Effects of short-chain acyl-CoA dehydrogenase on human umbilical vein endothelial cell apoptosis / 中华危重病急救医学

Objective To observe the changes of short-chain acyl-CoA dehydrogenase (SCAD) expression on human umbilical vein endothelial cell (HUVEC) apoptosis and investigate its relationship with apoptosis. Methods The HUVEC was cultured normally for 2-3 days. The apoptotic model of HUVEC was established by tert-butyl hydrogen peroxide (tBHP). The HUVEC was treated by different concentrations of tBHP (0, 10, 20, 30, 40, 50 μmol/L) for 12 hours and different time (0, 3, 6, 9, 12 hours) with 50 μmol/L tBHP to establish the apoptotic model of HUVEC. The cell viability was detected by methyl thiazolyl tetrazolium (MTT), the mRNA expression of SCAD was determined by real-time polymerase chain reaction (PCR), the protein expression of SCAD was achieved by Western Blot. The best concentrate and time were determined to interfere the HUVEC to achieve the apoptotic model of HUVEC. The SCAD gene of HUVEC was knocked down by RNA interference sequence (siRNA274, siRNA414, siRNA679). The mRNA expression of SCAD, the protein expression of SCAD and the activity of SCAD enzyme were detected to achieve the best RNA interference sequence. The HUVEC was intervened by the best RNA interference sequence and tBHP. The cell activity and apoptosis rate, the enzyme activity of SCAD, the mRNA and protein expression of SCAD, the contents of reactive oxygen species (ROS), aderosine triphosphate (ATP) and free fatty acid (FFA) were detected to observe the effect of SCAD on apoptosis of HUVEC. Results ① The cell viability, the mRNA expression and the protein expression of SCAD were decreased gradually in a concentration and time dependent manner with the increase of tBHP concentration and the prolongation of intervention time. The decline was most significant in the group of the 50 μmol/L tBHP to interfere HUVEC for 12 hours. ② The siRNA679 transfection was the most significant in reducing SCAD mRNA and protein expressions among the three interference sequences (siRNA274, siRNA414, siRNA679). ③ Compare with blank control group, the cell viability was significantly decreased in the siRNA679 group (A value: 0.48±0.09 vs. 1.00±0.09, P < 0.01), the apoptotic rate of HUVEC was significantly increased [(29.96±2.09)% vs. (2.90±1.90)%, P < 0.01], the expression of SCAD mRNA and SCAD protein, the activity of SCAD enzyme and the content of ATP were significantly decreased [SCAD mRNA (2-ΔΔCt): 0.50±0.16 vs. 1.34±0.12, SCAD/α-Tubulin: 0.67±0.11 vs. 1.00±0.06, the activity of SCAD enzyme (kU/g): 0.38±0.04 vs. 0.53±0.04, the content of ATP (μmol/g): 0.14±0.02 vs. 0.19±0.01, all P < 0.05], the contents of FFA and ROS were significantly increased [FFA (nmol/g): 0.84±0.07 vs. 0.47±0.04, ROS (average fluorescence intensity): 647.5±23.7 vs. 434.2±46.5, both P < 0.01]. Meanwhile, SCAD siRNA treatment triggered the same apoptosis as HUVEC treated with tBHP. Conclusions Down-regulation of SCAD may play an important role in HUVEC apoptosis. Increase in the expression of SCAD may become an important part in intervening HUVEC apoptosis.

Lycopene protects primary mouse cerebrocortical neurons against t-BHP-induced damage in vitro / 中国病理生理杂志

