Abstract
BACKGROUND: Diabetes mellitus-induced erectile dysfunction (DMED) is a common complication of diabetes mellitus. Earthworm protein (EWP) is an active protein extracted from the Chinese herbal medicine earthworm, which is used in clinical practice for treating DMED. OBJECTIVE: To investigate the mechanism of action of EWP in improving DMED in rats using network pharmacology and in vivo experimental validation. MATERIALS AND METHODS: Network pharmacology predicts key targets. After identifying the DMED targets of EWP, a protein-protein interaction network was constructed using the STRING platform. The target genes were then enriched using Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes. A "drug-component-disease-target-pathway" network map with Cytoscape 3.9.1 software was constructed. The nuclear factor-kappa B (NF-κB) signaling pathway was selected for further in vivo experimental validation in rats. RESULTS: EWP was mainly involved in the inflammatory response and NF-κB signaling pathway to regulate DMED. In vivo experiments showed that EWP was able to reduce Interleukin-1β, Interleukin-6 and Tumour Necrosis Factor-α levels, significantly inhibit NF-κB, nuclear factor-κB inhibitor protein α and mRNA expression, increase serum testosterone (T), and improve the erectile function of DMED rats. CONCLUSION: EWP improves erectile function in DMED rats. This mechanism may be related to the inhibition of the NF-κB signaling pathway, reduction of the inflammatory response in testicular tissue, promotion of testicular and penile tissue repair, and increase in serum T levels.