels of expression at days 7 and 14 (except IL-6) post-injury. Additionally, the anti-inflammatory cytokine IL-10 increased significantly at 1, 3 and 7 days and reached its peak levels at 7 days post-injury. It was revealed that gp91phox mRNA increased significantly at all time points and gp91phox protein increased significantly at day 3 post-injury. Furthermore, it was observed that p-Akt/Akt increased significantly at 1 day post-injury. P-mTOR/mTOR increased significantly at day 1 and 7, and p-p70s6k/p70s6k and P-4EBP1/4EBP1 increased significantly at 1, 3, 7 and 14 days post-injury. These results indicate that inflammatory and oxidative stress factors and the Akt/mTOR pathway may serve important roles in the regeneration of muscle contusion. In addition, certain inflammatory factors and oxidative stress factors maintained high levels of expression at 14 days after injury, indicating that the healing process of muscle was still not fully achieved at this time.
骨骼肌损伤，尤其是机械性损伤，包括挫伤，在接触性运动以及意外接触的运动中经常发生。虽然骨骼肌再生的机制已为人熟知，但肌肉挫伤所涉及的机制却并不清楚。总共40只雄性小鼠被随机分为对照组（n = 8）和肌肉挫伤组（n = 32）。通过重物坠落损伤建立肌肉挫伤模型。随后，在损伤后的不同时间点（1、3、7和14天）采集两组小鼠的腓肠肌。通过苏木精和伊红（H&E）染色评估骨骼肌形态的变化。此外，采用定量聚合酶链反应和蛋白质印迹法分析炎性细胞因子、氧化应激因子以及Akt/雷帕霉素作用靶点（mTOR）信号通路。结果显示，促炎细胞因子[肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）和干扰素-γ（IFN-γ）]在损伤后第1天和第3天显著增加，在第7天和第14天（IL-6除外）仍表现出高表达水平。此外，抗炎细胞因子IL-10在第1、3和7天显著增加，并在损伤后第7天达到峰值水平。结果表明，gp91phox mRNA在所有时间点均显著增加，gp91phox蛋白在损伤后第3天显著增加。此外，观察到p-Akt/Akt在损伤后第1天显著增加。P-mTOR/mTOR在第1天和第7天显著增加，p-p70s6k/p70s6k和P-4EBP1/4EBP1在损伤后第1、3、7和14天显著增加。这些结果表明，炎性和氧化应激因子以及Akt/mTOR信号通路可能在肌肉挫伤的再生中发挥重要作用。此外，某些炎性因子和氧化应激因子在损伤后14天仍维持高表达水平，表明此时肌肉的愈合过程仍未完全完成。
