The Effect Of IL-27 Regulating TGF-β/Smad And JAK/STAT Signaling Pathway In The Bleomycin-induced Pulmonary Fibrosis

Objectives:To explore the effect of Interleukin-27 (IL-27) regulating TGF-β/Smad and JAK/STAT signaling pathway in the bleomycin-induced pulmonary fibrosis, we observed the expression of signaling pathway-related proteins in the bleomycin-mice lung tissue and after giving IL-27 and IL-27 antibody treatment.Methods:1. All the C57/BL6 male mice with age of 6-8 weeks and total number of 40 are randomly divided into four groups. Group A is control group. Group B is bleomycin-induced group. Group C is bleomycin-induced with the treatment of IL-27 group. Group D is bleomycin-induced with the treatment of IL-27 antibody group. Each group has 10 mice.2. All the mice in Group A are injected saline solution through trachea. All the mice in the other Group are injected saline solution with bleomycin in order to produce the pulmonary fibrosis model. All the mice in Group C were treated with IL-27 recombinant protein 1μg/day for 7 days from the day after modeling using abdominal subcutaneous injection. All the mice in Group D are injected with a single dose of IL-27 antibody for each mouse at the same time with modeling.3. The 7th day and the 28th day after modeling, we killed 5 mice in each group, the left lung tissue was observed with pathology technique.4. The expression of TGF-βR1, Smad1, Smad3, JAK2, STAT1, STAT3, STATS and SOCS3 proteins in the right lung tissue were assessed by Western blot analysis.Results:1. The pathological result indicated:The 7th day after modeling, the severity of alveolitis in Group D is the most serious, Group B is secondary, and Group C is less than Group B. While there is non-performance of alveolitis found in Group A. The 28th day, the severity of pulmonary fibrosis in Group D is the most serious, Group B is secondary, and Group C is less than Group B. While there is non-performance of pulmonary fibrosis found in Group A.2. Compare with Group A, the expression of TGF-βR1, p-Smad1 and p-Smad3 proteins in Group B,C,D were increased in the 7th day and the 28th day, and Group D has the highest expression. Those proteins expression in Group C is less than Group B in the 7th day.3. Compare with group A, the expression of p-JAK2, p-STAT1, p-STAT3 and p-STAT5 proteins in Group B, C, D were increased in the 7th day and the 28th day, and Group D has the highest expression. Those proteins expression in Group C is less than Group B in the 7th day. The 7th day and the 28th day, the expression of SOCS3 protein were reduced in group B, C, D, and group D has the least expression and the amount of SOCS3 protein in Group C is more than Group B.Conclusions:1.TGF-β/Smad and JAK/STAT signaling pathway (The increasing phosphorylation of signal pathway-related proteins such as TGF-βR1, Smadl, Smad3, JAk2, STAT1, STAT3 and STAT5) in the bleomycin-mice lung tissue were activated, which are involved in the process of pulmonary fibrosis.2. The exogenous IL-27 may alleviate the severity of pulmonary fibrosis through inhibiting the activation of TGF-β/Smad and JAK/STAT signaling pathway.3. Giving IL-27 antibody may neutralize the inhibiting effect of endogenous IL-27 regulate the activation of TGF-β/Smad and JAK/STAT signaling pathway to aggravate pulmonary fibrosis in the bleomycin-mice lung tissue.