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.

To assess relationships between xanthine oxidase (XOD) and nephropathogenic infectious bronchitis virus (NIBV) infection, 240 growing layers (35 days old) were randomly divided into two groups (infected and control) of 120 chickens each. Each chicken in the control and infected group was intranasally inoculated with 0.2 mL sterile physiological saline and virus, respectively, after which serum antioxidant parameters and renal XOD mRNA expression in growing layers were evaluated at 8, 15 and 22 days post-inoculation (dpi). The results showed that serum glutathione peroxidase and superoxide dismutase activities in the infected group were significantly lower than in the control group at 8 and 15 dpi (p < 0.01), while serum malondialdehyde concentrations were significantly higher (p < 0.01). The serum uric acid was significantly higher than that of the control group at 15 dpi (p < 0.01). In addition, the kidney mRNA transcript level and serum activity of XOD in the infected group was significantly higher than that of the control group at 8, 15 and 22 dpi (p < 0.05). The results indicated that NIBV infection could cause the increases of renal XOD gene transcription and serum XOD activity, leading to hyperuricemia and reduction of antioxidants in the body.
Antioxidants ; Chickens ; Glutathione Peroxidase ; Hyperuricemia ; Infectious bronchitis virus* ; Kidney ; Malondialdehyde ; RNA, Messenger* ; Superoxide Dismutase ; Uric Acid ; Xanthine Oxidase* ; Xanthine*