Total triterpenes from fruits of Chaenomeles speciosa(Sweet) Nakai protect against indomethacin-induced gastric mucosal injury: involvement of TFF1-mediated EGF/EGFR and apoptotic pathways

OBJECTIVE Gastric ulcers affect people of all ages and half of the world's population,which is being considered as the new"plague of the 21st century".As is well known,gastric mucosa is known as the first guard to protect the stomach from ulcer injury,while the aetiology of gastric ulcer is relative to imbalances between gastric mucosal protective and aggressive factors.Therefore,reducing or eliminating the aggressive factors,returning to the balance of between mucosal protective and aggressive factors,and then restoring the normal functional of gastric mucosal barrier could be crucial for treating the gastric ulcer.The fruits of Chaenomeles speciosa(TCS),also known as"mugua",might be processed into edible and health care derived products,and used as a commonly used traditional medicine in China for thousands of years.In China folk,there is a saying that"apricot one benefit,pear two benefits,mgua hundred benefits",so it has a"hundred-benefit"fruit reputation.Tujia nationality inhabitants in Southwestern China should have rheumatic diseases and peptic ulcers for living in the damp environments and bingeing on spicy and pungent foods.For the exis⁃tence of the fruit derived products of Chaenomeles speciosa as their complementary foods or snacks,the habit makes them rarely suffer from the two kinds of diseases.Enlightened by these,we had investigated the structure-activity rela⁃tionships,screened out CSTT with gastroprotective activity.Our previous studies demonstrated that TCS owned effec⁃tively therapeutic effects on gastric ulcer patients and animals,and further confirmed that TFF1 and apoptotic pathway were closely interrelated with its exerting gastroprotection.However,its underlying molecular mechanisms involved have not been fully elucidated.The current study was to further investigate its protective effect on indomethacin(IND)-damaged RGM-1 cells and rats and its underlying mechanisms through modulating TFF1-mediated EGF/EGFR and apoptotic pathways.METHODS The gastroprotection of TCS was evaluated with IND-induced gastric lesions model in RGM-1 cells and rats.In vitro,the proliferation,migration,mitochondrial viability and apoptosis were assessed,In vivo,ulcer index,ulcer inhibition rate,gastric juice acidity,gastric wall mucus(GWM),histopathology of gastric mucosa were detected.The gastroprotective effects of TCS through the TFF1-mediated EGFR/EGFR and apoptotic pathways were presented and measured by qRT-PCR and Western blotting assays.RESULTS TCS had gastroprotective function,which was related to the amelioration in promoting IND-damaged RGM-1 cell proliferation and migration,hoisting gastric juice acidity and GWM,improving ulcer index and ulcer inhibition rate,attenuating the hemorrhage,edema,epithelial cell loss and inflammatory cell infiltration of gastric mucosa,upregulating proliferation cell nuclear antigen,Bcl-2,Bcl-xl mRNA and TFF1,EGF,p-EGFR,p-Src,pro-caspase-3,pro-caspase-9 protein expressions,mitochondrial viability,mitochondrial cytochrome C concentration and p-EGFR/EGFR,p-Src/Src,Bcl-2/Bax,Bcl-xl/Bad ratioes,downregulating Bax,Bad,Apaf-1 mRNA and cleaved-caspase-3,cleaved-caspase-9,cleaved-PARP-1 protein expressions,cytosol cytochrome C concentration.CONCLUSION TCS′s gastroprotective effect was closely connected with boosting TFF1 expression,acti⁃vating TFF1-mediated EGF/EGFR pathway,thus restraining mitochondrial-dependent apoptosis,which provided new insights into interpreting its underlying mechanism and promised to act as a candidate drug to treat gastric mucosal injury.