title: [Therapeutic effect of insulin-like growth factor-1 injection into the inner ears through scala tympani fenestration on gentamicin-induced hearing loss in guinea pigs].
abstract: OBJECTIVE
  To study the therapeutic effect of insulin-like growth factor-1 (IGF-1) injection into the inner ears through a scala tympani fenestration on sensorineural deafness in a guinea pig model of gentamicin-induced hearing loss.
  
  
  METHODS
  Twenty guinea pigs with gentamicin-induced hearing loss were randomized equally into IGF-1 group and control group. In both groups, scala tympani fenestration was performed for injection of IGF-1 (10 microl) or artificial perilymphatic fluid (10 microl). Auditory brainstem responses (ABR) test was performed before and 7 and 14 days after surgery, respectively, and the cochlea was removed by decollation of 3 guinea pigs from each group after ABR test for observing the changes in the hair cells using scanning electron microscope.
  
  
  RESULTS
  Significant reduction in the ABR response threshold (RT) occurred in IGF-1 group 7 and 14 days after the surgery, and on day 14, ABR RT showed significant difference between IGF-1 group and the control group. Scanning electron microscopy revealed severer damages of the hair cells in the control group, and in the IGF-1 group, finger-like microvilli was detected on the surface of the damaged hair cells.
  
  
  CONCLUSIONS
  IGF-1 injection in the inner ear through the scala tympani fenestration may ameliorate the damages of the auditory function and relieve sustained toxicity of gentamicin in guinea pigs possibly by protection and partial repair of the damaged cochlea hair cells as well as protection of the afferent nerves.
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China. Liyonghe517@163.com
authors.forename: Yong-he
authors.initials: YH
authors.lastname: Li
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Meng-he
authors.initials: MH
authors.lastname: Guo
mesh_terms: D000818:Animals; D007758:Ear, Inner / Q000187:drug effects* / Q000503:physiopathology; D005839:Gentamicins; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000648:ultrastructure; D034381:Hearing Loss / Q000139:chemically induced / Q000188:drug therapy*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D012533:Scala Tympani
chemical_list: D005839:Gentamicins; D007334:Insulin-Like Growth Factor I