Immunohistochemical localization of 3-nitrotyrosine in the nasal respiratory mucosa of patients with vasomotor rhinitis

CONCLUSION: This study demonstrates that, in the nasal respiratory mucosa of patients with vasomotor rhinitis, oxidative stress following peroxynitrite formation is confined to the respiratory epithelium. This suggests that the role of peroxynitrite in vasomotor rhinitis differs from its role in other diseases of the respiratory tract. The results of this study also support the concept that different pathogenetic mechanisms are probably involved in vasomotor rhinitis. OBJECTIVE: Previous studies indicated that nitric oxide (NO) is involved in the pathogenesis of vasomotor rhinitis, strong expression of NO synthase being detected in the smooth muscle cells of the cavernous sinuses and in the respiratory epithelium. However, most adverse effects of high levels of NO originate from the reaction of NO with superoxide anions to form peroxynitrite. Therefore, in this study we evaluated the involvement of peroxynitrite in the pathogenesis of vasomotor rhinitis. MATERIAL AND METHODS: Sites of peroxynitrite formation were identified by immunolabelling for 3-nitrotyrosine (3NT), its footprint in tissues. Samples of nasal mucosa were obtained from vasomotor rhinitis patients and from control subjects who had undergone corrective surgery of the nasal septum. All samples were obtained by reduction of the inferior turbinate. RESULTS: Examination of specimens from vasomotor rhinitis patients revealed that 3NT is absent in epithelium with a normal appearance, cells of the subepithelial connective tissue, the glands and the blood vessels, including the cavernous sinuses. In contrast, intense 3NT immunolabelling was found in the disrupted respiratory epithelium. 3NT was not present in any of the specimens from control subjects