Abstract:To explore the protective effect of hydroxytyrosol （HT），a natural food active ingredient，on lipid metabolism and vascular endothelial injury in rats with atherosclerosis （AS），an AS rat model was established by feeding a high-fat diet combined with vitamin D3 and L-methionine. The rats were randomly divided into the normal group，model control group，HT low-dose group，HT high-dose group，and atorvastatin positive group.After continuous intragastric administration intervention，serum lipid profiles，liver function indexes，oxidative stress indicators and inflammatory factors were detected. Hematoxylin-eosin （HE） staining and Oil Red O staining were performed to observe the pathological morphology and lipid deposition of liver and aortic tissues.The results demonstrated that the rat AS model was successfully constructed. HT intervention significantly regulated serum lipid levels，improved liver function，inhibited oxidative stress，and reduced the activities of vascular injury-related indicators，with superior efficacy observed in the HT high-dose group. Pathological staining results further verified that HT markedly alleviated hepatic steatosis，reduced lipid deposition in the liver and aorta，and ameliorated aortic intimal injury. In conclusion，HT exerts prominent protective effects against atherosclerosis in model rats by regulating lipid metabolism，improving hepatic function，suppressing oxidative stress and inflammatory responses，and alleviating vascular endothelial damage and lipid accumulation. This study provides a reliable experimental basis for the further development of HT as a functional food factor and its application in dietary intervention for atherosclerosis.