Role Of BDNF-trkB Signaling In Rat Cerebello-vestibular Pathway During Vestibular Compensation

Objective To observe the change in expression of brain-derived neurotrophicfactor (BDNF), tyrosine receptor kinase B (TrkB).FL, TrkB.T1and K+/Cl-cotransporter isoform2(KCC2) in rat medial vestibular nucleus (MVN) followingunilateral labyrinthectomy (UL). Methods The immunohistochemistry, Western-blotand quantitative real-time PCR techniques were used to observe the changes inexpressions of BDNF, TrkB.FL, TrkB.T1and KCC2in the MVN following UL andinvestigate their effects and possible mechanisms during vestibular compensation.Results Our results demonstrated that BDNF, TrkB.FL, TrkB.T1and KCC2were presented in the MVN. In the ipsilateral MVN, the BDNF and TrkB.FLexpression underwent a large and significant increase at8h after UL comparedwith contralateral side and control group, while at the1st to7th day after ULthe difference was no longer present. The KCC2, however, decreased at8hafter UL compared with contra-lesional side and control group whereas theexpression of TrkB.T1have no relative changes over time after UL.Conclusion Our study suggests that BDNF in ipsilateral MVN may participate inthe plasticity of the central vestibular system in the early stage of vestibularcompensation by binding to TrkB.FL, and KCC2is a switch in the process. Objective To observe the changes in expression of brain-derived neurotrophic factor(BDNF), tyrosine receptor kinase B (TrkB).FL, TrkB.T1and K+/Cl-cotransporterisoform2(KCC2) in rat flocculus following unilateral labyrinthectomy (UL).Methods The immunohistochemistry, Western-blot and quantitative real-time PCRtechniques were used to observe the changes in expressions of BDNF, TrkB.FL,TrkB.T1and KCC2in the flocculus following UL and investigate their effects andpossible mechanisms during vestibular compensation. Results Our resultsdemonstrated that BDNF, TrkB.FL, TrkB.T1and KCC2were presented in the flocculus.The expression of BDNF and TrkB.FL in the ipsi-lesional flocculus significantlyincreased compared with contra-lesional side and control group at the4h afterUL, and the differences disappeared at8h after UL. In addition, the expressionof TrkB.T1decreased at4h after UL and that of KCC2decreased at8h and the1st day after UL compared with contra-lesional side and control group.Conclusion Our study suggests that BDNF in ipsilateral flocculus may participatein the plasticity of the central vestibular system in the early stage of vestibularcompensation by binding to TrkB.FL and TrkB.T1, and KCC2is a switch in theprocess.