Neurotrophic factors,or neurotrophins,are a group of molecules supporting the growth,survival,and differentiation of developing and mature neurons.Given their role in the survival of neurons,and often of specific subsets of brain cells,neurotrophins have been implicated in several ways with many neurodegenerative disorders.
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 P
YAO Jun-pengFENG Xiu-meiWANG LuLI Yan-qiuZHU Zi-yueYAN Xiang-yunYANG Yu-qingLI YingZHANG Wei
