Study on the Potential Mechanism of Semen Strychni against Myasthenia Gravis Based on Network Pharmacology and Molecular Docking with Experimental Verification

Background. Semen Strychni (SS) is an effective Chinese medicine formula for treating myasthenia gravis (MG) in clinics. Nonetheless, its molecular mechanism is largely unknown. Objective. Using network pharmacology, molecular docking, and experimental validation, we aim to identify the therapeutic effect of SS on MG and its underlying mechanism. Methods. The main ingredients of SS and their targets and potential disease targets for MG were extracted from public databases. The protein-protein interaction (PPI) network was constructed using the STRING 11.0 database, and Cytoscape was used to identify the hub targets. In addition, Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to identify molecular biological processes and signaling pathways. Then, AutoDock Via conducted molecular docking. The experimental autoimmune myasthenia gravis (EAMG) model in female Lewis rats, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and enzyme-linked immunosorbent assay (ELISA) were performed to confirm the effect and mechanism of SS on MG. Results. The following active compounds and hub targets were identified by screening and analyzing: isobrucine, vomicine, (S)-stylopine, strychnine, brucine-N-oxide, brucine and AKT1, MAPK1, MAPK14, CHRM1, ACHE, and CHRNA4. KEGG enrichment analyses indicated that the cholinergic synapse and neuroactive ligand-receptor interaction signaling pathway may be necessary. The results of molecular docking revealed that the main active ingredients bind well to the hub targets. In vivo experiments proved that SS could improve the weight loss and Lennon scores in the EAMG model. Experiments in molecular biology showed that SS could treat MG by affecting the cholinergic synapse through the respective antibody, receptor, and key enzymes in the cholinergic pathway. Conclusion. This study provided a preliminary overview of the active constituents, primary targets, and potential pathways of SS against MG. SS ameliorated EAMG by regulating the cholinergic synaptic junction.