OBJECTIVETo investigate the mechanism of low glucose-induced injury in human ECV304 cells.

METHODSHuman umbilical vein endothelial cell line ECV304 were stimulated with low concentrations of glucose. The level of reactive oxygen species (ROS) in cells was detected at different time points within 12 h by kinetic measurement of dichlorofluorescein (DCF) fluorescence produced by oxidation of an oxidant-sensitive dye 2,7-dichlorofluorescein (DCFH). ECV304 cell viability was assessed with MTT assay and NADPH oxidase activity detected using lucigenin-enhanced chemiluminescence assay following cell stimulation with low glucose and apocynin.

RESULTSLow-glucose exposure of ECV304 cells time- and dose-dependently induced ROS production, and which was decreased by apocynin treatment. Apocynin pretreatment of the cells inhibited ROS production by 44% in cells exposed to 2.8 mmol/L glucose and by 60% in cells without glucose exposure.

CONCLUSIONSLow glucose of ECV304 cells induces ROS production to cause cell injury, which is mediated partially by NADPH oxidase activation.

Cell Line ; Glucose ; administration & dosage ; adverse effects ; Humans ; NADPH Oxidases ; metabolism ; Oxidative Stress ; drug effects ; Reactive Oxygen Species ; metabolism

The objective of this study was to investigate the protection by naringenin against doxorubicin-induced oxidative damage in normal blood cells. Inhibiting effects of naringenin, doxorubicin and naringenin combined with doxorubicind on K562 cells and polymorphonuclear leukocytes were detected with MTT method, the level of reactive oxygen species (ROS) and lipid peroxidation (MDA), the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were examined with spectrophotometric method in the K562 cells and polymorphonuclear leukocytes. The results indicated that the proliferation of K562 cells was not inhibited by the cytotoxicity of doxorubicin in combination of naringenin with doxorubicin. As compared with the doxorubicin, the addition of naringenin after doxorubicin for 1 hour, the levels of reactive oxygen species (ROS) and lipid peroxidation (MDA) obviously decreased, the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) obviously increased in the polymorphonuclear leukocytes, but these were not changed obviously in K562 cells. It is concluded naringenin can protect against doxorubicin-induced oxidative damage in normal blood cells. The mechanism of naringenin may be elevating activities of antioxidant enzyme and degrading oxidative production level in normal blood cells, and meanswhile decreasing level of oxidative products.
Antioxidants ; pharmacology ; Doxorubicin ; adverse effects ; Erythrocytes ; drug effects ; Flavanones ; pharmacology ; Humans ; Oxidative Stress ; Reactive Oxygen Species ; metabolism ; Superoxide Dismutase ; metabolism

OBJECTIVE: To observe whether necroptosis was happened in high glucose (HG) - induced primary cardiomyocytes injury and to investigate the likely mechanism. METHODS: The primary cultured cardiomyocytes were divided into 4 groups (n=9): control group (the cardiomyocytes were incubated with 5.5 mmol/L glucose for 48 h), HG group (the cardiomyocytes were incubated with 30 mmol/L glucose for 48 h), HG + necrostatin-1 (Nec-1) group (the cardiomyocytes was co-incubated with necroptosis inhibitor Nec-1 at 100 μmol/L and HG for 48 h) and hypertonic pressure group (HPG, the cardiomyocytes was co-incubated with 5.5 mmol/L glucose and 24.5 mmol/L mannitol for 48 h). Cell viability was measured by MTT method, reactive oxygen species (ROS) generation was measured by DHE staining. The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were tested by ELISA method. The mRNA and protein expressions of necroptosis related genes receptor interacting serine/threonine protein kinase 1 (RIP1), RIP3, mixed lineage kinase domain-like protein (MLKL) were tested by quantitative real-time PCR and Western blot. RESULTS: The results showed HG intervention decreased cardiomyocytes viability, increased ROS generation, up-regulated the levels of TNF-α, IL-6 and IL-1β, increased RIP1, RIP3, MLKL expressions at mRNA and protein levels. Nec-1 treatment attenuated HG-induced increased cardiomyocytes viability, reduced ROS generation, down-regulated the levels of TNF-α, IL-6 and IL-1β, decreased RIP1, RIP3, MLKL expressions at mRNA and protein levels. CONCLUSION Necroptosis was happened in high glucose-induced primary cardiomyocytes injury. Inhibition of necroptosis can reduce high glucose-induced cardiomyocytes damage, may be related to inhibition of oxidative stress and depression of inflammative factors releasing.
Apoptosis ; Cells, Cultured ; Cytokines ; metabolism ; Glucose ; adverse effects ; Humans ; Myocytes, Cardiac ; cytology ; pathology ; Necrosis ; Oxidative Stress ; Reactive Oxygen Species ; metabolism

