Influence of ozone and nitrogen dioxide on histamine and interleukin formation in a human nasal mucosa culture system

There is evidence that asthma and other allergic diseases are increasing an d air pollution has been considered an important contributing factor to thi s observation. Using a specially designed organ culture system, we examined the influence of ozone (0.06 to 0.2 ppm) and nitrogen dioxide (NO2, 200 an d 800 mu g/m(3)) on nasal mucosa exposed for 24 h. Tissue was obtained from 105 patients undergoing surgical therapy (septoplasty and reduction of the inferior turbinates) for chronic nasal obstruction. The histamine content in the culture medium of ozone- and NO2-exposed samples was significantly e levated compared with the control cultures. This elevation was correlated w ith the number of degranulated mast cells in the tissue determined by histo morphometry (P < 0.001). Moreover, the cytokines interleukin (IL)-1 beta (P < 0.05), IL-6 (P < 0.01), IL-8 (P < 0.001), and tumor necrosis factor-alph a (TNF-alpha, P < 0.001) were significantly increased (ozone 0.1 ppm). Furt hermore, we found significant increases in the release of IL-4, IL-6, IL-X, and TNF-alpha of ozone-exposed (0.1 ppm) samples of atopic versus nonatopi c patients and to a lesser extent for histamine following exposure to 0.15 ppm ozone. These results indicate that low ozone concentrations and NO2 lea d to an inflammation of human nasal mucosa in vitro and that priming factor s such as atopy or preexisting inflammation do increase the sensitivity to ozone and NO2. This organ culture system proved to be a good experimental d esign for studying pathophysiologic alterations of human nasal mucosa under different experimental conditions (e.g., air pollutants).