This study aimed to investigate the neurotoxicity induced by trichloroacetic acid (TCA) and the possible protective mechanisms of boron (B). Mouse BV2 cells were treated with TCA (0, 0.39, 0.78, 1.56, 3.12, 6.25, or 12.5 mmol/L) and B (0, 7.8, 15.6, 31.25, 62.5, 125, 500, or 1,000 mmol/L) for 3 h and 24 h, respectively. Then, reactive oxygen species, and supernatant proinflammatory cytokine and protein levels were analyzed after 24 h of combined exposure. Beyond the dose-dependent decrease in the cellular viability, it clearly increased after B supplementation ( P < 0.05). Moreover, B decreased oxidative damage, and significantly down-regulated IL-6 levels and up-regulated TNF-β production ( P < 0.05). B also decreased apoptosis via the p53 pathway. The present findings indicated that TCA may induce oxidative damage, whereas B mitigates these adverse effects by decreasing cell apoptosis.
Animals ; Apoptosis ; Boron/toxicity* ; Mice ; Oxidative Stress ; Reactive Oxygen Species/metabolism* ; Trichloroacetic Acid/toxicity* ; Tumor Suppressor Protein p53/metabolism*

OBJECTIVETo study the effect of reactive oxygen species (ROS) during the leukemogenic process associated with exposure to benzene.

METHODSHL-60 was treated with 3 micromol/L benzoquinone (BQ). Generation of ROS in cells was measured by DCFH-DA method. For proliferation assays,cells were stained with alamar blue dye and counted.

RESULTSROS production and the proliferation of cell were all increased in BQ-treated cells (13.10 +/- 0.15, 185% +/- 30.00%) as compared with control cells (11.32 +/- 0.09, 100% +/- 0.00%) (P < 0.05); The addition of catalase just before BQ addition reduced ROS generation to basal levels and decreased the growth of cell (P < 0.05).

CONCLUSIONROS may play an important role in the process of proliferation of HL-60 cells induced by BQ.

Benzoquinones ; toxicity ; Cell Proliferation ; drug effects ; HL-60 Cells ; drug effects ; metabolism ; pathology ; Humans ; Reactive Oxygen Species ; metabolism

OBJECTIVETo investigate the cytotoxic effect of multi-walled carbon nanotubes (MWCNTs) on human liver L02 cells and its relevant mechanism.

METHODSMWCNTs, carboxyl modification MWCNTs (MWCNTs-COOH), and hydroxyl modification MWCNTs (MWCNTs-OH) were characterized by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The carbon nanotubes at concentrations of 12.5, 25, 50, 100, and 200 μg/ml were incubated with human liver L02 cells for 24, 48 and 72 hours, respectively. The cell viability was evaluated by water soluble tetrazolium salts assay and the intercellular reactive oxygen species induced by the carbon nanotubes were detected by 2', 7'-dichlorodihydrofluorescein diacetate method.

RESULTSTransmission electron microscope showed that the average outside diameters (10 to 20 nm) and the average length (10 to 30 μm) of the three MWCNTs were similar. Scanning electron microscope indicated that the three MWCNTs had a similar surface topography. X-ray photoelectron spectroscopy demonstrated that the MWCNTs-COOH and MWCNTs-OH had relatively high peak areas at 289 and 286ev, respectively,indicating that they have been modified by carboxyl and hydroxyl groups,respectively. Water soluble tetrazolium salts assay showed that the MWCNTs-COOH was less cytotoxic when compared to MWCNTs which demonstrated to be slightly more cytotoxic than MWCNTs-OH. The capability to induce increase in intracellular reactive oxygen species was in the following order: MWCNTs > MWCNTs-COOH > MWCNTs-OH.

CONCLUSIONSModification of MWCNTs with carboxyl group and hydroxyl group improves the biocompatibility of MWCNTs to some extents. MWCNTs-COOH has better compatibility than MWCNTs at the low concentration,and MWCNTs-OH showed better compatibility than MWCNTs after 48 hours. Different mechanisms may be involved in the interaction between cells and the MWCNTs with different chemical surfaces.

