Nagoya Kouta, Tsujimura Takanori, Yoshihara Midori, Watanabe Masahiro, Magara Jin, Kawasaki Katsushige, Inoue Makoto
Division of Oral Functional Rehabilitation Medicine, Department of Oral Health Management, Showa University School of Dentistry, Tokyo, Japan.
Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
Front Physiol. 2024 Aug 7;15:1445336. doi: 10.3389/fphys.2024.1445336. eCollection 2024.
Chronic obstructive pulmonary disease (COPD) was previously known as chronic bronchitis and emphysema. It has various main symptoms, such as dyspnea, chronic cough, and sputum, and is often accompanied by dysphagia. Although many published clinical reports have described COPD-related dysphagia, the physiological mechanisms underlying swallowing changes due to COPD remain unclear. Therefore, we analyzed how COPD affects the swallowing reflex using COPD model rats. We performed an electrophysiological study of respiration and swallowing using COPD model induced by intratracheal administration of porcine pancreatic elastase and lipopolysaccharide in Sprague-Dawley male rats. To identify the respiration and swallowing responses, electromyographic activity was recorded from the diaphragm, digastric (Dig), and thyrohyoid (TH) muscles. We confirmed COPD using micro-computed tomography analysis and hematoxylin and eosin staining of the lungs. The duty cycle was defined as the ratio of the inspiration duration to the total respiratory duration. In COPD model rats, the duty cycle was significantly higher than that in control rats. The frequency of the swallowing reflex evoked by electrical stimulation of the superior laryngeal nerve during the inspiration phase was higher in COPD model rats than in control rats. Furthermore, long-term COPD altered Dig and TH muscle activity without pathological muscle change. Our results suggest that COPD increases the frequency of swallowing initiation during the inspiration phase. Furthermore, long-term COPD affects swallowing-related muscle activity without pathological muscle changes. These physiological changes may increase the risk of developing dysphagia. Further studies are necessary to clarify the mechanisms contributing to the functional changes in respiration and swallowing in COPD.
慢性阻塞性肺疾病（COPD）以前被称为慢性支气管炎和肺气肿。它有多种主要症状，如呼吸困难、慢性咳嗽和咳痰，且常伴有吞咽困难。尽管许多已发表的临床报告描述了与COPD相关的吞咽困难，但COPD导致吞咽变化的生理机制仍不清楚。因此，我们使用COPD模型大鼠分析了COPD如何影响吞咽反射。我们对通过气管内注射猪胰弹性蛋白酶和脂多糖诱导的Sprague-Dawley雄性大鼠COPD模型进行了呼吸和吞咽的电生理研究。为了确定呼吸和吞咽反应，记录了膈肌、二腹肌（Dig）和甲状舌骨肌（TH）的肌电图活动。我们通过肺部的微计算机断层扫描分析和苏木精-伊红染色确认了COPD。占空比定义为吸气持续时间与总呼吸持续时间的比值。在COPD模型大鼠中，占空比显著高于对照大鼠。在吸气期，通过电刺激喉上神经诱发的COPD模型大鼠吞咽反射频率高于对照大鼠。此外，长期COPD改变了Dig和TH肌肉活动，但无病理性肌肉变化。我们的结果表明，COPD增加了吸气期吞咽起始的频率。此外，长期COPD影响与吞咽相关的肌肉活动，但无病理性肌肉变化。这些生理变化可能会增加发生吞咽困难的风险。有必要进一步研究以阐明导致COPD呼吸和吞咽功能变化的机制。
