State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources & Lingnan Guangdong Laboratory of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Laboratory of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou 510642, China.
Int J Mol Sci. 2022 Jun 21;23(13):6892. doi: 10.3390/ijms23136892.
Disuse muscle atrophy is identified as the physiological, biochemical, morphological, and functional changes during restricted movement, immobilization, or weightlessness. Although its internal mechanism has been extensively studied in mammals and was thought to be mainly related to oxidative stress, it was unclear whether it behaved consistently in non-mammals such as chickens. In this study, we tried to construct a disuse atrophy model of the gastrocnemius muscle in chickens by limb immobilization, and collected the gastrocnemius muscles of the fixed group and the control group for RNA sequencing. Through analysis of muscle loss, HE staining, immunohistochemistry, and oxidative stress level, we found that limb immobilization could lead to loss of muscle mass, decrease in muscle fiber diameter, decrease in the proportion of slow muscle fibers, and increase in the proportion of fast muscle fibers, and also cause elevated levels of oxidative stress. In addition, a total of 565 different expression genes (DEGs) were obtained by RNA sequencing, which was significantly enriched in the biological processes such as cell proliferation and apoptosis, reactive oxygen species metabolism, and fast and slow muscle fiber transformation, and it showed that the FOXO signaling pathway, closely related to muscle atrophy, was activated. In brief, we initially confirmed that limb immobilization could induce disuse atrophy of skeletal muscle, and oxidative stress was involved in the process of disuse muscle atrophy.
废用性肌肉萎缩是指在限制运动、固定或失重期间发生的生理、生化、形态和功能变化。尽管其内在机制在哺乳动物中已得到广泛研究，并且被认为主要与氧化应激有关，但在非哺乳动物（如鸡）中是否表现一致尚不清楚。在本研究中，我们试图通过肢体固定来构建鸡腓肠肌废用性萎缩模型，并收集固定组和对照组的腓肠肌进行 RNA 测序。通过肌肉损失、HE 染色、免疫组织化学和氧化应激水平分析，我们发现肢体固定可导致肌肉质量损失、肌纤维直径减小、慢肌纤维比例降低和快肌纤维比例增加，同时还会引起氧化应激水平升高。此外，通过 RNA 测序获得了总共 565 个差异表达基因（DEGs），这些基因在细胞增殖和凋亡、活性氧代谢以及快肌和慢肌纤维转化等生物学过程中显著富集，表明与肌肉萎缩密切相关的 FOXO 信号通路被激活。总之，我们初步证实了肢体固定可导致骨骼肌废用性萎缩，氧化应激参与了废用性肌肉萎缩过程。
