The protective effects of a novel synthetic ß-elemene derivative on human umbilical vein endothelial cells against oxidative stress-induced injury: Involvement of antioxidation and PI3k/Akt/eNOS/NO signaling pathways.

Antioxidant therapy is considered as promising strategy for treating oxidative stress-induced cardiovascular disease. Bis (ß-elemene-13-yl) glutarate (BEG) is a novel ß-elemene derivative. Herein, we examined the antioxidant activity of BEG on human umbilical vein endothelial cells (HUVECs) after injury with hydrogen peroxide (H2O2) and investigated the mechanism involved. HUVECs were divided into the following groups: control group (untreated cells); treated groups (cells treated with 0.1, 1, 10 µmol/L of BEG); positive control group (cells treated with 0.1 mM Vitamin E); model group (cells treated with 0.5 mM H2O2 alone). Cells were pre-incubated with or without BEG for 24 h and then incubated for a further 2 h with 0.5 mM H2O2. Our results showed that BEG significantly reduced H2O2 induced loss in endothelial cell viability, reactive oxygen species (ROS) production, reduced lactate dehydrogenase (LDH) release, and malonyldialdehyde (MDA) level in a concentration-dependent manner. Also, BEG increased the cellular the superoxide dismutase (SOD) activity. Moreover, we found that H2O2 decreased Akt and eNOS phosphorylation, which perhaps, indirectly reduced nitric oxide (NO) production. These effects induced by H2O2, however, were reduced by pre-treatment with BEG. BEG effects were inhibited by a PI3K inhibitor (wortmannin) and eNOS inhibitor (L-NAME). In conclusion, the present study demonstrated that BEG has antioxidant activity. Furthermore, BEG reduced H2O2-induced endothelial cells injury by the involvement of antioxidation and PI3K/Akt/eNOS/NO signaling pathways.

Antioxidant effects and mechanism of silymarin in oxidative stress induced cardiovascular diseases.

Cardiovascular diseases (CVDs) are considered as the major reason for mortality and morbidity worldwide. Substantial evidence suggests that increased oxidative stress plays a significant role in the pathogenesis of CVDs, including atherosclerosis, hypertension, vascular endothelial dysfunction and ischemic heart disease. Cellular oxidative stress results in the release of toxic free radicals by endothelial cells and vascular smooth muscle cells that interact with cell components such as protein, DNA or lipid resulting in cardiovascular pathology. Silymarin has antioxidant activities against CVDs and offers protection against oxidative stress-induced hypertension, atherosclerosis and cardiac toxicity. We present a comprehensive review regarding the oxidative stress and protective effects of silymarin in CVDs management. We also aim to provide mechanistic insight of the mechanisms of silymarin action in oxidative stress-induced CVDs.

Antioxidant therapy for management of oxidative stress induced hypertension.

Hypertension is considered as the most common risk factor for cardiovascular diseases, also is regarded as a leading cause of the mortality and morbidity worldwide. The mechanisms underlying the pathological process of hypertension are not completely explained. However, there is growing evidence that increased oxidative stress plays an important role in the pathophysiology of hypertension. Several preclinical studies and clinical trials have indicated that antioxidant therapy is important for management of hypertension, using antioxidants compounds such as alpha tocopherol (Vit E) and ascorbic acid (Vit C), polyphenols with others and some antihypertensive drugs that are now in clinical use (e.g. ACEIs, ARBs, novel B-blockers, dihydropyridine CCBs) which have antioxidative pleiotropic effects. The purpose of this review is to highlight the importance of antioxidant therapy for management of oxidative stress induced hypertension. Furthermore, we review the current knowledge in the oxidative stress and its significance in hypertension.

