Alveolar macrophages located on the alveolar surface have contact with air pollutants. We evaluated the dose-dependent effect of nitrogen dioxide exposure on the oxidative metabolism of alveolar macrophages and peripheral blood mononuclear cells by measuring the spontaneous and stimulated reactive oxygen intermediates production. Alveolar macrophages or peripheral blood mononuclear cells were placed on a polycarbonate membrane, which was in direct contact with the surface of a nutrient reservoir. The cells were exposed to nitrogen dioxide during different periods of time, varying between 30 and 120 min at concentrations ranging from 0.1 to 0.5 ppm. Exposure of alveolar macrophages to nitrogen dioxide for 30 min yielded a dose-dependent stimulation of reactive oxygen intermediates generation of 1.7- to 2.9-fold of control. An 120-min exposure to nitrogen dioxide at concentrations between 0.1 and 0.5 ppm resulted in a similar reactive oxygen intermediates production of about 1.9- to 2.2-fold of control at all concentrations tested. The nitrogen dioxide exposure to peripheral blood mononuclear cells yielded identical results. These experiments demonstrate that alveolar macrophages and peripheral blood mononuclear cells become activated by nitrogen dioxide and that concentrations up to 0.5 ppm nitrogen dioxide induce an increase in reactive oxygen intermediates production after 30 to 120 min exposure of the cells.

Aged↗

PubMedDate not supplied

Effect of sulfur dioxide on cytokine production of human alveolar macrophages in vitro.

Tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and transforming growth factor-beta are cytokines synthesized by alveolar macrophages. We investigated the effect of sulfur dioxide, a major air pollutant, on the production of these cytokines by alveolar macrophages. The cells were layered on a polycarbonate membrane and exposed for 30 min to 0.0, 1.0, 2.5, and 5.0 ppm sulfur dioxide at 37 degrees C and 100% air humidity. The cells were incubated for 24 h after exposure, thus allowing cytokine release. Cytotoxic effects of sulfur dioxide were evaluated by trypan blue exclusion. Cytokines were measured with enzyme-linked immunosorbent assays (i.e., tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6) or by use of a specific bioassay (i.e., transforming growth factor-beta). The toxicity of sulfur dioxide for alveolar macrophages ranged from 3.1 % to 9.5 %. A 30-min exposure to sulfur dioxide induced a significant decrease in spontaneous and lipopolysaccharide-stimulated tumor necrosis factor-alpha (p < .001) and lipopolysaccharide-stimulated interleukin-1beta release (p < .05). The release of interleukin-6 and transforming growth factor-beta was not affected significantly by sulfur dioxide exposure. Our results demonstrated a functional impairment of alveolar macrophages after sulfur dioxide exposure (i.e., release of tumor necrosis factor-alpha and interleukin-1beta). Neither spontaneous nor stimulated release of interleukin-6 and transforming growth factors were influenced by exposure to sulfur dioxide.

Air Pollutants↗

PubMedDate not supplied

Relationship between R t and FEV 1.0 before and after inhalation of isoproterenol in patients with chronic obstructive syndrome.

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Adult↗