Cell Survival ; drug effects ; Cells, Cultured ; Hepatocytes ; drug effects ; metabolism ; Humans ; Nanotubes, Carbon ; chemistry ; toxicity ; Reactive Oxygen Species ; metabolism

OBJECTIVETo explore the effects of chronic exposure to trace chromium (VI) as a result of metal-on-metal hip arthroplasty on oxidative stress in mouse liver cells.

METHODSEighty NIH mice were randomly divided into 4 groups and subject to intraperitoneal injection of CrO(3) at the dose of 0, 5, 10 or 20 mg/kg every other day for 16 weeks. Five mice from each group were selected every 4 weeks for determining the content of chromium (VI) in the whole blood and the levels of reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), glutathione reductase (GR) activity, and glutamate cysteine ligase (GCL) expression in the liver cells. The ultrastructural changes of the liver cells were also observed using transmission electron microscopy.

RESULTSExposure to 5 and 10 mg/kg CrO(3) caused significantly increased blood chromium concentration and ROS level, which reached the peak level at 8 weeks and became stabilized, whereas at the dose of 20 mg/kg, CrO(3) exposure resulted in progressive, time-dependent increase of blood chromium concentration and ROS level. MDA showed no significant changes in the 4 groups. With the prolongation of the exposure time, GSH content and GR activity were decreased in these groups. In 5 and 10 mg/kg CrO(3) groups, GCL expression increased at each time point of measurement, but in 20 mg/kg group, GCL expression decreased gradually with a prolonged exposure. Transmission electron microscopy revealed apoptotic changes of the liver cells in 20 mg/kg group.

CONCLUSIONThe slow accumulation of trace chromium (VI) after metal-on-metal hip arthroplasty may cause oxidative stress and changes in the oxidative stress system in the liver cells.

Animals ; Apoptosis ; Chromium ; administration & dosage ; toxicity ; Environmental Exposure ; Glutathione ; metabolism ; Hepatocytes ; metabolism ; pathology ; Malondialdehyde ; metabolism ; Mice ; Oxidative Stress ; Reactive Oxygen Species ; metabolism ; Superoxide Dismutase ; metabolism ; Toxicity Tests, Chronic

Acetylcysteine ; pharmacology ; Antioxidants ; pharmacology ; Composite Resins ; toxicity ; Dental Materials ; toxicity ; Fibroblasts ; drug effects ; metabolism ; Gingiva ; cytology ; drug effects ; Humans ; Methacrylates ; toxicity ; Polyethylene Glycols ; toxicity ; Polymethacrylic Acids ; toxicity ; Polymethyl Methacrylate ; toxicity ; Reactive Oxygen Species ; metabolism ; Resins, Synthetic ; toxicity

OBJECTIVETo observe the effects of different sized titanium dioxide on reactive oxygen species (ROS) levels.

METHODSForty-eight healthy mice were divided into 3 groups randomly: control group (distilled water), 50 nm TiO₂ (5 g/kg) group and 120 nm TiO₂ (5 g/kg) group. The mice were exposed to distilled water or TiO₂ by a syringe via gastrointestinal tract in a minute. One week later, the mice were sacrificed and the liver, kidney and brain (cortex, hippocampus) were collected. The contents of Ti in the above tissues of mice were measured by ICP-MS. The ROS levels in the tissues were measured by flow cytometry.

RESULTSThere was no significant difference in organ coefficient between two exposure groups and control group (P > 0.05). The Ti contents in liver, kidney, cortex and hippocampus of two exposure groups were higher than those of control group (P < 0.05); The Ti contents of above four tissues in 50 nm TiO₂ group were higher than those in 120 nm group (P < 0.05). The ROS levels in liver, kidney and cortex cells of two exposure groups (273.2 ± 32.5, 160.2 ± 28.5, 74.9 ± 8.9; 159.4 ± 15.9, 64.4 ± 7.5, 41.2 ± 5.6) significantly increased, as compared with control group (74.9 ± 6.4, 24.9 ± 2.8, 32.8 ± 3.1) (P < 0.05). The ROS levels in hippocampus cells in 50 nm TiO₂ group were significantly higher than those in control group (P < 0.05). The ROS levels of above four tissues in 50 nm group were significantly higher than those in 120 nm TiO₂ group (P < 0.05).

