OBJECTIVETo explore targets of Chinese herbal medicine at cellular and molecular leve1s through an experimental study on Yinxingye Capsule (YC) intervening vascular endothelial cell apoptoeis of hyperhornocysteinemia (HHcy) rats.METHODSThe HHcy model was prepared in male Wistar rats. Totally 42 rats were randomly divided into 4 groups, i.e., the control group (n =10), the model group (n = 11), the YC group (n =11), the folic acid group (n =10). Carboxy methyl cellulose (CMC) solution (1%) was administered to rats in the control group by gastrogavage.3% methionine suspension at 1. 5 g/kg was administered to rats in the model group by gastrogavage. 3% methionine suspension at 1. 5 g/kg and folic acid suspension at 0. 06 g/kg was administered to rats in the folic acid group by gastrogavage. 3% methionine suspension at 1. 5 g/kg and YC at 0. 02 g/kg was administered to rats in the YC group by gastrogavage. Morphological changes of aortic tissue were observed by hematoxylin eosin (HE) staining. The plasma homocysteine (Hcy) level was detected in each group. The endothelium-dependent diastolic functions of the thoracic aorta on different concentrations of sodium nitroprusside (SNP) and acetylcholine (Ach) were detected. Gene expressions of Bcl-2-associated X protein (BAX), inducible nitric oxide synthase (iNOS), c-Fos, cellular inhibitor of apoptosis protein 2 (c-IAP2) were detected by real time polymerase chain reaction (RT-PCR).RESULTSPathological results showed that thickening aortic endothelium, swollen and desquamated endothelial cells. Few foam cells could be seen in the model group. Myoma-like proliferation of smooth muscle cells in tunica media could also be seen. These pathological changes were milder in the YC group and the folic acid group. Compared with the control group, plasma Hcy levels increased in the model group (P <0. 05). The endothelium-dependent diastolic rates at 10(-6) and 10(-4)mol/L Ach and 10(-7) -10(-3)mol/L SNP all decreased in the model group (P <0. 01, P <0. 05). Gene expressions of Bax, c-Fos, and iNOS increased, but c-IAP2 gene expressions decreased in the model group (all P <0. 05). Compared with the model group, plasma Hcy levels decreased in the YC group and the folic acid group (P <0. 05). The endothelium-dependent diastolic rates increased in the YC group and the folic acid group at various SNP concentrations except 10(-6) mol/L SNP in the folic acid group. The endothelium-dependent diastolic rates increased in the YC group and the folic acid group at 10(-6) and 10(-4)mol/L Ach (all P <0. 05). Gene expressions of Bax, c-Fos, and iNOS decreased in the YC group and the folic acid group, but c-IAP2 gene expression increased in the folic acid group (all P <0. 05).CONCLUSIONYC could reduce plasma Hcy levels, down-regulate gene expressions of Bax, c-Fos, and iNOS, thereby reducing apoptosis of vascular endothelial cells, improving vascular endothelial function, and delaying atherosclerotic process.