title: Effect of trans-retinoic acid in the inhibition of cholesteatoma in guinea pigs.
abstract: Middle ear cholesteatoma affected more than 5 million people until the 80;s. Many animal models were used, unsuccessfully, to study an alternative therapy to cholesteatoma.
  
  
  OBJECTIVE
  observe the effect of the trans-retinoic acid in the inhibition of middle ear cholesteatomas induced by propylene glycol.
  
  
  METHODS
  Clinical and Experimental.
  
  
  METHODS
  25 guinea pigs were submitted to the application of a 100% propylene glycol solution in their bulla bilaterally and a solution of trans-retinoic acid was applied locally in the external right ear, while in the left ear saline solution was applied (control ear). The guinea pigs were slaughtered and their temporal bones were prepared for macroscopic and histological analysis.
  
  
  RESULTS
  The macroscopic findings had evidenced the presence of cholesteatoma in 25% of the right ears and 85% of the left ears (P=0.0003 *). The histological study had evidenced the presence of cholesteatoma in 30% of right ears and 75% of the left ears (P=0.0104*).
  
  
  CONCLUSIONS
  The local use of the trans-retinoic acid is effective in inhibiting the induced formation of cholesteatomas in guinea pigs.
authors.affiliation: Faculdade de medicina do ABC, SP, Brazil.
authors.forename: Marcos Luiz
authors.initials: ML
authors.lastname: Antunes
authors.forename: Yotaka
authors.initials: Y
authors.lastname: Fukuda
authors.forename: Norma de Oliveira
authors.initials: Nde O
authors.lastname: Penido
authors.forename: Rimarcs
authors.initials: R
authors.lastname: Ferreira
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D018424:Cholesteatoma, Middle Ear / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D004195:Disease Models, Animal; D005260:Female; D006168:Guinea Pigs; D008297:Male; D019946:Propylene Glycol; D011446:Prospective Studies; D014212:Tretinoin / Q000627:therapeutic use*
chemical_list: D000970:Antineoplastic Agents; D014212:Tretinoin; D019946:Propylene Glycol