Effect of Shenlong Jianji in the Treatment of Idiopathic Pulmonary Fibrosis: Assessment of Pharmacological Mechanism and Animal Experimental Verification

Background: Nowadays, non-effective drugs have been confirmed for idiopathic pulmonary fibrosis (IPF) therapy. Previous experimental studies have shown that Shenlong Jianji (SLJJ) is a potentially effective Chinese herbal formula for IPF therapy. However, more research is needed to assess its therapeutic targets and intervention mechanisms.Methods: Active ingredients, corresponding targets of active ingredients and disease targets were assessed. Based on interrelation between active ingredient targets and disease targets, gene enrichment analyses were performed to assess the potential pharmacological mechanism of SLJJ for IPF. Overall, 144 Wistar adult rats were randomly divided into six groups (control group, model group, prednisone group and SLJJ high, medium, and low doses groups). Rats were given bleomycin (BLM) to trigger IPF. After treatment with corresponding medicine, histopathology changes of lung tissue were assessed using hematoxylineosin staining and masson's trichrome staining. Concentration of hydroxyproline (HYP) in lung tissue was analyzed using chloramine hydrolysis method. Lung function and blood gas analysis of rats in each group were also assessed in this study. Interferon --y (IFN--y) and Interleukin-4 (IL-4) content in serum were assessed using enzyme-linked immunosorbent assay. Protein and gene expressions of IFN--y, IL-4, transforming growth factor -01 (TGF-01), transforming growth factor-0RII (TGF-0RII), Smad3, and Smad7 in lung tissue were assayed using western blotting and realtimepolymerase chain reaction.Results: 126 signaling pathways were obtained by gene enrichment analysis. Overall, SLJJ groups showed significant improvement on histopathology assessment and reduced HYP content in lung tissue compared to model group. SLJJ can also improve lung function and blood gas analysis results. Additionally, there was a decrease on IL-4 level and increase on IFN--y level in serum, down-regulating IL-4, TGF-01, TGF-0RII, Smad3 protein and mRNA expressions and up-regulating IFN--y and Smad7 protein and mRNA expressions in lung tissue.Conclusions: Our findings suggest that SLJJ is a valid formula to alleviate BLM-induced IPF, while its partial mechanism might mediate by coordinating the IFN--y/IL-4 balance and regulating the TGF-01/Smads signaling pathways. The potential targets predicted by network pharmacology warrant further validation.