To compare the effects of interleukin (IL)-27 and N-acetylcysteine (NAC) on bleomycin-induced pulmonary fibrosis in mice.

Mice models were established by endobronchial injection of bleomycin (BLM). The normal healthy mice were taken as group A, the mice receiving only endobronchial injection of BLM were taken as group B, the mice receiving endobronchial injection of BLM+ IL-27 were taken as group C, and the mice receiving endobronchial injection of BLM+ NAC were taken as group D. Every 5 mice were executed in each group respectively at 7, 14, and 28 days after treatment. Then HE staining and Masson staining were performed on the lung tissues, and alveolitis scoring, pulmonary fibrosis scoring, and hydroxyproline content determination of the lung tissues were made and compared.

The 7-day alveolitis scores were (1.00±0.00) in group A, (3.47±0.23) in group B, (2.17±0.13) in group C, and (2.89±0.29) in group D. The 14-day alveolitis scores were (1.00±0.00) in group A, (2.94±0.31) in group B, (1.92±0.16) in group C, and (2.48±0.19) group D. And the 28-day alveolitis scores were (1.00±0.00) group A, (1.97±0.19) in group B, (1.38±0.18) in group C, and (1.65±0.17) in group D. The 7-day pulmonary fibrosis scores were (1.00±0.00) in group A, (1.82±0.22) in group B, (1.21±0.13) in group C, and (1.51±0.26) in group D. The 14-day pulmonary fibrosis scores were (1.00±0.00) in group A, (2.64±0.32) in group B, (1.95±0.15) in group C, and (2.13±0.16) in group D. And the 28-day pulmonary fibrosis scores were (1.00±0.00) in group A, (3.48±0.14) in group B, (2.17±0.17) in group C, and (2.96±0.18) in group D. The 7-day lung tissue hydroxyproline contents were (143.19±4.09) in group A, (281.83±8.31) in group B, (207.81±5.29) in group C, and (231.49±3.97) in group D. The 14-day lung tissue hydroxyproline contents were (147.81±8.91) in group A, (317.63±6.30) in group B, (253.86±4.91) in group C, and (289.73±5.09) in group D. And 28-day lung tissue hydroxyproline contents were (141.82±7.28) in group A, (381.97±5.49) in group B, (303.81±4.92) in group C, and (358.29±7.38) in group D. The differences among the groups were statistically significant.

NAC and IL-27 have inhibitory effects on the bleomycin-induced pulmonary fibrosis in mice. However, the alveolitis scores, pulmonary fibrosis scores and hydroxyproline contents in the IL-27 intervention groups were lower than those in the NAC intervention group. Therefore, IL-27 is superior to NAC in inhibiting pulmonary fibrosis.