AIM:To investigate the protective effect of lycopene on primary mouse cerebrocortical neurons ex -posed to tert-butyl hydroperoxide ( t-BHP) and its mechanisms of in vitro.METHODS:Primary cerebrocortical neurons of newborn C57 mice were extracted and divided into normal group , t-BHP group, lycopene +t-BHP group and lycopene group.The neuronal damage was induced by t-BHP exposure for 24 h, and the cell viability was examined by MTT assay . ROS content was measured by flow cytometry , and the protein levels of Bax , Bcl-2, caspase-3, cleaved caspase-3 and cyto-chrome C were examined by Western blot .RESULTS:The primary mouse cortical neurons expressed MAP-2 protein.Ly-copene at concentration of 4μmol/L reversed the decrease in cell viability .Flow cytometry revealed that lycopene treatment attenuated ROS content under the condition of t-BHP exposure.In addition, the protein level of Bcl-2 was increased, and the expression of Bax , cleaved caspase-3 and cytochrome-C was suppressed in lycopene +t-BHP group.CONCLUSION:The protective effect of lycopene on cortical neurons with t-BHP-induced injury may be involved in the mechanism of neuro-nal antioxidative response by down-regulating caspase-3 and Bax/Bcl-2 through the mitochondrial apoptotic pathway .

Effects of short-chain acyl-CoA dehydrogenase on cardiomyocyte apopto-sis / 中国病理生理杂志

AIM:To investigate the change of short-chain acyl-CoA dehydrogenase (SCAD) expression during cardiomyocyte apoptosis and to explore the relationship between SCAD and cardiomyocyte apoptosis .METHODS: The neonatal rat cardiomyocytes treated by tert-butyl hydroperoxide (tBHP) were used as the model of cardiomyocyte apoptosis . The cell viability , the expression of SCAD at mRNA and protein levels , the activity of SCAD and the content of free fatty acids were determined .RESULTS:The mRNA and protein expression of SCAD decreased in the cardiomyocyte apoptosis model.Compared with negative control group , SCAD expression and activity were both significantly decreased in siRNA-1186 group, but the content of free fatty acids were obviously increased in the cardiomyocytes .Meanwhile, SCAD siRNA treatment triggered the same apoptosis as cardiomyocytes treated with tBHP .CONCLUSION: Down-regulation of SCAD may play an important role in primary cardiomyocyte apoptosis .Increase in the expression of SCAD may become an impor-tant part in intervening cardiomyocyte apoptosis .

Schisandra Chinensis Baillon regulates the gene expression of phase II antioxidant/detoxifying enzymes in hepatic damage induced rats

BACKGROUND/OBJECTIVES: This study investigated the antioxidant activities and hepatoprotective effects of Schisandra chinensis Baillon extract (SCE) against tert-butyl hydroperoxide (t-BHP)-induced oxidative hepatic damage in rats. MATERIALS/METHODS: Sprague-Dawley (SD) rats were pretreated with SCE (300, 600, and 1,200 mg/kg BW) or saline once daily for 14 consecutive days. On day 14, each animal, except those belonging to the normal control group, were injected with t-BHP (0.8 mmol/kg BW/i.p.), and all of the rats were sacrificed 16 h after t-BHP injection. RESULTS: Although no significant differences in AST and ALT levels were observed among the TC and SCE groups, the high-dose SCE group showed a decreasing tendency compared to the TC group. However, erythrocyte SOD activity showed a significant increase in the low-dose SCE group compared with the TC group. On the other hand, no significant differences in hepatic total glutathione (GSH) level, glutathione reductase (GR), and glutathione peroxidase (GSH-Px) activities were observed among the TC and SCE groups. Hepatic histopathological evaluation revealed that pretreatment with SCE resulted in reduced t-BHP-induced incidence of lesions, such as neutrophil infiltration, swelling of liver cells, and necrosis. In particular, treatment with a high dose of SCE resulted in induction of phase II antioxidant/detoxifying enzyme expression, such as glutathione S-transferase (GST) and glutamate-cysteine ligase catalytic subunit (GCLC). CONCLUSIONS: Based on these results, we conclude that SCE exerts protective effects against t-BHP induced oxidative hepatic damage through the reduction of neutrophil infiltration, swelling of liver cells, and necrosis. In addition, SCE regulates the gene expression of phase II antioxidant/detoxifying enzymes independent of hepatic antioxidant enzyme activity.

Effects of tert-butyl hydroperoxide on Ca2+ ATPase activity in isolated rat hepatocytes and its reversal by antioxidants.

