title: Rehabilitation of surgically traumatized paranasal sinus mucosa using retinoic acid.
abstract: BACKGROUND
  Paranasal sinus mucosa that regenerates after surgical stripping is characterized by sparse, dysmorphic cilia. Although such dysfunctional mucosal changes are thought to be irreversible, the potential rehabilitation of deciliated mucosa by topical therapies has not been explored. This study evaluated the effect of topical retinoic acid (RA) in rehabilitating deciliated sinus mucosa that has regenerated after surgical stripping.
  
  
  METHODS
  Twelve New Zealand rabbits underwent bilateral maxillary sinus mucosal stripping and were allowed to remucosalize for 10 days. In the first treatment arm (n = 6), 0.01% RA was applied to the regenerated mucosa of the left maxillary sinus and an aqueous control was placed contralaterally. In the second treatment arm, the regenerated mucosa was surgically restripped bilaterally before applying RA and control. After 14 additional days, mucosa was harvested and examined by scanning electron microscopy for ciliary density, orientation, and morphology.
  
  
  RESULTS
  In the first treatment arm, no significant differences in ciliary density, orientation, or morphology were noted between RA-treated sinuses and controls. In the second arm, RA-treated sinuses showed improved ciliary density, morphology, and orientation compared with controls.
  
  
  CONCLUSIONS
  RA does not appear to significantly enhance ciliogenesis when applied after mucosal regeneration has occurred. However, if deciliated mucosa is restripped and allowed to regenerate in the presence of RA, ciliary ultrastructural features may be enhanced. RA may have therapeutic value in rehabilitating deciliated sinus mucosa when applied before mucociliary differentiation of regenerating mucosa.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Division of Rhinology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Man-Kit
authors.initials: MK
authors.lastname: Leung
authors.forename: Peter H
authors.initials: PH
authors.lastname: Hwang
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D008297:Male; D008443:Maxillary Sinus / Q000187:drug effects / Q000502:physiology / Q000601:surgery / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D009297:Nasal Mucosa / Q000187:drug effects / Q000502:physiology*; D010256:Paranasal Sinuses / Q000187:drug effects / Q000502:physiology / Q000601:surgery* / Q000648:ultrastructure; D011183:Postoperative Complications / Q000188:drug therapy / Q000534:rehabilitation*; D011817:Rabbits; D012038:Regeneration / Q000187:drug effects*; D014212:Tretinoin / Q000627:therapeutic use*; D014945:Wound Healing / Q000187:drug effects
chemical_list: D014212:Tretinoin