Uncovering the molecular mechanisms of Salidroside against diabetic retinopathy using network pharmacology and experimental validation

Abstract Objective The present study was designed to explore the mechanism underlying the therapeutic effects of Salidroside in the treatment of diabetic retinopathy (DR) through network pharmacology analysis combined with in vivo experimental verification. Methods Diabetic rat models were established and treated with Salidroside. Optical coherence tomography (OCT) was employed to demonstrate the changes of retina with treatment or not. The drug targets of SAL and disease targets of DR were obtained from public databases. Venn diagrams were generated online to obtain the common targets of SAL and DR, which were then imported into String for protein-protein interaction (PPI) network generation Meanwhile, these common targets were analyzed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis to further elucidate their biological functions. Finally, gene-pathway networks were established to capture core pathways that common targets were enriched in. Molecular docking predicts the binding degree between drugs and proteins, and the expression levels of key genes are verified by real-time quantitative polymerase chain reaction (RT-qPCR) in vivo. Results OCT imaging demonstrated that Salidroside administration significantly increased retinal thickness and significantly reduce the number of new blood vessels in fundus images in diabetic rats. We obtained 87 common targets after intersecting the targets of Salidroside and DR, and PPI network screened out 7 core targets, including GAPDH, CASP3, VEGFA, HRAS, HIF1A, MTOR and MMP9. The functional annotation of target genes demonstrated they were enriched in such biological processes as cellular response to oxidative stress, epithelial cell proliferation, and response to reactive oxygen species, along with significantly enriched pathways like HIF-1 signaling pathway, AGE-RAGE signaling pathway in diabetic complications, Type II diabetes mellitus, and VEGF signaling pathway. Molecular docking prediction results indicated that Salidroside was stably bound to these core targets. Importantly, mRNA levels of core targets in diabetic rats were differentially expressed before and after Salidroside treatment. Conclusions Collectively, our work demonstrated Salidroside could protect the retina from diabetes-induced damage, and preliminarily uncovered that Salidroside might exert therapeutic efficacy in DR through a multi-target and multi-pathway approach.