Cytological damage of nasal epithelium associated with decreased glutathione peroxidase in residents from a heavily polluted city

Objective: To evaluate the cytological damage and glutathione peroxidase (GPX) content in the nasal epithelium of residents of Southwest Metropolitan Mexico City (SWMMC) along 1 year of ozone and PM₁₀ exposure. Method: Four nasal scrapings were obtained in 20 volunteers from a control low polluted city and SWMMC permanent residents (n = 20) during 1 year. The scrapings were obtained in September and December 2004, and February and May 2005. One part of the scraping was stained by hematoxylin-eosin technique for cytological evaluation and a second part was stained by immunocytochemistry method to evaluate GPX concentration by morphometry. Results: Control subjects: in total, 30% had no cytological alterations and 70% showed only mild or moderate inflammation in four nasal scrapings. All SWMMC residents showed moderate to severe inflammatory processes in some scrapings. Additionally, dysplasia was found once (in 2 cases) or more than on scraping in five cases (25%). GPX concentration in the control group remained highest in median values throughout the study. SWMMC residents with the highest median values of GPX content were found in the May and September scrapings, and the lowest median values were found in December and February when Ozone and PM₁₀ levels are increased (P ≤ 0.05). A lower GPX content was found as the cytological damage increased (P ≤ 0.001). Conclusion: Cytological evaluation of nasal epithelium and GPX immunodetection are satisfactory methods to evaluate the earliest damage produced by atmospheric pollution in heavily contaminated cities.