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1.
The present study reports the protective effects of kolaviron, a Garcinia biflavonoid from the seeds of Garcinia kola widely consumed in some West African countries against oxidative damage to molecular targets ex-vivo and in vitro. Treatment with hydrogen peroxide (H2O2) at a concentration of 100 micromol/L increased the levels of DNA strand breaks and oxidized purine (formamidopyrimidine glycosylase (FPG) and pyrimidine (endonuclease III (ENDO III) sites) bases in both human lymphocytes and rat liver cells using alkaline single cell gel electrophoresis (the comet assay). Kolaviron was protective at concentrations between 30-90 micromol/L and decreased H2O2-induced DNA strand breaks and oxidized bases. Neither alpha-tocopherol nor curcumin decreased H2O2-induced DNA damage in this assay. In lymphocytes incubated with Fe3+/GSH, Fe3+ was reduced to Fe2+ by GSH initiating a free radical generating reaction which induced 11.7, 6.3, and 4.9 fold increase respectively in strand breaks, ENDO III and FPG sensitive sites compared with control levels. Deferoxamine (2 mmol/L), an established iron chelator significantly inhibited GSH/Fe3+-induced strand breaks and oxidized base damage. Similarly, kolaviron at 30 and 90 micromol/L significantly attenuated GSH/Fe3+-induced strand breaks as well as base oxidation. Kolaviron (100 mg/kg bw) administered to rats for one week protected rat liver cells against H2O2-induced formation of strand breaks, ENDO III, and FPG sensitive sites, Fe3+/EDTA/ascorbate-induced malondialdehyde formation and protein oxidation using gamma-glutamyl semialdehyde (GGS) and 2-amino-adipic semialdehyde (AAS) as biomarkers of oxidative damage to proteins. We suggest that kolaviron exhibits protective effects against oxidative damage to molecular targets via scavenging of free radicals and iron binding. Kolaviron may therefore be relevant in the chemoprevention of oxidant-induced genotoxicity and possibly human carcinogenesis.  相似文献   

2.
《Free radical research》2013,47(3):322-331
Abstract

Many potentially significant genetic variants related to oxidative stress have been identified and performance in endurance sports is a multi-factorial phenotype. Thus, it was decided to investigate the influences of the haptoglobin (Hp), MnSOD (Val9Ala), CAT (21A/T), GPX1 (Pro198Leu), ACE, glutathione S-transferases M1 (GSTM1) and T1 (GSTT1) genes' polymorphisms on the oxidative stress and damage suffered by human athletes (runners). Blood samples taken immediately after a race were submitted to genotyping, comet and TBARS assays, biochemical analyses of creatine kinase (CK), aspartate aminotransferase (AST) and alanine aminotransferase (ALT). MnSOD significantly influenced results of CK and a possible association between Hp1F-1S and Hp1S-2 genotypes with a superior TBARS values was found. Higher or lower TBARS and CK values or DNA damage also depended on the interaction between Hp and ACE or GST genotypes, indicating that MnSOD and Hp polymorphisms can be determining factors in performance, at least for runners.  相似文献   

3.
The role of selenium, a trace element in the human diet, has been extensively studied against cancer, immunity and infectious/inflammatory diseases. The purpose of the present study was to investigate the beneficial effect of ebselen, an organo-selenium compound, against cyclophosphamide-induced oxidative stress and DNA damage in mice. Malondialdehyde and total glutathione were estimated in the liver to detect the oxidative stress induced by cyclophosphamide. Standard and modified comet assays (the latter incorporated lesion-specific enzymes, formamidopyrimidine-DNA glycosylase and endonuclease-III) were used to detect the normal and oxidative stress-induced DNA damage by cyclophosphamide in the mouse bone marrow and the peripheral blood lymphocytes. In addition, a micronucleus assay capable of detecting DNA damage was also carried out in the mouse bone marrow and the peripheral blood reticulocytes induced by cyclophosphamide. The results confirm that pre-treatment with ebselen (2.5, 5 and 10 mg/kg) for 5 consecutive days decreased the oxidative stress induced by cyclophosphamide (100 mg/kg) based on the restoration in concentration of malondialdehyde and glutathione in the liver and decreased DNA damage and micronuclei count in the bone marrow and the peripheral blood. It is concluded that pre-treatment with ebselen attenuates cyclophosphamide-induced oxidative stress and the resultant DNA damage in mice.  相似文献   