CONCLUSIONAfter mice were exposed to 50 nm and 120 nm TiO₂ particles via gastrointestinal tract, Ti could be distributed into the liver, kidney and the brain tissues in mice, resulting in the enhanced ROS levels in liver, kidney, cortex and hippocampus cells. Moreover, the ROS levels induced by 50 nm TiO₂ particles are significantly higher than those induced by 120 nm TiO₂ particles.

Animals ; Lipid Peroxidation ; drug effects ; Male ; Mice ; Mice, Inbred Strains ; Particle Size ; Reactive Oxygen Species ; metabolism ; Titanium ; chemistry ; toxicity

OBJECTIVEThe aim of this study was to investigate the use of the lesion-specific endonucleases-modified comet assay for analysis of DNA oxidation in cell lines.

METHODSDNA breaks and oxidative damage were evaluated by normal alkaline and formamidopyrimidine-DNA-glycosylase (FPG) modified comet assays. Cytotoxicity were assessed by MTT method. The human bronchial epithelial cell (16HBE) were treated with benzo (a) pyrene (B(a)P), methyl methanesulfonate (MMS), colchicine (COL) and vincristine (VCR) respectively, and the dose is 20 µmol/L, 25 mg/ml, 5 mg/L and 0.5 mg/L for 24 h, respectively. Oxidative damage was also detected by levels of reactive oxygen species in treated cells.

RESULTSFour genotoxicants give higher cytotoxicity and no significant changes on parameters of comet assay treated by enzyme buffer. Cell survival rate were (59.69 ± 2.60) %, (54.33 ± 2.81) %, (53.11 ± 4.00) %, (51.43 ± 3.92) % in four groups, respectively. There was the direct DNA damage induced by test genotoxicants presented by tail length, Olive tail moment (TM) and tail DNA (%) in the comet assay. The presence of FPG in the assays increased DNA migration in treated groups when compared to those without it, and the difference was statistically significant which indicated that the clastogen and aneugen could induce oxidative damage in DNA strand. In the three parameters, the Olive TM was changed most obviously after genotoxicants treatment. In the contrast group, the Olive TM of B(a) P,MMS, COL,VCR in the contrast groups were 22.99 ± 17.33, 31.65 ± 18.86, 19.86 ± 9.56 and 17.02 ± 9.39, respectively, after dealing with the FPG, the Olive TM were 34.50 ± 17.29, 43.80 ± 10.06, 33.10 ± 12.38, 28.60 ± 10.53, increased by 58.94%, 38.48%, 66.86% and 68.21%, respectively (t value was 3.91, 3.89, 6.66 and 3.87, respectively, and all P < 0.05), and the correlation between Olive TM and reactive oxygen species was better than other parameters (r = 0.77, P < 0.05).

CONCLUSIONThis study indicates that FPG-comet assay appears more specific for detecting oxidative DNA damage induced by genotoxicants exposure, and the application of comet assay will be expanded. The endonuclease modified comet assay will be used widely in the toxicology and molecular epidemiology study.

Cell Line ; Comet Assay ; methods ; DNA Damage ; Endonucleases ; Humans ; Mutagens ; toxicity ; Oxidation-Reduction ; Oxidative Stress ; Reactive Oxygen Species ; metabolism

OBJECTIVEIn vitro model of hydrogen peroxide induced apoptosis of SW-480 cells was used to investigate the role of NF-kappaB in the pathogenesis of reactive oxygen species induced apoptosis of intestinal epithelial cells.

METHODSUltra-structural changes were observed. Apoptosis of SW-480 cell line was determined by Annexin-V and PI double-stained flow cytometry. Nuclear translocation of NF-kappaB was determined by anti-NF-kappaB polyclonal antibody and EB double-staining. NF-kappaB activity was studied by electrophoretic mobility shift assays. RT-PCR was performed to study expression of NF-kappaB mRNA.

