Histopathological effects of intratympanic steroids in mi̇ddle ear mucosa : An ani̇mal study

ABSTRACT HISTOPATHOLOGICAL EFFECTS OF İNTRATYMPANİC STEROİDS İN MİDDLE EAR MUCOSA: AN ANİMAL STUDY Objective: The aim of this study is to assess and compare the histopathological effects of intratympanically applied dexamethazone and methylprednisolone, with untreated sample groups in an animal study model. Plan:Prospective, single blind,animal study Method: Thirty Sprauge Dawley rats were enrolled in the study. Animal split into two groups which one group left ears received intratympanic dexamethasone (n:15) and right ears received intratympanic saline solution (n:15), and other group received intratympanic methylprednisolone on their left ears .Right ears of the methylprednisolone group had no injections to serve as untreated controls(n:15). Animals received daily intratympanic injections for 10 days. At the 10th day 8 animals from each group sacrificed and dissected blindly. Middle ear mucosae of these animals were assessed for mucosal thickening, hematoma, hyperemia, adhesion, and tympanic membrane status, with a microscope. Then samples were taken from the mucosae and sent to pathology. Specimens dyed with hematoxylin and eosin and assessed for inflammatory cell infiltration and presence of fibroblasts, collagen, and vascularization. After the 30th day rest of the animals sacrificed and gone similar assessments. Results: 28 of the 30 rats were able to be enrolled in the study . two of the rats that receive intratympanic dexamethasone and intratympanic saline solution died . No meaningful statistical difference observed between dexamethasone, saline and control groups. . No meaningful statistical difference observed between methylprednisolone, saline and control groups except fibroblast presence (p=0,007). No statistical meaningful difference observed when comparing 10th and 30th day results. Conclusion: intratympanic dexamethasone and methylprednisolone applications don't produce irritating, pro-inflammatory effects on middle ear mucosa. Long term effects of these medications are also safe for middle ear mucosa. Even though results for dexamethasone are consistent with the literature, no previous studied could be found on methylprednisolone. Key words: intratympanic dexamethasone, intratympanic methylprednisolone, middle ear mucosa, sudden hearing loss, rat ear anatomy, histology