Neuregulin1-ErbB4 Signaling Involved in Acupuncture Promoting Myelin Regeneration in Spinal Cord Injury Rats

Summary

This study aims to investigate the effects of electroacupuncture on myelin regeneration in a rat model of SCI and to verify whether the Neuregulin1 (NRG1)-ErbB4 signaling pathway plays a role in this process.

Abstract

Spinal cord injury (SCI) often results in severe neurological dysfunction, and myelin repair is a critical step in the recovery of neurological function. Electroacupuncture (EA), a therapeutic method that combines traditional acupuncture with electrical stimulation, has been widely applied in the field of nerve repair. However, the specific signaling pathways involved in EA have not been fully elucidated. This study aims to investigate the effects of EA on myelin regeneration in SCI rats and to verify whether the Neuregulin1 (NRG1)-ErbB4 signaling pathway plays a role in this process. SCI rats were induced by aneurysm clip injury at the T10 spinal segment. A polyethylene (PE) catheter was implanted into the vertebral canal between the L5-6 intervertebral spaces and fixed subcutaneously to establish a long-term drug delivery system. Exogenous NRG1 and its antagonist were administered through the PE catheter every other day, with a volume of 20 µL per injection. EA treatment was applied at the Dazhui (GV14) and Mingmen (GV4) acupuncture points every other day, each session lasting 30 min for 4 consecutive weeks. The results showed that EA treatment significantly promoted the expression of myelin basic protein (MBP) in spinal cord tissue and improved hind limb motor function in the rats. Furthermore, exogenous NRG1 produced similar effects to EA. In conclusion, the NRG1-ErbB4 signaling pathway plays an important role in EA-induced myelin regeneration in SCI rats.

Introduction

SCI is a traumatic condition that leads to severe neurological deficits, typically manifested by motor impairment, sensory loss, and autonomic dysfunction, with an annual incidence rate of approximately 40-80 cases per million people globally^1,2. Following injury, axonal rupture and myelin loss are the primary pathological features that impede neural signal conduction³. Myelin is formed by oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS), and its integrity is crucial for the rapid conduction of nerve impulses^....

Protocol

​All ethical guidelines were adhered to during the experiment to minimize animal suffering. The experimental protocol and design were approved by the Animal Experiment Committee of Kunming Medical University (Approval No. KMMU2021051) and conducted in accordance with the university's animal research guidelines. Adult male Sprague-Dawley rats (8 weeks old, weighing 250-270 g, n = 60) were obtained from Kunming Medical University (Yunnan, China).

Animal preparation

The animals were housed in a controlled environment with constant humidity, a moderate temperature, and a 12 h light/dark cyc....

Results

H&E staining and BBB scoring demonstrate the protective effects of EA on SCI rats

H&E staining was used to examine the morphology and structure of the posterior horn cells of the spinal cord (Figure 2D). The H&E results revealed that in group S, the posterior horn cells were neatly arranged, with well-defined cell outlines and centrally located nuclei. In contrast, the number of posterior horn cells was reduced in group M, with disorga.......

Discussion

This study demonstrates that EA treatment alleviates spinal cord cavitation and demyelination after SCI, promoting remyelination through upregulation of MBP protein expression, and consequently improves hindlimb motor function in rats. Furthermore, we identified the NRG-1/ErbB4 signaling pathway as a critical mediator of neuronal remyelination and a potential therapeutic mechanism through which EA promotes remyelination and recovery of hindlimb motor function in SCI rats.

Nerve conduction in S.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
BCA Protein Detection Kit	Beyotime Biotechnology	P0012S	Quantitative protein analysis
Electroacupuncture device	Huatuo Electroacupuncture Instrument, SDZ-V, Suzhou	—	Therapeutic equipment
FITC-labeled goat anti-human IgG	Beyotime	A0556	Fluorescent secondary antibody
FITC-labeled goat anti-mouse IgG	Beyotime	A0568	Fluorescent secondary antibody
FITC-labeled goat anti-rabbit IgG	Beyotime	A0562	Fluorescent secondary antibody
Fluorescence microscope	Olympus	—	—
Human monoclonal MBP	Abcam	ab209328	specific antibody
LFB myelin staining solution	Solarbio	G3240	myelin sheath staining
Millipore ECL	Millipore	WBKLS0100	Detection reagents
Mouse monoclonal NRG-1	Santa Cruz	SC-57384	specific antibody
Nanodrop ND-1000	LabTech	—
NRG1-1 beta	Novoprotein Technology Co	C753	Recombinant human NRG1-1 beta
PD158780	GlpBio Technology	GC15925	The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor
PE-10 conduit	Becton, Dickinson and Company	427401	intrathecal injection
Penicillin sodium for injection	Harbin Zhongjing Biotechnology Co	80451182	Postoperative anti-infection therapy
Rabbit monoclonal ErbB4	Abcam	ab109273	specific antibody
RNAiso Plus Kit	Takara	9109	RT-PCR reagents
RT Reagent Kit	Takara	RR037A	RT-PCR reagents
Secondary antibody	Beyotime Biotechnology	—	specific antibody
Sodium pentobarbital	Sigma-Aldrich	69020100	Animal anesthesia
Yasargil aneurysm clip	Rebstock Instruments GmbH	—	Construction of a rat spinal cord injury model