4.
Depending on the analytical method employed estimates of background levels of base oxidation in human DNA vary over orders of magnitude. It is now realised that oxidation of guanine in vitro can result in serious overestimation of the nucleoside by HPLC (with electrochemical detection). We have modified procedures of isolation, hydrolysis and storage of DNA with the aim of eliminating this artefact. Vacuum- or freeze-drying, and dialysis, tend to encourage oxidation. We compare results obtained with HPLC and with the comet assay, which employs lesion-specific enzymes to introduce breaks in DNA at sites of oxidative damage. Although estimates of background levels of DNA oxidation using the comet assay are several-fold lower than the estimates by HPLC, both approaches have been used successfully to detect differences between human subjects or population groups that seem to relate to human disease and nutritional factors.  相似文献   

5.
Abstract

Dimethoate is one of the organophosphate insecticides widely used in agriculture throughout the world and is an inhibitor of cholinesterase in animals. The objective of the present study was to detect oxidative stress and DNA damage induced by dimethoate in the freshwater fish Channa punctatus (C. punctatus). The LC50-96 h value of technical grade dimethoate was estimated at 19.10 μg L-1 in a semi-static system and, on the basis of the LC50 value, three concentrations were determined. The fish were exposed to these concentrations of dimethoate for 96 h and samplings were done at 24 and 96 h for assessment of oxidative stress and DNA damage. After exposure to dimethoate, the level of superoxide dismutase declined while lipid peroxidation, glutathione, induction of micronucleus and DNA damage were increased in C. punctatus as the concentration and exposure time increased. Thus our results suggest that dimethoate induces genotoxic effects which invariably accompanied and correlated with oxidative stress.  相似文献   

6.
《Biomarkers》2013,18(8):587-595
Oxidative stress is a potentially important aetiological factor for many chronic diseases, including cardiovascular disease, neurodegenerative disease and cancer, yet studies often find inconsistent results. The associations between three of the most widely used biomarkers of oxidative stress, i.e. F2-isoprostanes for lipid peroxidation and 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxo-dG) and the comet assay with FPG for oxidative DNA damage, were compared in a sample of 135 healthy African-American and white adults. Modest associations were observed between F2-isoprostanes and the comet assay (r?=?0.22, p?=?0.01), but there were no significant correlations between 8-oxo-dG and the comet assay (r?=??0.09) or F2-IsoP (r?=??0.04). These results are informative for researchers seeking to compare results pertaining to oxidative stress across studies and/or assessment methods in healthy disease-free populations. The development and use of oxidative stress biomarkers is a promising field; however, additional validation studies are necessary to establish accuracy and comparability across oxidative stress biomarkers.  相似文献   

7.
Consumption of cruciferous vegetables may protect against colorectal cancer. Cruciferous vegetables are rich in a number of bioactive constituents including polyphenols, vitamins and glucosinolates. Before consumption, cruciferous vegetables often undergo some form of processing that reduces their content of bioactive constituents and may determine whether they exert protective effects. The aim of this study was to compare the ability of raw and blanched‐frozen broccoli to protect colonocytes against DNA damage, improve antioxidant status and induce xenobiotic metabolizing enzymes (XME). Fifteen Landrace × Large White male pigs were divided into five age‐matched and weight‐matched sets (79 days, SD 3, and 34·7 kg, SD 3·9, respectively). Each set consisted of siblings to minimize genetic variation. Within each set, pigs received a cereal‐based diet, unsupplemented (control) or supplemented with 600 g day?1 of raw or blanched‐frozen broccoli for 12 days. The consumption of raw broccoli caused a significant 27% increase in DNA damage in colonocytes (p = 0·03) relative to the control diet, whereas blanched‐frozen broccoli had no significant effect. Both broccoli diets had no significant effect on plasma antioxidant status or hepatic and colonic XME. This study is the first to report that the consumption of raw broccoli can damage DNA in porcine colonocytes. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

