患儿,男,3岁.因"体检发现心脏杂音1年"于2005年6月15日收入院.患儿1年前因"上呼吸道感染"就诊于当地医院,病程中无活动后心慌、气短,无咳嗽、咳痰等症状,易患"上呼吸道感染".入院查体:体温37.2℃,脉搏112次/min,呼吸22次/min,血压110/60 mm Hg(1 mm Hg=0.133kPa).

AIM: To investigate the effect of silymarin on homocysteine-induced cell viability and apoptosis in human umbilical vein endothelial cells (HUVECs). METHODS: Cell viability was analyzed by using MTT and LDH assay. Apoptotic cells were detected by using DNA fragmentation and flow cytometric analysis. The level of intracellular reactive oxygen species (ROS) and the potential of mitochondrial membrane were determined by flow cytometric assay. The activity of caspase-3, -6 and -9 were measured with microplate spectrofluorometer. Protein levels were examined by Western blotting. RESULTS: Treatment of cultured HUVECs with HCY for 48 h induced a significant decrease in cell viability, and the percentage of apoptosis increased to 76.8%. The level of intracellular ROS and activity of caspase-3, -6 and -9 enhanced, and the red/green ratios of mitochondrial membrane decreased. However, simultaneous treatment with silymarin exhibited cytoprotective effects, reduced formation of the DNA ladder, prevented the levels of Bax and Bcl-2 proteins and the accumulation of ROS as well as caspase-3, -6 and -9 activation, reconverted the potential of mitochondrial membrane, and the percentage of apoptosis/necrosis was significantly decreased to 12.7% in a dose-dependent manner. CONCLUSION: These results demonstrate that silymarin has the protective capacity to antagonize HCY-induced apoptosis in HUVECs. The antiapoptotic action of silymarin may be partially dependent on an anti-oxidative stress effects, inhibition of caspases activity, and maintenance of mitochondria function.