Extracellular cysteine/cystine redox potential affects mitochondrial func-tion in NAFLD LO2 cells / 中国病理生理杂志

AIM:To investigate the effects of extracellular cysteine/cystine redox potential (EhCys/CySS) on the mitochondrial function of nonalcoholic fatty liver disease ( NAFLD) hepatocytes.METHODS:LO2 cells were incuba-ted with EhCys/CySS of the oxidized (0 mV), the normal (-80 mV), or the reduced (-150 mV) status medium, then treated with oleic acid to establish NAFLD model in vitro.DCFH-DA and MitoSOX were used as the fluorescent probes for determining reactive oxygen species (ROS).Apocynin (NADPH oxidase inhibitor), MitoQ10 (mitochondria-targeted an-tioxidant), rotenone (mitochondrial respiratory chain complex I inhibitor) and antimycin A (mitochondrial respiratory chain complex III inhibitor) were used to investigate the sources of ROS.RESULTS:An increase in ROS in LO2 cells by oleic acid was aggravated by the oxidized extracellular EhCys/CySS (0 mV), which was removed by the reduced EhCys/CySS (-150 mV) .ROS generation by 0 mV was significantly eliminated by MitoQ10 .ROS levels were dependent on ex-tracellular Eh Cys/CySS in rotenone treated LO2 cells.A decline of mitochondrial membrane potential in the cells with NAFLD was aggravated by 0 mV and reversed by -150 mV.CONCLUSION:The oxidized extracellular Eh Cys/CySS via inhibitiing of complex I intensifies ROS generation and reducing the mitochondrial membrane potential in the NAFLD hepa-tocytes, which were reversed by reduced Eh Cys/CySS.

Effects and mechanisms of mifepristone on insulin-resistant HepG2 cells / 中国药科大学学报

HepG2 cells were pre-incubated with insulin (Ins 0,1,0. 1,0.01 μol/L) and dexamethasone ( Dex 0,3,0. 3,0.03 μol/L) alone or together for 24 h to induce insulin resistance (IR) in vitro, the resistant level was estimated by glucose consumption, the optimal model of insulin resitance was chosen, and at the same time its lasting time of resistance was determined. In order to investigate the effects and mechanisms of mifepristone on in sulin-resistant HepG2 cells induced by insulin and dexamethasone, mifepristone and pioglitazone were adminis tered 24 h after the optimal model of insulin-resistant HepG2 cells was established. The glucose consumption, in tracellular concentrations of glucose, glycogen, ATP, and free fatty acid (FFA) in each group were detected. The expression of InsR-mRNA and GR-mRNA was detected by semi-quantitative reverse transcription and polymerase chain reaction (SqRT-PCR). Results revealed that pretreatment with insulin (0. 1 μmol/L) and dexamethasone (0.3 (μol/L) for 24 h caused optimal insulin resistance of HepG2 cells which lasted for 36 h. Compared with control group, the glucose consumption, intracellular glucose, glycogen, ATP contents and the level of InsR-mRNA in model cells decreased while FFAs concentrations and GR-mRNA increased. However, the tendency of insulin resistant HepG2 cells was obviously attenuated by pioglitazone at the concentration of 0. 2 mmol/L and mifepris tone at 200μmol/L and 20 μol/L while mifepristone at 2 μol/L had no effect on insulin-resistant cells. The findings indicated that mifepristone at 200 μol/L and 20 μol/L improved the insulin resistance via modulating intracellular glucolipid metabolism and the expression of InsR-mRNA and GR-mRNA.

Advances in study of glucocorticoid receptor induced insulin resistance and its antagonists / 中国临床药理学与治疗学

Glucocorticoids are among those most important hormones that maintain the energy metabolic homeostasis within body.The actions of glucocorticoids on target tissues,such as liver and adipose tissue,are not only dependent on circulating glucocorticoid levels but also on glucocorticoid receptor expression.The elevated level of circulating glucocorticoid caused by exogenous or endogenous reasons may contribute to insulin resistance and the other metabolic syndrome such as dyslipidemia,visceral obesity and hypertension.This review summarizes recent advances in the study of glucocorticoid receptor-mediated insulin resistance and its antagonists.