Establishment of Facial Nerve Injury Rat Model for Idiopathic Facial Paralysis Research

Summary

The present protocol establishes a facial nerve injury rat model using microscopy to investigate the diagnostic and therapeutic mechanisms of idiopathic facial paralysis.

Abstract

Idiopathic facial paralysis is the most common type of facial nerve injury, accounting for approximately 70% of peripheral facial paralysis cases. This disease can not only lead to a change in facial expression but also greatly impact the psychology of patients. In severe cases, it can affect the normal work and life of patients. Therefore, the research on facial nerve injury repair has important clinical significance. In order to study the mechanism of this disease, it is necessary to carry out relevant animal experiments, among which the most important task is to establish an animal model with the same pathogenesis as human disease. The compression of the facial nerve within the petrous bone, especially the nerve trunk at the junction of the distal end of the internal auditory canal and the labyrinthine segment, is the pathogenesis of idiopathic facial paralysis. In order to simulate this common disease, a compression injury model of the main extracranial segment of the facial nerve was established in this study. The neurological damage was evaluated by behavioral, neuroelectrophysiological, and histological examination. Finally, 50 g constant force and 90 s clamp injury were selected as the injury parameters to construct a stable idiopathic facial paralysis model.

Introduction

As a type of peripheral facial paralysis, idiopathic facial paralysis is characteristic of unknown etiology, acute onset, and self-limiting course^1,2. The etiology and pathogenesis of idiopathic facial paralysis are still uncertain³. At present, there are various treatment methods for facial paralysis⁴, and the diversity of treatments reflects the lack of optimal treatment options. Using cellular and molecular biology techniques to study the mechanism of facial nerve injury is the foundation for establishing effective treatment methods for facial paralysis. There....

Protocol

All the animal experiments were approved and supervised by the Animal Ethics Committee of Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine (XHEC-F-2023-061). Sprague-Dawley male Rats, 200-300 g, were used for the present study. The animals were obtained from a commercial source (see Table of Materials). The rats were randomly divided into four groups (n = 10): Sham surgery group, 30-s injury group, 60-s injury group, and 90-s injury group.

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Discussion

It is necessary to study the repair mechanism of facial nerve injury in patients with idiopathic facial paralysis¹⁷. The degree of facial nerve injury model should meet the following requirements. Firstly, the degree of facial nerve injury should not be too mild, such as Sunderland Grade 1^st degree¹⁸, which can completely self-repair without drug intervention. Secondly, it should not be too severe, such as Sunderland 5th degree, which requires surgical interventi.......

Materials

Name	Company	Catalog Number	Comments
4% paraformaldehyde fixing solution	Beyotime Biotechnology	P0099
Clean bench	Airtech
Electronic balance	Shanghai Precision Instrument Factory	AS909
Freezing microtome	Leica	CM1900
Hematoxylin eosin (HE) staining kit	Beyotime Biotechnology	C0105S
Ketamine	Sigma	57074-21-2
Optical photographic microscope	Olympus	IX90
Pentobarbital sodium	ChemSrc	57-33-0
Quantitative peripheral nerve injury forceps	In-house		Patent number: CN20082015530.3
Sprague-Dawley rats	Jiangsu Jicui Yaokang Biotechnology Co., Ltd
Surgical operating microscope	OPMI 1FR proergo	ZEISS