Animals ; Cochlea ; metabolism ; Environmental Exposure ; adverse effects ; Hearing Loss, Noise-Induced ; metabolism ; Humans ; Noise ; adverse effects ; Oxidative Stress ; physiology ; Reactive Oxygen Species ; metabolism

Oxidative stress and lipid peroxidation have been implicated in the pathogenesis of various diseases, including atherosclerosis and fatty liver diseases, and consequently the role of antioxidants in the prevention and treatment of such diseases has received much attention. In particular, the effects of vitamin E, the most important lipophilic radical-scavenging antioxidant, have been investigated extensively. Many in vitro, animal, and epidemiological studies have reported positive results, but large-scale randomized controlled intervention studies and meta-analyses have produced inconsistent and often disappointing results. In the present review article, the role and action of vitamin E are discussed, with consideration of the factors that determine the outcome of vitamin E treatment. Vitamin E should benefit subjects experiencing oxidative stress due to free radicals when administered at the correct time and for an appropriate duration.
Animals ; Antioxidants/adverse effects/*therapeutic use ; Humans ; Lipid Peroxidation/*drug effects ; Oxidative Stress/*drug effects ; Reactive Oxygen Species/*metabolism ; Vitamin E/adverse effects/*therapeutic use

OBJECTIVETo investigate the protective effects of dexmedetomidine (Dex) against glutamate-induced cytotoxicity in PC12 cells and its mechanism.

METHODSPC12 cells were treated with varying concentrations of dexmedetomidine 1 h before exposure to a high concentration of glutamate. The cell viability was measured by MTT assay, and LDH release, MDA content and SOD activity were measured. The level of ROS was tested by DCFH-DA staining and flow cytometry. The level of intracellular Cawas detected by Fluo-8 staining and flow cytometry, and the mitochondrial membrane potential (MMP) was determined with JC-1 staining and flow cytometry.

RESULTSWithin the concentration range of 0.01 to 100 µmol/L, Dex dose-dependently protected PC12 cells against glutamate-induced cytotoxicity. Treatment with 100 µmol/L Dex significantly increased the cell viability to (86.6∓2.2)% of that of the control cells (P<0.01) and decreased LDH release to 1.4∓0.1 folds of the control level (P<0.01). In PC12 cells exposed to glutamate, Dex pretreatment significantly reduced MDA content (P<0.01), enhanced SOD activity (P<0.01), inhibited ROS overproduction (P<0.01), reduced intracellular Calevel (P<0.01) and maintained a stable MMP (P<0.01).

CONCLUSIONDexmedetomidine can protect PC12 cells against glutamate-induced injury possibly in relation with its anti-oxidative activity, inhibitory effect on intracellular calcium overload and protective effect of the mitochondria.

Animals ; Apoptosis ; Calcium ; metabolism ; Cell Survival ; drug effects ; Dexmedetomidine ; pharmacology ; Glutamic Acid ; adverse effects ; Membrane Potential, Mitochondrial ; Mitochondria ; drug effects ; metabolism ; PC12 Cells ; Rats ; Reactive Oxygen Species ; metabolism

OBJECTIVETo investigate the cellular memory of previous high glucose exposure in rat islet cell line (INS-1) and explore the possible mechanism.

METHODSINS-1 cells were exposed to a high glucose (33.3 mmol/L) culture for 48 h followed by further culture in the presence of 11.1 mmol/L glucose in the culture medium for 3 or 5 days. The levels of bax and caspase-3 mRNA were measured by real-time PCR, the production of reactive oxygen species (ROS) was assayed using the dihydroethidium probe, and the cell viability was detected by MTT assay.

RESULTSHigh glucose exposure of the cells for 48 h resulted in significantly increased ROS production and bax and caspase-3 mRNA expressions and lowered cell viability (P<0.001). In cells cultured in 11.1 mmol/L glucose following previous high glucose exposure, the ROS production and bax and caspase-3 mRNA expressions still maintained the high levels (P<0.05) while the cell viability remained significantly lower than the control cells (P<0.001).

CONCLUSIONHigh glucose causes persistent changes in cell viability and apoptosis-related gene expressions even after recovery of normoglycemia, the mechanism of which is probably related to increased ROS production.

Animals ; Caspase 3 ; metabolism ; Cell Line ; Glucose ; adverse effects ; metabolism ; Insulin-Secreting Cells ; metabolism ; RNA, Messenger ; genetics ; Rats ; Reactive Oxygen Species ; metabolism ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo analyze the mechanisms of NAC on endoplasmic reticulum (ER) stress mediated cells apoptosis of HepG2 cells and to evaluate the potential role of NAC in the treatment of liver injury.

