Department of Oral Maxillofacial Surgery, Kobe University Graduate School of Medicine, Japan.
Department of Oral Pathology and Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
PLoS One. 2024 Apr 17;19(4):e0302194. doi: 10.1371/journal.pone.0302194. eCollection 2024.
Cancer cachexia causes skeletal muscle atrophy, impacting the treatment and prognosis of patients with advanced cancer, but no treatment has yet been established to control cancer cachexia. We demonstrated that transcutaneous application of carbon dioxide (CO2) could improve local blood flow and reduce skeletal muscle atrophy in a fracture model. However, the effects of transcutaneous application of CO2 in cancer-bearing conditions are not yet known. In this study, we calculated fat-free body mass (FFM), defined as the skeletal muscle mass, and evaluated the expression of muscle atrophy markers and uncoupling protein markers as well as the cross-sectional area (CSA) to investigate whether transcutaneous application of CO2 to skeletal muscle could suppress skeletal muscle atrophy in cancer-bearing mice. Human oral squamous cell carcinoma was transplanted subcutaneously into the upper dorsal region of nude mice, and 1 week later, CO2 gas was applied to the legs twice a week for 4 weeks and FFM was calculated by bioimpedance spectroscopy. After the experiment concluded, the quadriceps were extracted, and muscle atrophy markers (muscle atrophy F-box protein (MAFbx), muscle RING-finger protein 1 (MuRF-1)) and uncoupling protein markers (uncoupling protein 2 (UCP2) and uncoupling protein 3 (UCP3)) were evaluated by real-time polymerase chain reaction and immunohistochemical staining, and CSA by hematoxylin and eosin staining. The CO2-treated group exhibited significant mRNA and protein expression inhibition of the four markers. Furthermore, immunohistochemical staining showed decreased MAFbx, MuRF-1, UCP2, and UCP3 in the CO2-treated group. In fact, the CSA in hematoxylin and eosin staining and the FFM revealed significant suppression of skeletal muscle atrophy in the CO2-treated group. We suggest that transcutaneous application of CO2 to skeletal muscle suppresses skeletal muscle atrophy in a mouse model of oral squamous cell carcinoma.
癌症恶病质导致骨骼肌萎缩，影响晚期癌症患者的治疗和预后，但目前尚无控制癌症恶病质的方法。我们证明，二氧化碳（CO2）经皮应用可以改善骨折模型中的局部血流并减少骨骼肌萎缩。然而，CO2 经皮应用于荷瘤状态的效果尚不清楚。在这项研究中，我们计算了去脂体重（FFM），定义为骨骼肌量，并评估了肌肉萎缩标志物和解偶联蛋白标志物的表达以及横截面积（CSA），以研究 CO2 是否可以抑制荷瘤小鼠的骨骼肌萎缩。将人口腔鳞状细胞癌皮下移植到裸鼠的上背部区域，1 周后，每周两次将 CO2 气体应用于腿部 4 周，并通过生物阻抗光谱法计算 FFM。实验结束后，提取股四头肌，通过实时聚合酶链反应和免疫组织化学染色评估肌肉萎缩标志物（肌肉萎缩 F-box 蛋白（MAFbx）、肌肉 RING 指蛋白 1（MuRF-1））和解偶联蛋白标志物（解偶联蛋白 2（UCP2）和解偶联蛋白 3（UCP3）），并通过苏木精和伊红染色评估 CSA。CO2 处理组这四个标志物的 mRNA 和蛋白表达均明显受到抑制。此外，免疫组织化学染色显示 CO2 处理组的 MAFbx、MuRF-1、UCP2 和 UCP3 减少。事实上，CO2 处理组的苏木精和伊红染色 CSA 和 FFM 显示出骨骼肌萎缩的显著抑制。我们认为，CO2 经皮应用于骨骼肌可抑制口腔鳞状细胞癌小鼠模型中的骨骼肌萎缩。
