Study on the expression of interleukin-35 in serum of mice with pulmonary interstitial fibrosis

Objective To investigate the expression of interleukin-35 (IL-35) in serum of mice with pulmonary interstitial fibrosis. Methods Thirty-six C57BL/6 mice were divided into three groups (twelve mice in each group): control group, model group of mice with bleomycin-induced pulmonary fibrosis, glucocorticoid treatment group of mice with bleomycin-induced pulmonary fibrosis. The mice were sacrificed at day 7, day 14 and day 28 respectively, and the serum concentration of IL-35 was assayed. Statistical product and service solutions (SPSS) 17.0 statistical software was used for single factor analysis of variance and LSD-t comparison and Pearson correlation analysis was used for the comparison between each two groups. Results The serum IL-35 concentrations between groups and within groups at the time of day 7, day 14 and day 28 were compared respectively. The serum IL-35 concentration of the model group was significantly lower than the control group and the glucocorticoid treatment group at the time of day 7 (F=24.56, P 0.05). The serum IL-35 concentration of the model group at the time of day 28 was significantly higher than those of day 7 [(9.36±0.95) ng/ml vs (6.51±0.58) ng/ml, t=5.14, P<0.05], and which of glucocorticoid treatment group was significantly lower than those of day 7 [(5.27±1.01) ng/ml vs(9.42±0.84) ng/ml, t=6.32, P<0.05]. From day 7 to day 28 the serum IL-35 concentration change of the model group and glucocorticoid treatment group showed significantly negative correlation (r=-0.743, P<0.05) . Conclusion Serum IL-35 concentration has shown an trend of increase during bleomycin-induced pulmonary fibrosis with mice model, and early glucocorticoid treatment can decrease the serum IL-35 in the model mice. Key words: Pulmonary fibrosis; Interleukin-35