RESUMO
OBJECTIVE: In the present study, tympanic membranes (TM) harvested from myringotomized rats were analyzed histopathologically to compare the systemic and local effects of ascorbic acid on the development of myringosclerosis. MATERIALS AND METHODS: Forty male Wistar-Albino rats weighing between 350-400 g were included in this study. Under otomicroscopic examination, a standard 2-mm myringotomy incision was made on the posteroinferior quadrant of the TM of both ears. Rats were randomized into five groups as control, topical ascorbic acid 50 mg/kg, systemic ascorbic acid 50, 100, and 200 mg/kg groups, each group containing eight rats. On the 15th day of the study, the rats were decapitated, and bullas of the rats were extracted. Sections were stained with hematoxylin-eosin and examined through light microscopy. Inflammation, distribution width of plaques, edema, and neovascularization were observed on the lamina propria. Thickness of the TM was evaluated under the microscope and scored semiquantitatively. RESULTS: When intergroup comparisons of parameters related to total TM thickness were performed, differences between the control group and topical AA (ascorbic acid) or systemic treatment groups were found to be statistically significant (p<0.005). A statistically significant difference was detected among control, topical and systemic 200 mg/kg ascorbic acid groups for the edematous lamina propria (p=0.003 and p<0.05, respectively). CONCLUSION: For the total TM thickness, systemic and topical ascorbic acid use was effective when compared with the control group. It has been concluded that systemic use of higher doses of (200 mg/kg) ascorbic acid is beneficial in the resolution of the edematous lamina propria.