METHODSHepG2 cells were treated with H2O2 to make a model of oxidative ER stress mediated apoptosis. To evaluate the apoptosis, various methods such as MTT, DNA ladder, Western blot and flow cytometry were used. Then the optimal dosage and incubation time of NAC intervention in apoptosis were ascertained, and the differences between induction and intervention of apoptosis, including the percentage of apoptosis, the expression of apoptotic protein (GRP78, Caspase-12, PARP) and the production of reactive oxygen species (ROS) were compared.

RESULTSThe activity of the cells decreased by H2O2 (0, 1, 3, 5 mmol/L) treatments in a dose-dependent manner. The ratio of apoptotic cells increased (0.7%+/-0.5%, 26.4%+/-1.8%, 29.7%+/-1.2% and 51.2%+/-9.4%, respectively) as did the production of ROS (14.0%+/-0.5%, 95.2%+/-0.1%, 97.5%+/-0.2% and 98.3%+/-0.2%, respectively). The HepG2 cells showed typical morphologic change of ER stress 6 hr after they were treated with 3 mmol/L H2O2. ER stress mediated-apoptosis was confirmed by Western blot. NAC (10 mmol/L and 20 mmol/L) protected cells from apoptosis. Typical features of ER stress apoptosis were seen accompanied by diminishing the ratio of apoptotic cells from 29.7%+/-1.2% to 23.3%+/-4.7% and 14.3%+/-1.2%. The production of ROS also decreased from 97.5%+/-0.2% to 52.2%+/-0.8% and 51.2%+/-2.9%. The effect was related to the concentration: 20 mmol/L NAC was more effective than 10 mmol/L.

CONCLUSIONSAs an oxidizing agent, H2O2 may induce ROS in cells and induce oxidative stress, causing ER stress and apoptosis. NAC can inhibit the procession of ROS directly and prevent injuries to the hepatocytes.

Acetylcysteine ; pharmacology ; Apoptosis ; drug effects ; Endoplasmic Reticulum ; metabolism ; Hep G2 Cells ; Humans ; Hydrogen Peroxide ; Oxidative Stress ; Reactive Oxygen Species ; adverse effects

Fructose intake has increased dramatically over the past century and the upward trend has continued until recently. Increasing evidence suggests that the excessive intake of fructose induces salt-sensitive hypertension. While the underlying mechanism is complex, the kidney likely plays a major role. This review will highlight recent advances in the renal mechanisms of fructose-induced salt-sensitive hypertension, including (pro)renin receptor-dependent activation of intrarenal renin-angiotensin system, increased nephron Na transport activity via sodium/hydrogen exchanger 3 and Na/K/2Cl cotransporter, increased renal uric acid production, decreased renal nitric oxide production, and increased renal reactive oxygen species production, and suggest actions based on these mechanisms that have therapeutic implications.
Blood Pressure ; Fructose ; adverse effects ; Humans ; Hypertension ; chemically induced ; physiopathology ; Kidney ; physiopathology ; Nitric Oxide ; metabolism ; Reactive Oxygen Species ; metabolism ; Renin-Angiotensin System ; Sodium Chloride, Dietary ; adverse effects ; Sodium-Hydrogen Exchanger 3 ; metabolism ; Uric Acid ; metabolism

Fifty male Wistar rats were fed a standard chow diet or a high-fat (HF) diet, and different concentrations of green tea polyphenols (GTPs) (0.8, 1.6, and 3.2 g/L) were administered in the drinking water. We found that the malondialdehyde (MDA) level in the HF diet group was significantly higher than that in the control (CON) group (P<0.05). Decreased peroxisome proliferator-activated receptor (PPAR)-α and sirtuin 3 (SIRT3) expression, and increased manganese superoxide dismutase (MnSOD) acetylation levels were also detected in the HF diet group (P<0.05). GTP treatment upregulated SIRT3 and PPARα expression, increased the pparα mRNA level, reduced the MnSOD acetylation level, and decreased MDA production in rats fed a HF diet (P<0.05). No significant differences in total renal MnSOD and PPAR-γ coactivator-1α (PGC1-α) expression were detected. The reduced oxidative stress detected in kidney tissues after GTP treatment was partly due to the higher SIRT3 expression, which was likely mediated by PPARα.
Acetylation ; drug effects ; Animals ; Antioxidants ; pharmacology ; Diet, High-Fat ; adverse effects ; Gene Expression Regulation, Enzymologic ; drug effects ; Kidney ; drug effects ; metabolism ; Male ; Oxidative Stress ; drug effects ; Polyphenols ; pharmacology ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Sirtuin 3 ; metabolism ; Tea ; chemistry