title: [Expression of Dynamin in the cochlea of mice of different ages].
abstract: OBJECTIVE
  To investigate the expression of Dynamin subtypes in inner hair cell (IHC) of mice, and to discuss their possible roles in age-related hearing loss.
  
  
  METHODS
  Auditory brainstem response (ABR) was recorded from the Kunming mice on postnatal 3 weeks (young), 10 weeks (adult), and 16 months (aged), 10 mice in each group. The expression of each Dynamin isoforms in the hair cells of the cochlea was observed by immunofluorescence staining and confocal microscope, and the transcription level of Dynamin subtypes mRNA was detected in qRT-PCR. Data analysis using SPSS 18 software.
  
  
  RESULTS
  ABR threshold showed no significant difference between the group of young and adult (t = -5.273, P = 0.076), but the threshold of the aged group increased comparing with young group (t = -8.365, P = 0.000), and adult group (t = -6.191, P = 0.000). All subtypes expressed in the inner hair cell of mice, of which Dynamin-1 and 2 expressed in the whole inner hair cell in the group of young and adult. In the aged group, Dynamin-1 was lost beneath the nucleus, and Dynamin-2 only be found near the nucleus. In addition, Dynamin-3 was scattered in the region of the basal part of the cells beneath the nucleus and near the spiral ganglion. The qRT-PCR revealed that mRNA of Dynamin-1 reduced with age (F = 10.410, P = 0.011), mRNA of Dynamin-2 increased to a peak in the adult group and then reduced with age (F = 24.575, P = 0.000). Meanwhile, mRNA of Dynamin-3 was not be detected.
  
  
  CONCLUSIONS
  All subtypes of Dynamin express in IHC. The expression of Dynamin-1 and 2 is up-regulated during maturity, which might alter the endocytosis of IHC; and the disorder of endocytosis might modulate the synaptic transmission of IHC. Whether Dynamin-3 plays a role in inner hair cells remains unclear because of the low expression.
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Cai
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Zhiji
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Gu
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Xueyuan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China; Email: weiyuan175@sina.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Yuan
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D003051:Cochlea / Q000378:metabolism*; D034281:Dynamins / Q000378:metabolism*; D016057:Evoked Potentials, Auditory, Brain Stem; D006199:Hair Cells, Auditory, Inner / Q000378:metabolism*; D051379:Mice
chemical_list: D034281:Dynamins