8.
Oxaliplatin is a third generation platinum (Pt) drug with a diaminocyclohexane (DACH) entity, which has recently obtained worldwide approval for the clinical treatment of colon cancer, and apparently operates by a different mechanism of action to the classical cisplatin or carboplatin. Introducing a novel dual mechanism of action is one approach in designing a new platinum-based anticancer agent, whereby an appropriate ligand, such as demethylcantharidin (DMC), is released from the parent compound to exert a cytotoxic effect, in addition to that of the DNA-alkylating function of the platinum moiety. To investigate the likelihood of a novel dual mechanism of anticancer action, demethylcantharidin-integrated Pt complexes: Pt(R,R-DACH)(DMC) with the same Pt-DACH moiety as oxaliplatin, and Pt(NH(3))(2)(DMC) akin to carboplatin; were studied for their ability to induce DNA damage in HCT116 colorectal cancer cells by an alkaline comet assay. The results showed that the DMC ligand released from the novel complexes caused additional DNA lesions when compared with oxaliplatin and carboplatin. The comet assay also revealed that the DNA-damaging behavior of cisplatin is characteristically different; and this study is the first to demonstrate the ability of DMC to induce DNA lesions, thus providing sufficient evidence to explain the superior antiproliferative effect of the novel DMC-integrated complexes.  相似文献   

9.
We used X-rays from a linear accelerator and from a low energy therapeutic source to calibrate the single cell gel electrophoresis (comet assay), a widely used method to measure DNA damage. γ-Rays from 60Co, with known efficiency in inducing DNA breakage, were used as reference. Human lymphocytes and one murine tumour cell line, F10-M3 cells, were irradiated under different experimental conditions. A similar relationship between radiation dose and induced DNA damage was obtained with γ- and X-rays. A calibration curve was constructed to convert the comet assay raw data into break frequency. The median levels of DNA breaks and oxidative damage in circulating lymphocytes from healthy volunteers were calculated to be 0.76 and 0.80 breaks/109 Da, respectively, (0.50 and 0.52 breaks/106 bp). The values of oxidative DNA damage were in the same order of magnitude as those found by others with HPLC methods.  相似文献   

10.
We used X-rays from a linear accelerator and from a low energy therapeutic source to calibrate the single cell gel electrophoresis (comet assay), a widely used method to measure DNA damage. γ-Rays from 60Co, with known efficiency in inducing DNA breakage, were used as reference. Human lymphocytes and one murine tumour cell line, F10-M3 cells, were irradiated under different experimental conditions. A similar relationship between radiation dose and induced DNA damage was obtained with γ- and X-rays. A calibration curve was constructed to convert the comet assay raw data into break frequency. The median levels of DNA breaks and oxidative damage in circulating lymphocytes from healthy volunteers were calculated to be 0.76 and 0.80 breaks/109 Da, respectively, (0.50 and 0.52 breaks/106 bp). The values of oxidative DNA damage were in the same order of magnitude as those found by others with HPLC methods.  相似文献   

11.
The relationships between DNA damage and oxidative stress in the digestive gland, gills and haemocytes of the freshwater bivalve Unio tumidus were investigated. Two markers of genotoxicity were measured: DNA breaks by means of the comet assay, and oxidative DNA lesions by means of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) measured using high-performance liquid chromatography (HPLC) coupled to electrochemical detection. Lipid peroxidation was evaluated by measuring malondialdehyde (MDA) tissue levels. Effects were studied after exposure of bivalves for 6 days to benzo[a]pyrene (B[a]P) (50 and 100 μg?l?1) and ferric iron (20 and 40 mg?l?1), applied alone or in combination. Lipid peroxidation in the digestive gland and gills resulted from exposure to Fe3+ or B[a]P whatever the concentrations tested. DNA oxidatively formed lesions were induced in the two tissues at a higher level after B[a]P exposure than after Fe3+ treatment. No significant dose–response relationship was found with the two compounds and no synergistic effect was observed between Fe3+ and B[a]P. The gills appeared less sensitive than the digestive gland to DNA lesions expressed as 8-oxodGuo and comet results. Good correlations were noted between 8-oxodGuo and comet. MDA and DNA damage did not correlate as well, although it was stronger in the digestive gland than in the gills. Production of mucus by the gills likely served to prevent lesions by reducing the bioavailability of the chemicals tested, which could explain that dose–effect relationships and synergistic effects were not observed.  相似文献   

