Objective The present study was undertaken to examine the regulatory effect of endogeous sulfur dioxide (SO2) on interleukins in rats with acute lung injury (ALI) induced by sepsis.Methods Twenty Two male Sprague Dawley (SD) rats were randomly (random number) divided into sham group (Control group),sham + SO2 donor (Na2SO3/NaHSO3,0.54 mmol/kg:0.18 mmol/kg) group (SO2 group),sepsis induced ALI group (sepsis group) and sepsis induced ALI with sulfur dioxide pretreatment group (sepsis + SO2 group).Index of quantitative assessment of histological lung injury (IQA),wet/dry weight ratio (W/D) and the level of SO2 in plasma were measured.IL 6,IL 8,IL 10,MCP-1 and TNF-α were measured by ELISA.Results The IQA score and W/D ratio of lung tissues significantly increased in sepsis rats compared with control group (all P ＜ 0.01),but significantly decreased in sulfur dioxide pretreatment rats compared with in sepsis rats (all P ＜0.01).The level of SO2 in plasma decreased in sepsis rats (3.17 ± 3.44) μmol/L compared with control group (5.87 ± 1.96) μmol/L,but significantly increased in sulfur dioxide pretreatment rats (9.78 ± 3.26) μmol/L compared with in sepsis rats (P ＜0.01).The level of IL 6,IL 8,IL 10,MCP-1 and TNF-α significantly increased in sepsis rats [(87.08 ± 22.03) pg/mg,(79.82 ± 19.69) pg/mg,(66.38 ± 21.77) pg/mg,(157.58 ± 42.36) pg/mg and (65.04 ± 19.42) pg/mg,respectively] compared with control group [(47.41±9.64) pg/mg,(42.25±8.16) pg/mg,(31.96±4.63) pg/mg,(67.65±10.18) pg/mg and (33.83 ± 5.75) pg/mg] (all P ＜ 0.01).but the level of IL 6,IL 8,IL 10 significantly decreased in sulfur dioxide pretreatment rats [(66.01 ± 16.52) pg/mg,(61.52 ± 18.32) pg/mg and (45.61 ± 16.47) pg/mg,respectively] compared with sepsis group (all P ＜ 0.05).The level of MCP-1 significantly decreased in sulfur dioxide pretreatment rats (117.86 ± 34.20) pg/mgcompared with sepsis group (all P ＜0.01).The level of TNF-α decreased in sulfur dioxide pretreatment rats (61.49 ± 15.33 pg/mg) compared with sepsis group.Conclusions These results suggested that exogenous SO2 could inhibit the pulmonary tissue inflammatory response by inhibiting MCP-1 and TNF-α in rats with sepsis induced ALI.