A study of free lung cells from young rats chronically exposed to carbon monoxide from birth.

Carbon monoxide (CO) is a well know constituent of cigarette smoke and automobile exhaust. The purpose of this study was to determine the effect of CO on the first line of lung defense, the alveolar macrophage (AM). Free lung cells were obtained by bronchoalveolar lavage with Dulbecco's phosphate buffered saline from rats exposed to 500 ppm CO from birth until 33 days of age and from littermate controls. Morphological and functional parameters of the exposed cells showed minor changes. Hemoglobin concentration and hematocrit were significantly elevated in the CO-exposed group. Recovery yield of lavage fluid, wet lung weight, and lung displaced volume were identical to controls. Neither number of AM, viability, maximal diameter, surface area nor acid phosphatase activity of exposed AM appeared to be different from controls. However, in a test with fluorescent latex spheres, the phagocytic ability of AM was found to be enhanced in CO-exposed rats and was correlated with an increased percentage of spread forms of AM adhering to glass coverslips. The surface features of the AM were somewhat modified. Number and percentage of granular leukocytes were statistically increased in lavages following chronic exposure to CO. These alterations contrast with the effects of diesel exhaust and cigarette smoke.