RESULTSHydrogen peroxide led to apoptosis of SW-480 cells, condensed or semilunar chromatin even apoptotic bodies could be observed. Nuclear translocation of NF-kappaB, increase of NF-kappaB activity and expression of NF-kappaB mRNA were found simultaneously.

CONCLUSIONSEarly activation of NF-kappaB may be one of the mechanisms of apoptosis in intestinal epithelial cells by reactive oxygen species.

Apoptosis ; Humans ; Hydrogen Peroxide ; toxicity ; Intestinal Mucosa ; metabolism ; Microscopy, Confocal ; NF-kappa B ; metabolism ; Reactive Oxygen Species ; toxicity ; Tumor Cells, Cultured

This study investigated the conjoined cellular oxidative damage of human embryo kidney 293T (HEK293T) cells induced by cadmium chloride (CdCl(2)) and nanometer titanium dioxide (nano-TiO(2)). RT-PCR technique was used to detect the expressions of Heme oxygenase-1 (HO-1) and 8-oxoguanine DNA glycosylase (OGG1). The activities of superoxide dismutase (SOD) and catalase enzyme (CAT) and concentrations of reactive oxygen species (ROS) and maldondialdehyde (MDA) were measured by different approaches. The results showed that CdCl(2) and nano-TiO(2) at a low concentration of 0.75 total toxic unit (TU) exerted an additive effects on HO-1 gene expression, CAT activities and MDA concentrations. When the total TU was increased to 1 or 1.25 TU, the interaction was synergetic. Moreover, the mixture with high proportion of CdCl(2) produced an additive effect on the OGG1 gene expression, and the interaction was changed to be synergetic when the concentration of CdCl(2) was lower than or equal to that of nano-TiO(2). Synergetic effects of CdCl(2) and nano-TiO(2) on cellular oxidative damage of HEK293T cells were found as indicated by the changes in the SOD activities and ROS concentrations. It was concluded that CdCl(2) and nano-TiO(2) exerts synergistic effects on the cellular oxidative damage of HEK293T cells, and the sensitivity of these indicators of oxidative damage varies with the proportion of CdCl(2) and nano-TiO(2) in the mixture.
Cadmium Chloride ; toxicity ; Drug Synergism ; HEK293 Cells ; Humans ; Kidney ; cytology ; Nanoparticles ; Oxidative Stress ; drug effects ; Reactive Oxygen Species ; metabolism ; Superoxide Dismutase ; metabolism ; Titanium ; toxicity

OBJECTIVETo identify the role of reactive oxygen species (ROS) formation on cell death induced by Ent-11alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F) in HepG2 cells.

METHODMTT assay was used to determine the effect of 5F on proliferation of HepG2 cells, and apoptotic morphological changes were assessed using Hoechst/PI assay. To evaluate intracellular ROS levels, a GENMED kit was used. HepG2 cells were treated with 5F for 24 h or with 1 mmol x L(-1) GSH for 1 h prior to treatment with 5F for 24 h, then cytoplasmic mono- and oligonucleosomes were assessed with Cell Death Detection ELISA kit.

RESULTThe cytotoxicity of 5F on HepG2 cells was elevated with increasing 5F concentrations, as evidenced by the cell viability assay, and the apoptotic changes such as chromatin condensation were confirmed by Hoechst/PI staining. The decrease in ROS generation was observed in HepG2 cells following treatment with 5F. Cytoplasmic mono- and oligonucleosomes induced by 5F were not changed by decreasing basal level of ROS-mediated signaling with GSH. Further more, induction of ROS production by cisplatinum (CDDP) was canceled by treatment with 5F and 5F revealed a additive effect to cell killing by CDDP.

CONCLUSION5F can not only induce apoptosis through non-ROS-depandent pathway, and can abate oxidant stress.

Apoptosis ; drug effects ; Cell Death ; drug effects ; Diterpenes ; toxicity ; Drugs, Chinese Herbal ; toxicity ; Hep G2 Cells ; Humans ; Pteris ; chemistry ; Reactive Oxygen Species ; metabolism