Protective effect of quercetin on lipopolysaccharide‑induced miscarriage based on animal experiments and network pharmacology.

Spontaneous abortion (SA) occurs in woman of child‑bearing age, jeopardizing their physical and mental health. Quercetin is a natural flavonoid, which exhibits a variety of pharmacological activities. However, the role and mechanisms of quercetin in SA still need to be further explored. Animal experiments were performed to examine the effect of quercetin in treating SA. Institute of Cancer Research mice were injected with lipopolysaccharide into the tail vein on the 7th day of gestation to establish a SA model. Gavage was performed during days 3‑8 of gestation with high‑, medium‑ and low‑dose of quercetin. Then the effect of quercetin on embryos was evaluated. Animal experiment showed that quercetin could remarkably reduce the embryo loss rate and increase the mean weight of surviving embryos to some degree. Furthermore, network pharmacology was employed to explore the underlying mechanisms of quercetin in the treatment of SA. Several databases were used to collect the targets of SA and quercetin. Protein‑protein interaction network, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were performed to elucidate the interactions between SA and quercetin. The relative mRNA expressions of several targets in uterine were detected by quantitative reverse transcriptase polymerase chain reaction (RT‑qPCR). Network pharmacology indicated that the effects of quercetin in treating SA were mainly related to hormone response and the modulation of defense response and inflammatory response, involving signaling pathways such as PI3K‑Akt, VEGF, MAPK and core targets such as AKT1, albumin, caspase‑3. RT‑qPCR showed that quercetin could up‑regulate AKT1, MAPK1, PGR, SGK1 and down‑regulate ESR1, MAPK3. The results showed that quercetin may modulate multiple signaling pathways by targeting core targets to prevent and treat SA.