OBJECTIVETo observe the effect of sulphur dioxide (SO2) inhalation on the pathogenesis of allergic rhinitis (AR) in mice, and investigate the toxic effect of SO2 on respiratory tract mucosa.

METHODSFifty male Kunming strain mice were randomly allocated to five groups, i. e., control group, AR group and AR plus different concentrations of SO2 group (three sub-groups). Nasal cavity irrigating solution was gathered from nasal cavity, and blood from the orbital venous sinus after anesthesia The concentrations of IL-5 and IL-13 in the peripheral serum and nasal cavity irrigating solution were measured by ELISA. The number of eosinophils (EOS) per square millimeter in sinus mucosa was calculated by hematoxylin-eosin. The expression of SP-D in nasal mucosa was analyzed by immunohistochemistry technique.

RESULTSWith increasing concentrations of SO2, the levels of IL-5 and IL-13 in the peripheral serum, and the density of Eos in sinus mucosa increased simultaneously. A positive correlation existed between the concentration of inhaled SO2 and the elevation of both IL-5, IL-13 and Eos infiltration in nasal mucosa. The coefficient correlation relatively were 0.894, 0.874, 0.894, 0.891 and 0.870 (P <0.01). The expression of SP-D in 56 mg/m3 and 112 mg/m3 SO2 groups was higher, while it was lower in 168 mg/m3 SO2 group (P < 0. 001).

CONCLUSIONSThe study showed that sulphur dioxide inhalation facilitates the onset of allergic rhinitis in mice. SO2-related Th2-derived cytokines as well as the infiltration of EOS in nasal mucosa help to aggravate the development of allergic rhinitis.