Laboratory of Muscle Biology and Sarcopenia, Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506-9227, United States; West Virginia Center for Clinical and Translational Science Institute, West Virginia University School of Medicine, Morgantown, WV 26506-9227, United States; Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, WV 26506-9227, United States.
Laboratory of Muscle Biology and Sarcopenia, Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506-9227, United States; Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, WV 26506-9227, United States.
Exp Gerontol. 2014 Feb;50:82-94. doi: 10.1016/j.exger.2013.11.011. Epub 2013 Dec 3.
Aging exacerbates muscle loss and slows the recovery of muscle mass and function after disuse. In this study we investigated the potential that epigallocatechin-3-gallate (EGCg), an abundant catechin in green tea, would reduce signaling for apoptosis and promote skeletal muscle recovery in the fast plantaris muscle and the slow soleus muscle after hindlimb suspension (HLS) in senescent animals. Fischer 344 × Brown Norway inbred rats (age 34 months) received either EGCg (50 mg/kg body weight), or water daily by gavage. One group of animals received HLS for 14 days and a second group of rats received 14 days of HLS, then the HLS was removed and they recovered from this forced disuse for 2 weeks. Animals that received EGCg over the HLS followed by 14 days of recovery, had a 14% greater plantaris muscle weight (p<0.05) as compared to the animals treated with the vehicle over this same period. Plantaris fiber area was greater after recovery in EGCg (2715.2±113.8 μm(2)) vs. vehicle treated animals (1953.0±41.9 μm(2)). In addition, activation of myogenic progenitor cells was improved with EGCg over vehicle treatment (7.5% vs. 6.2%) in the recovery animals. Compared to vehicle treatment, the apoptotic index was lower (0.24% vs. 0.52%), and the abundance of pro-apoptotic proteins Bax (-22%), and FADD (-77%) was lower in EGCg treated plantaris muscles after recovery. While EGCg did not prevent unloading-induced atrophy, it improved muscle recovery after the atrophic stimulus in fast plantaris muscles. However, this effect was muscle specific because EGCg had no major impact in reversing HLS-induced atrophy in the slow soleus muscle of old rats.
衰老是肌肉损失加剧，并减缓废用后肌肉质量和功能的恢复。在这项研究中，我们研究了表没食子儿茶素没食子酸酯（EGCg），一种绿茶中的丰富儿茶素，是否可以减少凋亡信号并促进衰老动物后肢悬吊（HLS）后快速比目鱼肌和慢速比目鱼肌的骨骼肌肉恢复。接受 EGCg（50mg/kg 体重）或水每日灌胃的 Fischer 344×Brown Norway 近交系大鼠（34 月龄）。一组动物接受 14 天 HLS，另一组大鼠接受 14 天 HLS，然后去除 HLS，让它们从这种强制废用中恢复 2 周。在 HLS 期间接受 EGCg 治疗并随后在恢复期间接受治疗的动物，比在同一时期接受载体治疗的动物，比目鱼肌重量增加 14%（p<0.05）。在恢复期间，EGCg 处理的比目鱼肌纤维面积更大（2715.2±113.8μm²），而接受载体处理的动物（1953.0±41.9μm²）。此外，与载体处理相比，在恢复期间，用 EGCg 处理可改善成肌祖细胞的激活（7.5%比 6.2%）。与载体处理相比，凋亡指数更低（0.24%比 0.52%），并且在恢复后的 EGCg 处理的比目鱼肌中，促凋亡蛋白 Bax（-22%）和 FADD（-77%）的丰度更低。虽然 EGCg 不能防止去负荷引起的萎缩，但它改善了快速比目鱼肌在萎缩刺激后的肌肉恢复。然而，这种作用是肌肉特异性的，因为 EGCg 对老年大鼠慢速比目鱼肌的 HLS 诱导萎缩没有重大影响。
