title: Spontaneous healing of the tympanic membrane after traumatic perforation in rats.
abstract: The most common etiologies of tympanic membrane perforation are infections and trauma.
  
  
  OBJECTIVE
  The objective of the present study was to assess the healing of traumatic tympanic membrane perforation in rats.
  
  
  METHODS
  The tympanic membrane from male Wistar rats was perforated in the anterior and posterior portions to the handle of the malleus. Five tympanic membranes were evaluated 3 days after tympanic perforation; 5 after 5 days; 5 after 7 days; 3 after 10 days; and 4 after 14 days. The tympanic membranes were submitted to histopathological evaluation after hematoxylin-eosin staining.
  
  
  RESULTS
  Tympanic membrane closure occurred at about 7-10 days after injury and the healing process was complete by day 14. The proliferative activity of the outer epithelial layer was present close to the handle of the malleus and to the tympanic annulus.
  
  
  CONCLUSIONS
  The spontaneous healing process of the tympanic membrane starts from the outer epithelial layer, with later healing of the lamina propria and the mucosal layer.
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil. Electronic address: drmarcosorl@usp.br.
authors.forename: Marcos Miranda de
authors.initials: MM
authors.lastname: Araújo
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Adriana Andrade Batista
authors.initials: AA
authors.lastname: Murashima
authors.affiliation: Department of Cell and Molecular Biology and Pathogenic Bioagents, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Vani Maria
authors.initials: VM
authors.lastname: Alves
authors.affiliation: Department of Cell and Molecular Biology and Pathogenic Bioagents, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Maria Celia
authors.initials: MC
authors.lastname: Jamur
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
authors.forename: Miguel Angelo
authors.initials: MA
authors.lastname: Hyppolito
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D008297:Male; D009092:Mucous Membrane / Q000502:physiology*; D017208:Rats, Wistar; D013997:Time Factors; D018058:Tympanic Membrane Perforation / Q000473:pathology*; D014945:Wound Healing / Q000502:physiology*
keywords: Cicatrização; Histologia; Histology; Perfuração da membrana timpânica; Tympanic membrane perforation; Wound healing