Early and Late Effects of Capsaicin Pretreatment in Otitis Media with Effusion

Abstract

Discovery of the role of the neurogenic inflammation in the formation of otitis media with effusion has led to the investigation of the place of some neuropeptide antagonists in the treatment. In the current study, we investigated the effect of capsaicin (CP) pretreatment on the inflammation and proliferation in the middle ear mucosa and on the nerve fibers containing substance P, vasoactive intestinal polypeptide, and calcitonin gene-related peptide. Seventeen Wistar rats were used in the study. Ten rats were given CP on 3 consecutive days, and seven rats were given isotonic saline solution. Seven days after the third injection, animals were operated on, and their eustachian tubes were occluded. On the seventh day after the operation, five rats from the test group and three from the control group were killed. The others were killed 21 days after the operation. In the histopathologic examination of the sections, acute inflammation and proliferation scores were determined. Gland degeneration, goblet cell hyperplasia, and the density of mast cells were evaluated. Neural elements were stained immunohistochemically. The acute inflammation score in the test group was lower, but the difference was insignificant (p > 0.05). The proliferation score in the test group was lower, and the difference was significant (p = 0.02). In the control group, gland degeneration was significantly higher (p = 0.044). Goblet cell hyperplasia demonstrated no difference between two groups (p > 0.05). Mast cell density was higher in the control group, but the difference was not significant (p > 0.05). Substance P immunoreactivity (IR) was significantly higher in the control group (p = 0.015). calcitonin gene-related peptide-IR and vasoactive intestinal polypeptide-IR were limited in both groups. That CP pretreatment reduces inflammatory proliferative findings, and gland degeneration leads us to consider that it could be effective in both treatment of experimental otitis media with effusion and prevention of its complications.