Rıza Dündar1, Sevinç İnan2, Nuray Bayar Muluk3, Cemal Cingi4, Ali Ekber İlknur5, Hüseyin Katılmış6. 1. Kızıltepe State Hospital, ENT Department, Mardin, Turkey. 2. Celal Bayar University, Faculty of Medicine, Histology and Embryology Department, Manisa, Turkey. 3. Kırıkkale University, Faculty of Medicine, ENT Department, Kırıkkale, Turkey. Electronic address: nbayarmuluk@yahoo.com. 4. Osmangazi University, Medical Faculty, Department of Otorhinolaryngology, Eskisehir, Turkey. 5. Urla State Hospital, ENT Department, İzmir, Turkey. 6. İzmir Katip Çelebi University, Training and Research Hospital, ENT Clinics, İzmir, Turkey.
Abstract
OBJECTIVES: 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.
OBJECTIVES: 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.