title: Morphological and histological changes of rabbit vocal fold after steroid injection.
abstract: OBJECTIVE
  The purpose of this study was to investigate the morphological and histological change of vocal folds (VFs) after steroid injection in a rabbit model.
  
  
  METHODS
  Prospective animal study.
  
  
  METHODS
  Tertiary academic medical center.
  
  
  METHODS
  Twenty-four New Zealand white rabbits were used in this study. We randomly classified rabbits into the 3 groups and triamcinolone acetonide suspension was injected to the right VF with different concentrations. Left VF was injected with the same volume of phosphate-buffered saline as control. Endoscopic evaluation was performed to measure morphological changes. The larynges were collected for histological analysis, and the VFs were stained with hematoxylin-eosin for assessing inflammatory response, glandular atrophy, and muscular atrophy and with Masson's trichrome for assessing collagen deposition.
  
  
  RESULTS
  In morphological assessment, there were no differences in VF mass reduction, mucosal atrophy, and granulation formation between both VFs. Histological assessments showed no significant difference in inflammatory response, glandular atrophy, and collagen deposition between both VFs. However, there was a difference in muscular atrophy and epithelial layer thinning in steroid injected right VFs. Muscular atrophy had been completely recovered over time, but mild epithelial thinning was continued until 12 weeks. The longer exposure time and larger dose did not increase the intensity of muscular atrophy or epithelial thinning.
  
  
  CONCLUSIONS
  We demonstrated that the VF steroid injection resulted in no significant changes in morphology and histology of rabbit VF. However, steroid injection may induce several VF histological changes and these results are needed to be considered when treating humans.
authors.affiliation: School of Media and Communication, Korea University, Seoul, Korea.
authors.forename: Hee-Jin
authors.initials: HJ
authors.lastname: Jin
authors.forename: Sang-Hyuk
authors.initials: SH
authors.lastname: Lee
authors.forename: Seon-Uk
authors.initials: SU
authors.lastname: Lee
authors.forename: Hyun-Sub
authors.initials: HS
authors.lastname: Lee
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Jin
authors.forename: Dong-Hun
authors.initials: DH
authors.lastname: Kim
authors.forename: Seung-Wan
authors.initials: SW
authors.lastname: Chae
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Sohn
mesh_terms: D000818:Animals; D001284:Atrophy / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D003094:Collagen / Q000032:analysis; D004195:Disease Models, Animal; D005938:Glucocorticoids / Q000008:administration & dosage / Q000009:adverse effects; D007267:Injections; D007818:Laryngeal Diseases / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D007828:Laryngoscopy; D011446:Prospective Studies; D011817:Rabbits; D012720:Severity of Illness Index; D014222:Triamcinolone Acetonide / Q000008:administration & dosage / Q000009:adverse effects*; D014827:Vocal Cords / Q000737:chemistry / Q000187:drug effects / Q000473:pathology*; D014945:Wound Healing
chemical_list: D005938:Glucocorticoids; D003094:Collagen; D014222:Triamcinolone Acetonide
keywords: injections; rabbit; steroids; vocal folds