title: Homeostasis of hyaluronic acid in normal and scarred vocal folds.
abstract: OBJECTIVE
  Vocal fold scarring is one of the most challenging laryngeal disorders to treat. Hyaluronic acid (HA) is the main component of lamina propria, and it plays an important role in proper vocal fold vibration and is also thought to be important in fetal wound healing without scarring. Although several animal models of vocal fold scarring have been reported, little is known about the way in which HA is maintained in vocal folds. The purpose of this study was to clarify the homeostasis of HA by examining the expression of hyaluronan synthase (Has) and hyaluronidase (Hyal), which produce and digest HA, respectively.
  
  
  METHODS
  Experimental prospective animal study.
  
  
  METHODS
  Vocal fold stripping was performed on 38 Sprague-Dawley rats. Vocal fold tissue was collected at five time points (3 days-2 months). Expression of HA was examined by immunohistochemistry, and messenger RNA (mRNA) expression of Has and Hyal was examined by real-time polymerase chain reaction and in-situ hybridization.
  
  
  RESULTS
  In scarred vocal folds, expression of Has1 and Has2 increased at day 3 together with expression of HA and returned to normal at 2 weeks. At 2 months, Has3 and Hyal3 mRNA showed higher expressions than normal.
  
  
  CONCLUSIONS
  Expression patterns of Has and Hyal genes differed between normal, acute-scarred, and chronic-scarred vocal folds, indicating the distinct roles of each enzyme in maintaining HA. Continuous upregulation of Has genes in the acute phase may be necessary to achieve scarless healing of vocal folds.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. Electronic address: tateya@ent.kuhp.kyoto-u.ac.jp.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tateya
authors.affiliation: Institute for Virus Research, Kyoto University, Kyoto, Japan; The Hakubi Center, Kyoto University, Kyoto, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tateya
authors.affiliation: AR-Ex Oyamadai Orthopedic Clinic, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Watanuki
authors.affiliation: Division of Otolaryngolosgy-Head & Neck Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Diane M
authors.initials: DM
authors.lastname: Bless
mesh_terms: D000818:Animals; D002921:Cicatrix / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D006706:Homeostasis / Q000502:physiology*; D006820:Hyaluronic Acid / Q000096:biosynthesis / Q000235:genetics*; D007150:Immunohistochemistry; D008297:Male; D011446:Prospective Studies; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D064706:Vocal Cord Dysfunction / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D014827:Vocal Cords / Q000378:metabolism* / Q000473:pathology
chemical_list: D012333:RNA, Messenger; D006820:Hyaluronic Acid
keywords: Hyaluronan synthase; Hyaluronic acid; Hyaluronidase; Scar; Vocal folds