Effect of Sulfur Dioxide Inhalation on Cytokine Levels in Lungs and Serum of Mice

Abstract

In order to elucidate the immunotoxic mechanism exerted by sulfur dioxide (SO₂), we investigated the effect of SO₂, a major air pollutant, on the cytokine levels in lungs and serum of male mice. Levels of interlukin-6(IL-6), tumor necrosis factor-α (TNF-α), and transforming growth factor-β1 (TGF-β1) in lungs and serum from male mice exposed to SO₂ at various concentrations were measured by the enzyme-linked immunosorbent assay. Sixty Kunming albino male mice were divided randomly into six equal groups: three groups exposed to SO₂ (14.00 ± 1.25, 28.00 ± 1.98, and 56.00 ± 3.11 mg/m³, which are 5 ± 0.45, 10 ± 0.71, and 20 ± 1.11 ppm) and their respective control groups. The results were as follows: (1) For lung tissues of male mice, exposure to SO₂ at 14 mg/m³ (5 ppm) caused statistically significant increase of levels of IL-6 and TNF-α (p < .05) compared with the control group; exposure at 28 mg/m³ (10 ppm) caused a statistically highly significant increase of level of IL-6 (p < .01) and a significant increase of TNF-α (p < .05); and exposure at 56 mg/m³ (20 ppm) caused no any significant increase of levels of IL-6 and TNF-α. SO₂ at all concentrations tested could not cause significant change of level of TGF-β1 in lungs. (2) For serum from male mice, after exposure to SO₂ at 14 mg/m³ (5 ppm), the level of TNF-α was significantly increased (p < .05) compared with the control group, but the changes of levels of IL-6 and TGF-β1 were not significant. After exposure to SO₂ at 28 mg/m³ (10 ppm) and 56 mg/m³ (20 ppm), levels of IL-6 and TNF-α were increased nonsignificantly, but the level of TGF-β1 was decreased nonsignificantly. These results imply that inflammation reaction could be induced in lung tissue by SO₂ inhalation and the inflammation reaction might relate to these cytokines. And determination of cytokines in lung may be more valuable than in serum when lung injury caused by SO₂.