Objective To observe the protective effect of α-lipoic acid (LA) pretreatment on hypoxia/reoxyg-enation injury in vascular endothelial cells and preliminary explore its mechanism. Methods HUVEC were cultured intro and devided into control group,hypoxia/reoxygenation model group and LA group. Cell morphology was observed under inverted phase contrast microscope,cell viability was detected by MTT,total antioxidant capacity (TAOC),nitric oxide(NO),malondialdehyde (MDA),superoxide dismutase (SOD) activity or level were measured by various commercial kits respectively. Apoptosis of HUVEC in each group were detected by flow cytometry , cleaved caspase-3 level was measured by western blot. Results As compared to control group, the survival rate, TAOC, SOD, NO activity were significantly lower(P<0.05), and MDA level, apoptosis rate and apoptosis protein levels were significantly higher (P < 0.05) in model group. However,LA can increase the survival rate,TAOC, SOD,NO activity (P < 0.05),reduce MDA level and cell apoptosis (P < 0.05)in a dose dependent manner. Conclusion LA pretreatments provide protection against hypoxia/reoxygenation injury in HUVEC. LA exerts protective effects through inhibition of HUVEC apoptosis.

Objective To study the protective effects ofαt-lipoic acid (LA) on rat C6 glioma cells (C6 cells) exposed to hypoxia/reoxygenation and its mechanism.Methods Rat glioma cells C6 were conventionally in vitro cultured and cells at logarithmic growth phase were used in the experiment.Normal control group,oxygen-glucose deprivation/reoxygenation (OGD/ROG) model group,and OGD/ROG plus 10,25 and 50 μmol/L LA treatment groups were chosen.C6 cells were exposed to OGD/ROG to simulate ischemia/reperfusion in vitro.Different concentrations of LA (10,25 and 50μmol/L) were added to the culture medium in the later three groups 12 h before hypoxia.Twelve h after C6 cells reperfusion,cell viability was analyzed by MTT assay; flow cytometry was used to evaluate the level of cellular reactive oxygen species (ROS) and Annexin V/PI staining to examine cell apoptosis rate;the expression of cleaved Caspase-3 protein was determined by Western blotting.Results As compared with normal control group,OGD/ROG model group,and OGD/ROG plus 10,25 and 50 μmol/L LA treatment groups had significantly decreased cell viability and increased cell apoptosis rate (P＜0.05); as compared with that in the normal control group,ROS level in the model group was statistically increased,while that in the 50 μmol/L LA treatment group was significantly decreased (P＜0.05); as compared with that in the normal control group,Caspase-3 expression in the model group and 10 μmol/LA treatment group was significantly increased (P＜0.05).As compared with the model roup,the 25 and 50 μmol/L LA treatment groups had significantly higher cell viability,the 10,25 and 50 μmol/L LA treatment groups had significantly lower ROS level,cell apoptosis rate and Caspase-3 expression (P＜0.05).Conclusion LA has a protective effect on injury in C6 cells induced by hypoxia/reoxygenation,whose mechanism may be related to LA eliminating excess cellular ROS,preventing occurrence of oxidative damage and thereby inhibiting Caspase-3 pathway-dependent apoptosis in C6 cells.

OBJECTIVE：To study the effects of costunolide on the proliferation ，migration and apoptosis of breast cancer SK-BR-3 cells and its mechanism. METHODS ：SK-BR-3 cells in logarithmic growth period were collected and cultured with different concentrations （10，20，30，40，50 μmol/L）of costunolide for 24，48，72 h. Inhibitory rate of costunolide on cell proliferation was detected with CCK- 8. The cells were divided into blank control group and costunolide group （10，20，30 μmol/L）. Hoechst 33258 fluorescence was used to observe the morphology and apoptosis of cells ，and apoptotic rate of cells were calculated. Cell scratch test was used to detect the migration ability of cells and calculate the migration rate. Western blotting was used to detect the relative expression level of Bcl- 2，Bax，Caspase-3 and Cleaved Caspase- 3 in cells. RESULTS ：The proliferation of SK-BR-3 cells were significantly inhibited by costunolide （P＜0.05 or P＜0.01），and it shows a trend of concentration and time dependence. In the blank control group ，cells possessed clear contour ，regular shape and good adherence . Compared with blank control group，the number of cells were decreased significantly in 10，20，30 μmol/L costunolide groups，the cell structure was loose，the volume was reduced ，and the gap became larger ，and most of the cell contour disappeared and became round ，the cell adherence was poor ；cell migration rate and Bcl- 2 protein relative expression level were decreased significantly ，while apoptosis rate and the relative expression level of Bax ，Caspase-3 and Cleaved Caspase- 3 protein were significantly increased （P＜0.05 or P＜0.01）. CONCLUSIONS ： Costunolide can inhibit the proliferation and migration ，and induce apoptosis of human breast cancer SK-BR- 3 cells，mechanism of which may be through up-regulating the expression of Bax ，Caspase-3 and Cleaved Caspase- 3 while down-regulating the expression ofBcl-2.