Transcriptome analysis of molecular mechanisms underlying facial nerve injury repair in rats

Although the transcriptional alterations inside the facial nucleus after facial nerve injury have been well studied,the gene expression changes in the facial nerve trunk after injury are still unknown.In this study,we established an adult rat model of facial nerve crush injury by compressing the right lateral extracranial nerve trunk.Transcriptome sequencing,differential gene expression analysis,and cluster analysis of the injured facial nerve trunk were performed,and 39 intersecting genes with significant variance in expression were identified.Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway analyses of the 39 intersecting genes revealed that these genes are mostly involved in leukocyte cell-cell adhesion and phagocytosis and have essential roles in regulating nerve repair.Quantitative real-time polymerase chain reaction assays were used to validate the expression of pivotal genes.Finally,nine pivotal genes that contribute to facial nerve recovery were identified,including Arhgap30,Akr1b8,C5ar1,Csf2ra,Dock2,Hcls1,Inpp5d,Sla,and Spi1.Primary Schwann cells were isolated from the sciatic nerve of neonatal rats.After knocking down Akr1b8 in Schwann cells with an Akr1b8-specific small interfering RNA plasmid,expression levels of monocyte chemoattractant protein-1 and interleukin-6 were decreased,while cell proliferation and migration were not obviously altered.These findings suggest that Akr1b8 likely regulates the interaction between Schwann cells and macrophages through regulation of cytokine expression to promote facial nerve regeneration.This study is the first to reveal a transcriptome change in the facial nerve trunk after facial nerve injury,thereby revealing the potential mechanism underlying repair of facial nerve injury.This study was approved by the Animal Ethics Committee of Nantong University,China in 2018(approval No.S20180923-007).

Electroacupuncture Promotes Functional Recovery after Facial Nerve Injury in Rats by Regulating Autophagy via GDNF and PI3K/m TOR Signaling Pathway

Objective:To explore the mechanism of electroacupuncture(EA) in promoting recovery of the facial function with the involvement of autophagy,glial cell line-derived neurotrophic factor(GDNF),and phosphatidylinositol-3-kinase(PI3K)/mammalian target of rapamycin(mTOR) signaling pathway.Methods:Seventy-two male Sprague-Dawley rats were randomly allocated into the control,sham-operated,facial nerve injury(FNI),EA,EA+3-methyladenine(3-MA),and EA+GDNF antagonist groups using a random number table,with 12 rats in each group.An FNI rat model was established with facial nerve crushing method.EA intervention was conducted at Dicang(ST 4),Jiache(ST 6),Yifeng(SJ 17),and Hegu(LI 4) acupoints for 2 weeks.The Simone’s 10-Point Scale was utilized to monitor the recovery of facial function.The histopathological evaluation of facial nerves was performed using hematoxylin-eosin(HE) staining.The levels of Beclin-1,light chain 3(LC3),and P62 were detected by immunohistochemistry(IHC),immunofluorescence,and reverse transcriptionpolymerase chain reaction,respectively.Additionally,IHC was also used to detect the levels of GDNF,Rai,PI3K,and mTOR.Results:The facial functional scores were significantly increased in the EA group than the FNI group(P<0.05 or P<0.01).HE staining showed nerve axons and myelin sheaths,which were destroyed immediately after the injury,were recovered with EA treatment.The expressions of Beclin-1 and LC3 were significantly elevated and the expression of P62 was markedly reduced in FNI rats(P<0.01);however,EA treatment reversed these abnormal changes(P<0.01).Meanwhile,EA stimulation significantly increased the levels of GDNF,Rai,PI3K,and mTOR(P<0.01).After exogenous administration with autophagy inhibitor 3-MA or GDNF antagonist,the repair effect of EA on facial function was attenuated(P<0.05 or P<0.01).Conclusions:EA could promote the recovery of facial function and repair the facial nerve damages in a rat model of FNI.EA may exert this neuroreparative effect through mediating the release of GDNF,activating the PI3K/mTOR signaling pathway,and further regulating the autophagy of facial nerves.

Surgical Management of Traumatic Facial Paralysis:A Case Review Study

Objective To evaluate efficacy of surgical treatment in traumatic facial paralysis.Methods:Thirty-three cases were reviewed,including temporal bone fracture and iatrogenic facial nerve injury.All the patients were treated with various surgical methods according to their pathogeny.Results The mean percentage facial function improvement (House-Brackmann GradeⅠ-Ⅱ) was 86% in temporal bone fracture and function was improved after proper operation to iatrogenic facial nerve injury.Conclusions Patients with traumatic facial paralysis receive proved outcomes itreaed with proper surgical methods according to their particular condition of nerve injury.