Abdominal ultrasound activates afferent vagus nerve fibers and induces anti-inflammatory effects
Abstract
Abdominal ultrasound has emerged as a noninvasive modality with immunomodulatory potential. Although its anti-inflammatory effects have been demonstrated in various disease models, the underlying mechanisms remain unclear. Previous studies suggest that ultrasound promotes anti-inflammatory macrophage polarization via α7 nicotinic acetylcholine receptor (α7nAChR) signaling in the spleen. However, the upstream events initiating this response have not been elucidated. Here, we demonstrate that abdominal ultrasound activates afferent vagal fibers and suppress systemic inflammation. In a murine model of lipopolysaccharide (LPS)-induced endotoxemia, abdominal ultrasound significantly reduced plasma TNF-α levels. This anti-inflammatory effect was attenuated by subdiaphragmatic vagotomy (SDVx) or afferent vagal blockade. Electrophysiological recordings revealed increased cervical vagus nerve activity during ultrasound stimulation, which was eliminated by intraperitoneal lidocaine, confirming activation of abdominal sensory afferents. Furthermore, abdominal ultrasound induced c-Fos expression in the nucleus tractus solitarius (NTS), consistent with central activation via vagal afferent input. These findings provide direct mechanistic evidence that abdominal ultrasound stimulates afferent vagal pathways.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (15)
Kotaro Shimoyama
Department of Physiology of Visceral Function and Body Fluid, Graduate School of Biomedical Sciences, Nagasaki University
Mamoru Tanida
Department of Physiology II, Kanazawa Medical University
Jun Aruga
Department of Medical Pharmacology, Nagasaki University Institute of Biomedical Sciences
Tomohiro Furusato
Graduate School of Integrated Science and Technology, Nagasaki University
Chia-Hsien Wu
Department of Physiology of Visceral Function and Body Fluid, Graduate School of Biomedical Sciences, Nagasaki University
Yasuna Nakamura
Department of Physiology of Visceral Function and Body Fluid, Graduate School of Biomedical Sciences, Nagasaki University
Daisuke Takahashi
Department of Physiology of Visceral Function and Body Fluid, Graduate School of Biomedical Sciences, Nagasaki University
Go Kanzaki
Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine
Atsuhiro Maeda
Department of Physiology of Visceral Function and Body Fluid, Graduate School of Biomedical Sciences, Nagasaki University
Takao Shioya
Department of Physiology, Faculty of Medicine, Saga University
Nobuo Tsuboi
Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine
Chikara Abe
Department of Physiology, University of Fukui School of Medical Sciences
Takashi Yokoo
Ryusuke Umene
Department of Physiology of Visceral Function and Body Fluid, Graduate School of Biomedical Sciences, Nagasaki University
Tsuyoshi Inoue