Forsythiaside A ameliorates bleomycin-induced pulmonary fibrosis by inhibiting oxidative stress and apoptosis

Background: Pulmonary fibrosis (PF) is a common clinically critical disease characterized by high morbidity and high mortality. Forsythiaside A (FA) is a phenylethanol glycoside component in Forsythia suspensa, which has anti-inflammatory, antioxidant, and antiviral activities. However, the effects of FA on bleomycin (BLM)-induced PF are unclear. Purpose: The present study explored the role of FA in the amelioration of oxidative stress and apoptosis in BLM-induced PF as well as the possible underlying mechanisms, in vivo and in vitro. Methods: Network pharmacology was used to collect the effects of FA on BLM-induced PF. Subsequently, further observation of the effects of FA on mice with PF by pulmonary pathological changes, transmission electron microscopy, real-time polymerase chain reaction, Western blot analysis, immunofluorescence, and immunohistochemistry. An in vitro model was constructed by inducing A549 with transforming growth factor beta-1 (TGF-beta 1) to observe the effect of FA on epithelial cell apoptosis. Results: Network pharmacology predicted signaling pathways such as IL-17 signaling pathway and Relaxin signaling pathway. The results of in vivo studies showed that FA ameliorated BLM-induced PF through inhibition of fibrosis, modulation of apoptosis, and oxidative stress. In addition, FA promoted TGF-beta 1-induced apoptosis in A549 cells. Conclusions: The results of our study suggested that FA could protect mice against BLM-induced PF by regulating oxidative stress and apoptosis as well as the Epithelial mesenchymal transition pathway.