12.
Iron, a key element in Fenton chemistry, causes oxygen-related toxicity to cells of most living organisms. Helicobacter pylori is a microaerophilic bacterium that infects human gastric mucosa and causes a series of gastric diseases. Exposure of H. pylori cells to air for 2 h elevated the level of free iron by about 4-fold as measured by electron paramagnetic resonance spectroscopy. H. pylori cells accumulated more free iron as they approached stationary phase growth, and they concomitantly suffered more DNA damage as indicated by DNA fragmentation analysis. Relationships between the intracellular free iron level, specific oxidative stress enzymes, and DNA damage were identified, and new roles for three oxidative stress-combating enzymes in H. pylori are proposed. Mutant cells defective in either catalase (KatA), in superoxide dismutase (SodB) or in alkyl hydroperoxide reductase (AhpC) were more sensitive to oxidative stress conditions; and they accumulated more free (toxic) iron; and they suffered more DNA fragmentation compared to wild type cells. A significant proportion of cells of sodB, ahpC, or katA mutant strains developed into the stress-induced coccoid form or lysed; they also contained significantly higher amounts of 8-oxo-guanine associated with their DNA, compared to wild type cells.  相似文献   

13.
许翠娅 《应用生态学报》2022,33(6):1679-1685
为研究对二甲苯对皱纹盘鲍肝胰腺的毒性作用,设置4个浓度(0.5、1.0、1.5和2.0 mg·L-1)和对照组,开展为期21 d的对二甲苯对皱纹盘鲍的亚慢性毒性试验,采用彗星试验技术进行皱纹盘鲍肝胰腺细胞DNA损伤分析,采用CASP分析软件对拖尾率、彗星尾长、彗尾DNA相对含量、Olive矩等损伤指标进行统计。结果表明: 与对照组相比,各染毒组皱纹盘鲍肝胰腺细胞DNA均受到损伤,且损伤程度存在显著性差异。随着染毒浓度的增加,肝胰腺细胞DNA受损程度加重,高浓度甚至可以引发细胞凋亡,呈现一定的剂量-损伤效应。中浓度对二甲苯短时间暴露即可对皱纹盘鲍肝胰腺细胞造成DNA损伤,随着暴露时间延长,细胞DNA受损程度加重,呈现一定的时间-损伤效应。但长时间暴露细胞DNA各损伤指标有所减小,这可能与细胞自身的DNA修复机制和生物体解毒系统的代谢机制有关。研究表明,对二甲苯可对皱纹盘鲍肝胰腺细胞产生氧化损伤,导致DNA断裂,高浓度的对二甲苯长时间暴露可导致其细胞凋亡。  相似文献   

14.
Purpose: The main goal of the present study was to determine DNA damage in pesticide-exposed greenhouse workers and pesticides non-exposed controls.

Materials and methods: The DNA damage was measured by alkaline comet assay method (pH?>?13) in 41 greenhouse workers and 45 non-exposed individuals as the control. Pesticide exposure was assessed by duration of working in the greenhouse and pesticide application in the greenhouse time. DNA damage was estimated by arbitrary unit and damage frequency.

Results: Arbitrary unit and damage frequency were consistently significantly higher in greenhouse workers than those of the controls (p?=?0.001). In terms of gender in greenhouse, DNA damage of female workers was significantly higher than those in male workers (p?<?0.05). We found significant correlation between DNA damage and working hours spent. Multiple linear regression analysis showed that working hours in the greenhouse as an indication of pesticide exposure were significantly associated with the DNA damage, which can be attributed to the genotoxic potential of the pesticide mixture.

