Quercetin inhibits mesothelial-mesenchymal transition and alleviates postoperative peritoneal adhesions by blocking the TGF-1/PI3K/AKT pathway

Ethnopharmacological relevance: Carthami flos is a dried flower of the Asteraceae plant Carthamus tinctorius (L.). Danhong injection, composed of Carthami flos and Danshen can prevent the formation of postoperative peritoneal adhesions. Quercetin (QUE), an active compound of Carthami flos, has also been proved to prevent postoperative abdominal and uterine cavity adhesions. However, whether QUE is the key component in Carthami flos and the mechanism in preventing postoperative peritoneal adhesions has not been studied. Aim of the study: To predict whether QUE is the key molecule in Carthami flos and explore the effect and mechanism of QUE in preventing postoperative peritoneal adhesions. Materials and methods: Drug composition and target analysis was used to predict the key component in Carthami flos. The method of cecum-sidewall abrasion was used to establish adhesion models, and the antiadhesion effect of QUE was evaluated with the adhesion scoring system. Network pharmacology was used to predict the targets and potential mechanism of QUE in preventing adhesion. The mechanism was further verified by immunofluorescence, Western blot, wound healing experiment, and molecular docking. Results: Quercetin was predicted to be the key to preventing postoperative peritoneal adhesions in Carthami flos. Animal experiments revealed that QUE effectively ameliorated adhesions and reduced the expression of mesothelial-mesenchymal transition (MMT) related markers and TGF-beta 1. Moreover, the TGF-beta 1/PI3K/AKT pathway was predicted via protein-protein interaction and Kyoto encyclopedia of Genes and Genomes enrichment analysis to play a crucial part in preventing adhesion by QUE. Furthermore, in vitro experiments and molecular docking demonstrated that QUE could block the TGF-beta 1/PI3K/AKT pathway through forming a stable combination with T beta R-II, thereby inhibiting MMT and ameliorating peritoneal adhesion. Conclusions: QUE can not only reduce postoperative TGF-beta 1 but also block the TGF-beta 1/PI3K/AKT pathway to inhibit MMT of mesothelial cells, and finally alleviate postoperative peritoneal adhesions. These findings may provide insights towards development of a safe and effective anti-adhesive drug for prevention of postoperative peritoneal adhesions.