Effects of Multiple Day Exposure to Nitrogen Dioxide on Human Cellular Immunity:211 Human Macrophage Responses

摘要

Fifteen healthy volunteers were recruited, provided informed consent and were211u001echaracterized with respect to pulmonary function, airway resistance and non-211u001especific airway reactivity. The subjects were exposed to filtered air (FA) or 2.0 211u001eppm nitrogen dioxide (NO2) for 4-hr per day, alternating 30-minute periods of 211u001erest and exercise, for 3 consecutive days. Bronchoscopy and bronchoalveolar 211u001elavage were performed 18-hr after the 3rd day of either FA or NO2 exposure. 211u001eMacrophages were recovered from the bronchoalveolar lavage fluid and selected 211u001emacrophage functions were assayed. Assays were performed for superoxide free 211u001eradical production by the macrophages before and after stimulation with phorbol 211u001emyristate acetate (PMA) and before and after simulation with serum-incubated 211u001eyeast particles (opsonized zymosan). This function, known as respiratory burst 211u001eactivity, is an important part of lung defenses against infectious agents. 211u001eHowever, excessive free radical production can overwhelm tissue defenses and 211u001ecause injury.