title: Effects of topical intranasal doxycycline treatment in the rat allergic rhinitis model.
abstract: OBJECTIVE
  Allergic rhinitis (AR) is a chronic upper respiratory tract disease that inflames the mucous membranes of the nose and occurs when circulating inflammatory cells including eosinophils and basophils migrate to and accumulate in the inflammation area by passing through the interstitium and capillary walls. To pass through these barriers, the inflammatory cells degrade extracellular matrix proteins. Matrix metalloproteinases (MMPs) released by inflammatory cells mediate the degradation of these proteins. MMPs have synthetic inhibitors and doxycycline, a tetracycline antibiotic, inhibits MMPs. This study investigated the efficiency of intranasal doxycycline in decreasing the symptoms and inflammatory cell infiltration in an animal model of AR.
  
  
  METHODS
  AR was created in female Wistar rats by repeated intranasal challenge with ovalbumin by intraperitoneal injection. For 15 days, topical intranasal doxycycline was administered one hour before ovalbumin administration. Following intranasal administration, nasal symptoms were scored and the nasal mucosae of all rats were evaluated histopathologically. To investigate tissue changes, hematoxyline-eosin and Alcian blue/periodic acid Schiff stains were used. As well, cilia loss, goblet cell changes, vascular congestion, vascular proliferation, inflammatory cell infiltration, eosinophil infiltration and the degree of hypertrophy in chondrocytes were evaluated with light microscopy.
  
  
  RESULTS
  Typical symptoms of AR were decreased by intranasal doxycycline administration. These effects were stable after repeated intranasal ovalbumin administration. Histological evaluation of doxycycline treated rats did not reveal typical inflammatory changes associated with AR.
  
  
  CONCLUSIONS
  MMPs may have crucial functions in AR and topical intranasal doxycycline, which decreases inflammatory cell infiltration, may offer an alternative therapy for AR.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Private Gazi Hospital, Izmir, Turkey.
authors.forename: Mehmet Ozgür
authors.initials: MO
authors.lastname: Avincsal
authors.affiliation: Department of Histology and Embriyology, Dokuz Eylul University School of Medicine, Izmir, Turkey.
authors.forename: Seda
authors.initials: S
authors.lastname: Ozbal
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Dokuz Eylul University School of Medicine, Izmir, Turkey.
authors.forename: Ahmet Omer
authors.initials: AO
authors.lastname: Ikiz
authors.affiliation: Department of Histology and Embriyology, Dokuz Eylul University School of Medicine, Izmir, Turkey.
authors.forename: Cetin
authors.initials: C
authors.lastname: Pekcetin
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Dokuz Eylul University School of Medicine, Izmir, Turkey.
authors.forename: Enis Alpin
authors.initials: EA
authors.lastname: Güneri
keywords: Allergic rhinitis; Doxycycline; Matrix metalloproteinase inhibitors