PURPOSE and METHODS: Although many reports have been described a direct relation between reactive oxygen species (ROS) and nitric oxide (NO) and several disorders, the relationship between ROS/NO and epistaxis remains unclear. In this study, differences in the mRNA expression of Mn-SOD, CuZn-SOD, Catalase, iNOS, eNOS, COX-I, COX-II and p22phox (a subunit of NADPH oxidase) were studied in the epithelium of the nasal mucosa in patients with epistaxis (n=28) and healthy subjects (n=24).
RESULTS: The expression of Mn-SOD, CuZn-SOD and catalase was significantly higher in the epistaxis group than in the healthy group. This finding suggests that O
2- is related to epistaxis and that these mRNAs were expressed as part of a protective reaction against oxidative stress. The expression of iNOS, COX-I and COX-II was also significantly higher in the epistaxis group. The expression of iNOS produces NO, and NO activates COX-I and COX-II to produce more free radicals. In addition, p22phox expression in the epistaxis group was stronger than in the healthy group, indicating that NADPH oxidase may also cause epistaxis through the production of O
2-.
CONCLUSION: We demonstrated that ROS produced by COX-I, COX-II and NADPH oxidase and NO produced by iNOS may be involved in pathogenesis of epistaxis and that a protective reaciton involving SOD and catalase may be active.
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