Role of free radicals and antioxidants in nasal polyps.

OBJECTIVES/HYPOTHESIS The aim of this study is to determine the role of free radicals and antioxidants in nasal polyps. STUDY DESIGN Prospective, randomized, controlled study. METHODS Thirty-one patients with nasal polyposis and a control group consisting of 19 patients with septal deviation and lower turbinate hypertrophy were included in the study. Levels of the antioxidants retinol, beta-carotene, alpha-tocopherol, and ascorbic acid were measured from the sera of the patients with nasal polyposis and the control group. Plasma levels of superoxide dismutase activity (SOD), glutathione peroxidase (GSHPX) activity, and reduced glutathione (GSH) were also obtained. As a peroxidation product, the levels of the malondialdehyde-thiobarbituric acid (MDA) combination were measured from the plasma of patient and control groups. Measurements of MDA, GSH, and alpha-tocopherol levels were also taken from the polyp tissue and turbinate mucosa of the control group. RESULTS The blood levels of antioxidants and MDA as an oxidant were significantly different in the patient group compared with the control group (P <.01). The tissue levels of antioxidants and MDA were significantly different in the patients with polyposis compared with the control group (P <.01). The blood and tissue anti-oxidant levels were found to be decreased, and MDA levels as an oxidant increased significantly in the patient group with polyposis when compared with the control group, and there was a negative correlation between oxidative stress and antioxidants. CONCLUSION This study demonstrates that oxidative stress and tissue and blood antioxidants in the patients with polyposis were significantly different compared with the control group. The blood and tissue antioxidant levels decreased, and MDA levels, as an oxidant, increased significantly in the patient group with polyposis when compared with the control group. The current study demonstrates that there is strong evidence related to oxidative stress in the pathogenesis of nasal polyposis, and antioxidants can have a preventive role in free-radical-mediated tissue damage in nasal polyposis.