Division of Basic Sciences, College of Liberal Studies, Dong-Eui University, Busan 47340, Korea.
Department of Biochemistry, College of Korean Medicine, Dong-Eui University, Busan 47227, Korea.
Int J Mol Sci. 2021 Oct 29;22(21):11729. doi: 10.3390/ijms222111729.
Mori Ramulus, the dried twigs of L., has been attracting attention for its potent antioxidant activity, but its role in muscle cells has not yet been elucidated. The purpose of this study was to evaluate the protective effect of aqueous extracts of Mori Ramulus (AEMR) against oxidative stress caused by hydrogen peroxide (HO) in C2C12 mouse myoblasts, and in dexamethasone (DEX)-induced muscle atrophied models. Our results showed that AEMR rescued HO-induced cell viability loss and the collapse of the mitochondria membrane potential. AEMR was also able to activate AMP-activated protein kinase (AMPK) in HO-treated C2C12 cells, whereas compound C, a pharmacological inhibitor of AMPK, blocked the protective effects of AEMR. In addition, HO-triggered DNA damage was markedly attenuated in the presence of AEMR, which was associated with the inhibition of reactive oxygen species (ROS) generation. Further studies showed that AEMR inhibited cytochrome release from mitochondria into the cytoplasm, and Bcl-2 suppression and Bax activation induced by HO. Furthermore, AEMR diminished HO-induced activation of caspase-3, which was associated with the ability of AEMR to block the degradation of poly (ADP-ribose) polymerase, thereby attenuating HO-induced apoptosis. However, compound C greatly abolished the protective effect of AEMR against HO-induced C2C12 cell apoptosis, including the restoration of mitochondrial dysfunction. Taken together, these results demonstrate that AEMR could protect C2C12 myoblasts from oxidative damage by maintaining mitochondrial function while eliminating ROS, at least with activation of the AMPK signaling pathway. In addition, oral administration of AEMR alleviated gastrocnemius and soleus muscle loss in DEX-induced muscle atrophied rats. Our findings support that AEMR might be a promising therapeutic candidate for treating oxidative stress-mediated myoblast injury and muscle atrophy.
桑枝，桑科植物桑的干燥嫩枝，因其具有很强的抗氧化活性而受到关注，但它在肌肉细胞中的作用尚未阐明。本研究旨在评估桑枝水提物（AEMR）对过氧化氢（HO）诱导的 C2C12 小鼠成肌细胞和地塞米松（DEX）诱导的肌肉萎缩模型中氧化应激的保护作用。我们的结果表明，AEMR 可挽救 HO 诱导的细胞活力丧失和线粒体膜电位崩溃。AEMR 还能激活 HO 处理的 C2C12 细胞中的 AMP 激活的蛋白激酶（AMPK），而 AMPK 的药理学抑制剂 Compound C 阻断了 AEMR 的保护作用。此外，AEMR 显著减弱了 HO 触发的 DNA 损伤，这与活性氧（ROS）生成的抑制有关。进一步的研究表明，AEMR 抑制了 HO 诱导的细胞色素 c 从线粒体向细胞质的释放，以及 Bcl-2 抑制和 Bax 激活。此外，AEMR 减少了 HO 诱导的 caspase-3 的激活，这与 AEMR 阻断聚（ADP-核糖）聚合酶降解的能力有关，从而减轻了 HO 诱导的细胞凋亡。然而，Compound C 大大削弱了 AEMR 对 HO 诱导的 C2C12 细胞凋亡的保护作用，包括对线粒体功能障碍的恢复。综上所述，这些结果表明，AEMR 通过维持线粒体功能和消除 ROS 来保护 C2C12 成肌细胞免受氧化损伤，至少通过激活 AMPK 信号通路。此外，AEMR 口服给药可减轻 DEX 诱导的肌肉萎缩大鼠的比目鱼肌和跖肌损失。我们的研究结果支持 AEMR 可能是治疗氧化应激介导的成肌细胞损伤和肌肉萎缩的有前途的治疗候选物。
