Electroacupuncture improves swallowing function in a post-stroke dysphagia mouse model by activating the motor cortex inputs to the nucleus tractus solitarii through the parabrachial nuclei

Abstract

As a traditional medical therapy, stimulation at the Lianquan (CV23) acupoint, located at the depression superior to the hyoid bone, has been shown to be beneficial in dysphagia. However, little is known about the neurological mechanism by which this peripheral stimulation approach treats for dysphagia. Here, we first identified a cluster of excitatory neurons in layer 5 (L5) of the primary motor cortex (M1) that can regulate swallowing function in male mice by modulating mylohyoid activity. Moreover, we found that focal ischemia in the M1 mimicked the post-stroke dysphagia (PSD) pathology, as indicated by impaired water consumption and electromyographic responses in the mylohyoid. This dysfunction could be rescued by electroacupuncture (EA) stimulation at the CV23 acupoint (EA-CV23) in a manner dependent on the excitatory neurons in the contralateral M1 L5. Furthermore, neuronal activation in both the parabrachial nuclei (PBN) and nucleus tractus solitarii (NTS), which was modulated by the M1, was required for the ability of EA-CV23 treatment to improve swallowing function in male PSD model mice. Together, these results uncover the importance of the M1-PBN-NTS neural circuit in driving the protective effect of EA-CV23 against swallowing dysfunction and thus reveal a potential strategy for dysphagia intervention.

Participation of the nucleus tractus solitarius in the therapeutic effect of electroacupuncture on post‐stroke dysphagia through the primary motor cortex

“…Our previous study showed that swallowing function was impaired after NTS inhibition, and EA rescued the expression of c-Fos-positive neurons in PSD model mice, 25 which confirmed the role of the NTS in swallowing function. To further observe the role of the NTS in the regulation of swallowing function by M1, optogenetic activation and chemogenetic inhibition viruses (AAV2/9-CaMKIIα-ChR2, AAV2/9-CaMKIIα-hM4Di) were injected into the M1 and NTS, respectively (Figure 3A).…”

“…Data are presented as the mean ± SD, and n indicates the number of biologically independent samples (mice) per group.regulated by EA at CV23 in PSD mice,27 identifying a potential therapeutic target for the treatment of PSD. Our recent study revealed the function of the NTS in the treatment of EA in PSD model mice and its indirect role in the motor efferent neural circuit dominated by M1 25.…”

Clinical study on the efficacy of postural control combined with electroacupuncture in treating dysphagia after stroke

“…Previous studies indicate that acupuncture points for treating swallowing disorders after stroke include Lianquan (CV23), Tiantu (CV22), Chengjing (BL56), Chejia (ST6), Yifeng (TE17), Taixi (KI3), Fengchi (GB20), Neiguan (PC6), Sanyinjiao (SP6), Yintang (EX-HN3), Taiyang (EX-HN5), Jinjin (EX-HN12), Yuye (EX-HN13), Zusanli (ST36), Fenglong (ST40), Taichong (LR3), Xiaguan (ST7) ( 26 ). Among these, the most commonly used acupuncture points are Lianquan (CV23), Fengchi (GB20), Yifeng (TE17), Jinjin (EX-HN12), and Yuye (EX-HN13) ( 27 ).…”

“…Besides, Lianquan (CV23) acupoint as a peripheral stimulation strategy, could improve the swallowing function in PSD model mice through the activation of motor cortex inputs to the NTS through the PBN. the application of EA-CV23 for the treatment of PSD by addressing how motor cortex activation benefits recovery of swallowing function via a subcortical pathway, suggesting that acupuncture treatment could be used as an effective therapeutic intervention to improve swallowing function ( 27 ).…”

Unleashing the potential: integrating nano-delivery systems with traditional Chinese medicine

“…According to the theory of meridians and acupoints, acupuncture achieves therapeutic effects by inserting acupuncture needles into the corresponding acupoints. 113,114 Utilizing nano-delivery systems to incorporate biologically active ingredients onto the surface of stainless steel needles allows for the simultaneous release of these ingredients during the mechanical stimulation of acupuncture, thereby enhancing therapeutic efficacy. Xu and colleagues have made significant strides in the traditional acupuncture field by introducing a nanoenabled drug delivery acupuncture technology (nd-Acu) platform.…”