Oxysophocarpine Inhibits Apoptosis of Lung Epithelial Cells to Alleviate Acute Lung Injury via KIT/PI3K Signaling Pathway.

Purpose: Acute lung injury (ALI) is an acute, diffuse, inflammatory lung injury caused by many factors. Oxysophocarpine (OSC), a quinoline alkaloid sourced from traditional Chinese herbs Sophora flavescens and Sophora davidii, possesses anti-inflammatory and antioxidant properties. However, its effects on ALI are still unclear. This study aims to investigate the role and potential mechanisms of OSC for the treatment of ALI.

Methods: The levels of TNF-α, IL-6, and IL-1β in bronchoalveolar lavage fluid (BALF) were measured with an enzyme-linked immunosorbent assay (ELISA). Lung tissue changes were examined through hematoxylin and eosin (HE) staining. Lung cell apoptosis was analyzed using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Flow cytometry was utilized to detect neutrophil aggregation. Further, the network pharmacology and molecular docking was employed to predict the mechanisms. Key pathways and targets of OSC were confirmed using methods like immunohistochemistry (IHC), immunofluorescence (IF), real-time quantitative PCR (RT-qPCR), and Western blotting (WB).

Results: In vivo, OSC treatment significantly inhibited diffuse alveolar injury and interstitial edema compared to the LPS-induced model mice, reduced neutrophil infiltration, and lowered lung epithelial cell apoptosis. In vitro, OSC pretreatment enhanced lung epithelial cell viability and decreased LPS-induced apoptosis. Network pharmacology analysis suggested that OSC mainly targeted key proteins in the PI3K/AKT and apoptosis signaling pathways, such as KIT, PIK3CA, and Bcl-2. Molecular docking confirmed that OSC binds strongly to these targets. Further, PCR, WB, IF, and IHC assay demonstrated that OSC pretreatment elevated PI3K, KIT, and Bcl-2 expressions in BEAS-2B lung epithelial cells and lung tissues.

Conclusion: OSC reduced inflammatory cytokine production, neutrophil aggregation, and lung epithelial cell apoptosis via regulating the KIT/PI3K signaling pathway.