Calcium ions play an important role in various physiological processes such as nerve impulse transmission, muscle contraction, hormone action, blood clotting. They ions act as an intracellular second messenger, relaying information within cells to regulate their activity. To understand the mechanism of hepatotoxicity of t-BHP, studies were carried out using freshly isolated rat hepatocytes. The effect of t-BHP on Ca2+ accumulation and Ca2+ uptake by rat hepatocytes was monitored using 45Ca2+. It caused decrease in 15% accumulation of 45Ca2+ in comparison to the control group. t-BHP also significantly decreased the Ca2+ ATPase activity in isolated hepatocytes. This decrease in Ca2+ATPase activity by t-BHP was reversed 40% by naturally occurring antioxidant glutathione (GSH) and 20% by the synthetic antioxidant butylated hydroxy toluene (BHT). These results indicate that the hepatotoxic action of t- BHP involves oxidative stress as evident by the protection accorded by various antioxidants employed in the study as well as impairment of intracellular calcium homeostasis which can lead to liver cell injury.

Study on the senescence of rat glomerular mesangial cells induced by Tert-Butyl hydroperoxide in vitro and the influnce of probucol on its senescence / 中国综合临床

Objective To investigate the senescence of rat mesangial cells induced by Tert-Butyl hydroperoxide (tBHP) and the protective effect of probucol on senesecence. Methods Human glomerular mesangial cells(hGMC) were cultured in vitro and intervened by tBHP. The cell survival rate was observed by methyl thiazolyl tetrazolium( MTT). β-gal staining and cell cycle analysis were used to identify cell senescent status;transmission eletric microscopy was used to evaluate the ultra-microstructure of hGMC. Senescent-related indexes were detected after treatment with probucol. Results The cell survival rate with 30 μmol/L tBHP was (80. 12 ± 3. 25 ) % , the positive rate of β-gal staining was significantly higher in tBHP-induced cells (about 81% )than that of the control cells( P <0. 01). 86% of the cells was arrested at G0-G1 phase. Invagination of nucleus membrane and chromatin condensation at the nuclear margin in tBHP-induced cells was observed through transmission eletric microscopy. In the probucol intervented cells, the cell survival rate was higher than that of tBHP-induced cells (92. 68 ± 5.03) % vs. ( 80. 12 ± 3. 25) % (P < 0. 05 ). The positive rate of β-gal staining decreased to 45. 2%. The proportion of cell cycle stage was similar to the control cells.The change of morphous and ultrastructure was relieved. Conclusions tBHP can induce hGMC senescence in vitro and probucol may play a role in preventing hGMC senescence.

Assessment of Hemorheological Deformability of Human Red Cells Exposed to tert-Butyl Hydroperoxide, Verapamil and Ascorbate by Ektacytometer / 대한진단검사의학회지

BACKGROUND: Normal erythrocyte is deformable and this facilitates blood flow in the capillaries. Oxidative stress reduces the deformability of erythrocytes, and influences on blood flow in microcirculation. The objective of this study was to investigate the deformability of erythrocytes exposed to oxidative stress, the protective effects of verapamil and ascorbic acid against oxidative damages in erythrocytes, and the value of the microfluidic ektacytometer, RheoScan-D (RheoMeditech, Korea) in clinical application. METHODS: Effects of oxidative stress on erythrocytes were investigated using tert-butyl hydroperoxide (tBHP). Before exposure to tBHP, the erythrocytes were pretreated with verapamil and ascorbic acid to examine their protective effect against oxidative damages. The deformability of erythrocytes was measured by the microfluidic ektacytometer, RheoScan-D. RESULTS: When treated with tBHP, the deformability of erythrocytes was decreased (P<0.01) and methemoglobin (metHb) formation and mean corpuscular volume (MCV) of erythrocytes were increased (P<0.01, P<0.05) compared to those of the untreated control cells. Compared to the tBHP treated cells, pretreatment with verapamil increased the deformability of erythrocytes (P<0.01) and decreased metHb formation (P<0.01) and MCV (P<0.05). Likewise, pretreatment with ascorbic acid increased the deformability of erythrocytes (P<0.01) and decreased metHb formation (P<0.01). CONCLUSIONS: Oxidative stress reduces the deformability of erythrocytes and the deformability could be one of markers for oxidative damage. Verapamil and ascorbic acid have protective role against tBHP induced oxidative stress. The ektacytometer, RheoScan-D used in this study is convenient for clinical measurement and could be used in various fields of clinical medicine.

