[Loganin alleviates oxidative stress and promotes osteoblast differentiation by inhibiting JAK2/STAT3 pathway]

This study aimed to investigate the effects of loganin on the osteogenic differentiation of mouse embryonic osteoblast precursor cells(MC3T3-E1) under oxidative stress and to explore its underlying mechanisms. First, a network pharmacology approach was employed to identify common targets of loganin and osteoporosis(OP) using SwissTargetPrediction, OMM, and GeneCards databases. A total of 31 potential targets were identified, with signal transducer and activator of transcription 3(STAT3), interleukin-2(IL-2), matrix metalloproteinase-9(MMP-9), and caspase-3 being central in the protein-protein interaction(PPI) network. Further enrichment analysis based on Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) suggested that the JAK-STAT signaling pathway might be a key pathway through which loganin exerts its effects. In vitro experiments utilized hydrogen peroxide(H_2O_2, 200 μmol·L~(-1)) to establish an oxidative stress injury model in MC3T3-E1 cells. The cells were divided into a control group, an H_2O_2 model group, and low-, medium-, and high-dose(50, 100, 200 μmol·L~(-1)) loganin groups. The results showed that loganin significantly reversed the H_2O_2-induced decreases in cell viability, reduced intracellular reactive oxygen species(ROS) levels, enhanced alkaline phosphatase(ALP) activity, and inhibited apoptosis. Western blot analysis revealed that loganin upregulated the expression of osteogenic differentiation markers, including Runt-related transcription factor 2(Runx2), ALP, and osterix, while downregulating the expression of apoptosis markers such as cleaved caspase-3 and Bcl-2-associated X protein(Bax) and upregulating the anti-apoptotic protein B-cell lymphoma-2(Bcl-2). Furthermore, loganin inhibited the phosphorylation of the JAK2/STAT3 pathway. Notably, the promoting effect of loganin on osteogenic differentiation and its anti-apoptotic effect were significantly reversed upon treatment with a JAK2/STAT3 pathway agonist, further confirming the critical role of this pathway in its mechanism of action. In conclusion, this study suggests that loganin may alleviate oxidative stress by inhibiting the JAK2/STAT3 signaling pathway, thereby suppressing apoptosis and promoting osteogenic differentiation in MC3T3-E1 cells.