title: Inhibitory effect of N-acetyl cysteine and ascorbic acid on the development of myringosclerosis: an experimental study.
abstract: OBJECTIVE
  This study investigated the effects of ascorbic acid and N-acetyl cysteine (NAC) antioxidants on the development of myringosclerosis (MS) in an experimental model.
  
  
  METHODS
  Myringotomies were performed in the ears of 15 guinea pigs, and Spongostan pieces were placed on the perforated regions of the tympanic membrane. The subjects were divided randomly into three groups and treated with three different solutions on the Spongostan-group 1: (control, 0.9% saline), group 2 (ascorbic acid), and group 3 (NAC). On day 15 after treatment, specimens from the tympanic membranes were obtained and examined via light microscopy. Sclerosis and inflammation scores and the tympanic membrane thicknesses were evaluated. Immunohistochemical methods were used to evaluate the expression of VEGF, TGF-β, iNOS, and IL1-β in all groups.
  
  
  RESULTS
  Lower sclerosis and inflammation scores and reduced tympanic membrane thicknesses were observed in groups treated with NAC or ascorbic acid compared with the control group. Immunohistochemical studies revealed significantly less expression of VEGF, TGF-β, and iNOS in groups 2 and 3 compared with group 1. Additionally, IL1-β expression was significantly less in group 3 than in group 1. Compared with group 1, group 2 animals exhibited reduced inflammation in the lamina propria, fewer active fibroblasts, less leukocyte infiltration, and decreased thickness of the vessels; group 3 animals exhibited decreased numbers of active fibroblasts and collagen fibers in the lamina propria.
  
  
  CONCLUSIONS
  Inflammation scores, cellular infiltration, and expression of VEGF, TGF-β, and iNOS were reduced by ascorbic acid and/or NAC treatments, thereby decreasing MS development. Decreased expression of IL1-β was observed only in animals treated with NAC.
authors.affiliation: Kızıltepe State Hospital, ENT Department, Mardin, Turkey.
authors.forename: Rıza
authors.initials: R
authors.lastname: Dündar
authors.affiliation: Celal Bayar University, Faculty of Medicine, Histology and Embryology Department, Manisa, Turkey.
authors.forename: Sevinç
authors.initials: S
authors.lastname: İnan
authors.affiliation: Kırıkkale University, Faculty of Medicine, ENT Department, Kırıkkale, Turkey. Electronic address: nbayarmuluk@yahoo.com.
authors.forename: Nuray Bayar
authors.initials: NB
authors.lastname: Muluk
authors.affiliation: Osmangazi University, Medical Faculty, Department of Otorhinolaryngology, Eskisehir, Turkey.
authors.forename: Cemal
authors.initials: C
authors.lastname: Cingi
authors.affiliation: Urla State Hospital, ENT Department, İzmir, Turkey.
authors.forename: Ali Ekber
authors.initials: AE
authors.lastname: İlknur
authors.affiliation: İzmir Katip Çelebi University, Training and Research Hospital, ENT Clinics, İzmir, Turkey.
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Katılmış
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology*; D004195:Disease Models, Animal; D005260:Female; D005339:Fibrin Foam; D005347:Fibroblasts / Q000378:metabolism; D016166:Free Radical Scavengers / Q000494:pharmacology; D006168:Guinea Pigs; D006490:Hemostatics; D007150:Immunohistochemistry; D007249:Inflammation / Q000473:pathology; D007962:Leukocytes / Q000378:metabolism; D008853:Microscopy; D009092:Mucous Membrane / Q000473:pathology; D063371:Myringosclerosis / Q000473:pathology / Q000517:prevention & control*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D011897:Random Allocation; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014432:Tympanic Membrane / Q000378:metabolism* / Q000473:pathology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005339:Fibrin Foam; D016166:Free Radical Scavengers; D006490:Hemostatics; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D019001:Nitric Oxide Synthase; D001205:Ascorbic Acid; D000111:Acetylcysteine
keywords: Ascorbic acid; Inducible nitric oxide synthase (iNOS); Interleukin 1-beta (IL1-β); Myringosclerosis; N-acetyl cysteine (NAC); Vascular endothelial growth factor (VEGF)