The mechanism of t-butylhydroperoxide-induced apoptosis in IMR-32 human neuroblastoma cells

Apoptosis has been implicated in the pathophysiological mechanisms of various neurodegenerative diseases. In a variety of cell types, oxidative stress has been demonstrated to play an important role in the apoptotic cell death. However, the exact mechanism of oxidative stress-induced apoptosis in neuronal cells is not known. In this study, we induced oxidative stress in IMR-32 human neuroblastoma cells with tert-butylhydroperoxide (TBHP), which was confirmed by significantly reduced glutathione content and glutathione reductase activity, and increased glutathione peroxidase activity. TBHP induced decrease in cell viability and increase in DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. TBHP also induced a sustained increase in intracellular Ca2+ concentration, which was completely prevented either by EGTA, an extracellular Ca2+ chelator or by flufenamic acid (FA), a non-selective cation channel (NSCC) blocker. These results indicate that the TBHP-induced intracellular Ca2+ increase may be due to Ca2+ influx through the activation of NSCCs. In addition, treatment with either an intracellular Ca2+ chelator (BAPTA/AM) or FA significantly suppressed the TBHP-induced apoptosis. Moreover, TBHP increased the expression of p53 gene but decreased c-myc gene expression. Taken together, these results suggest that the oxidative stress-induced apoptosis in neuronal cells may be mediated through the activation of intracellular Ca2+ signals and altered expression of p53 and c-myc.

Role of Ca2+ influx in the tert-butyl hydroperoxide-induced apoptosis of HepG2 human hepatoblastoma cellse

Oxidative stress appears to be implicated in the pathogenesis of various diseases including alcoholic liver injury. In this study we investigated the mechanism of apoptosis induced by tert-butyl hydroperoxide (TBHP) in HepG2 human hepatoblastoma cells. Treatment with TBHP significantly reduced glutathione content and glutathione reductase activity, and increased glutathione peroxidase activity, indicating that TBHP induced oxidative stress in the HepG2 cells. TBHP also induced reduction of cell viability and DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. In addition, TBHP induced a sustained increase in intracellular Ca2+ concentration, which was completely prevented by the extracellular Ca2+ chelation with EGTA. TBHP also induced Mn2+ influx. These results indicate that the intracellular Ca2+ increase by TBHP is exclusively due to Ca2+ influx from the extracellular site. Treatment with either an extracellular (EGTA) or an intracellular Ca2+ chelator (BAPTA/AM) significantly suppressed the TBHP-induced apoptosis. Taken together, these results suggest that TBHP induced the apoptotic cell death in the HepG2 cells and that Ca2+ influx may play an important role in the apoptosis induced by TBHP.

Effects of tert-butyl hydroperoxide and hypoxia in transient ischemia-like attack in mice / 临床神经病学杂志

Objective To explore the effects and relationship of tert-butyl hydroperoxide (t-BHP) and hypoxia in transient ischemia-like attack (TIA-like) in Kunming mice.Methods Fifty-six mice were randomly divided into normal saline group (group A), t-BHP group (group B), t-BHP plus hypoxia group (group C) and model group (group D). Fourteen mice in group D were injected t-BHP (0.11 mol/L, 10 ml/kg) through tail vein with an interval of 24 hrs to induce TIA-like attack. The average time of TIA-like was ( 3.7? 1.1) days, and this time was used as experimental evidence to collect blood sample in other groups. Hemorheological indexes before TIA-like attack were observed in different experimental conditions.Results Compared with group A, the whole blood viscosity at shear rate 100S-1, 1S-1 and Fibrinogen were significantly increased in group B and group C (all P