Objective   To investigate the effect of sulfur dioxide inhalation on levels of pro-and anti-inflammatory cytokines in lungs and serum of mice and further to elucidate an immunotoxic mechanism of SO₂.

  Methods   Levels of interlukin-6(IL-6), tumor necrosis factor-α(TNF-α), transforming growth factor-β1(TGF-β1)were measured by the enzyme-linked immunosorbent assay.

  Results   (1) For lung tissues, exposure to SO₂ at 14 mg/m³ caused statistically significant increase of IL-6 and TNF-α levels(P < 0.05), at 28 mg/m³ caused statistically highly significant increase of IL-6 levels (P < 0.01)and significant increase of TNF-α(P < 0.05), at 56 mg/m³ caused no any increase of IL-6 and TNF-α levels.SO₂ at all concentrations tested could not cause significant changes of TGF-β1 in lung.(2)For serum, SO₂ at all concentrations tested could not cause significant changes of IL-6, TNF-α and TGF-β1 levels, except TNF-α at 14 mg/m³ of SO₂.

  Conclusion   (1) The levels of pro-inflammatory cytokines in lungs were increased in a dose-dependent manner after exposure to SO₂, but anti-inflammatory cytokine had no significant difference.(2)In serum, levels of the three cytokines had no significant differences between SO₂ exposure and control groups, except TNF-α at 14 mg/m³ of SO₂.These results implied 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 was caused by SO₂.