Conclusions: The comet assay is sensitive to detect the damage exposed to chronic effect of pesticides in greenhouse workers. Significant DNA damage was obtained for the exposed group, which was associated with the pesticide exposure.  相似文献   


15.
Metformin (1-(diaminomethylidene)-3,3-dimethyl-guanidine), which is the most commonly prescribed oral antihyperglycaemic drug in the world, was reported to have several antioxidant properties such as the inhibition of advanced glycation end-products. In addition to its use in the treatment of diabetes, it has been suggested that metformin may be a promising anti-aging agent. The present work was aimed at assessing the possible protective effects of metformin against DNA-damage induction by oxidative stress in vitro. The effects of metformin were compared with those of N-acetylcysteine (NAC). For this purpose, peripheral blood lymphocytes from aged (n = 10) and young (n = 10) individuals were pre-incubated with various concentrations of metformin (10–50 μM), followed by incubation with 15 μM cumene hydroperoxide (CumOOH) for 48 h, under conditions of low oxidant level, which do not induce cell death. Protection against oxidative DNA damage was evaluated by use of the Comet assay and the cytokinesis-block micronucleus technique. Changes in the levels of malondialdehyde + 4-hydroxy-alkenals, an index of oxidative stress, were also measured in lymphocytes. At concentrations ranging from 10 μM to 50 μM, metformin did not protect the lymphocytes from DNA damage, while 50 μM NAC possessed an effective protective effect against CumOOH-induced DNA damage. Furthermore, NAC, but not metformin, inhibited DNA fragmentation induced by CumOOH. In contrast to the lack of protection against oxidative damage in lymphocyte cultures, metformin significantly protected the cells from lipid peroxidation in both age groups, although not as effective as NAC in preventing the peroxidative damage at the highest doses. Within the limitations of this study, the results indicate that pharmacological concentrations of metformin are unable to protect against DNA damage induced by a pro-oxidant stimulus in cultured human lymphocytes, despite its antioxidant properties.  相似文献   

16.
Oxidative stress, or the production of oxygen-centered free radicals, has been hypothesized as the major source of DNA damage that can lead to a variety of diseases including cancer. It is known that 8-hydroxy-deoxyguanosine (8-oxo-dG) is a useful biomarker of oxidative DNA damage. Our recent data showed that JWA, initially being cloned as a novel cell differentiation-associated gene, was also actively responsive to environmental stressors, such as heat-shock, oxidative stress and so on. In the present study, we have applied a modified comet assay and bacterial repair endonucleases system (endonuclease III and formamidopyrimidine glycosylase) to investigate if JWA is involved in hydrogen peroxide (H2O2)-induced DNA damage and repair in K562 and MCF-7 cells, and to demonstrate if the damage is associated with 8-oxo-dG. The results from the comet assay have shown that the average tail length and the percentage of the cells with DNA tails are greatly induced by H2O2 treatment and further significantly enhanced by the post-treatment of repair endonucleases. The H2O2-induced 8-oxo-dG formation in K562 and MCF-7 cells is dose-dependent. In addition, the data have clearly demonstrated that JWA gene expression is actively induced by H2O2 treatment in K562 and MCF-7 cells. The results suggest that JWA can be regulated by oxidative stress and is actively involved in the signal pathways of oxidative stress in the cells.  相似文献   

17.
Developmental competence of mammalian oocytes is compromised by currently available oocyte cryopreservation protocols. Experiments were designed to examine the effect of three cryopreservation protocols on the integrity of bovine oocyte DNA. In vitro matured bovine oocytes were cryopreserved either by slow cooling, vitrification in 0.25 ml straws, or in open pulled straws. After thawing/warming, recovered oocytes were immediately subjected to morphological evaluation. Morphologically intact oocytes underwent comet assay to detect cryoinjury at DNA level. All cryopreservation protocols resulted in significant morphological damage as well as DNA damage compared to unfrozen control. Among the morphologically intact oocytes, there was no difference among protocols in the number of oocytes displaying DNA damage. However, oocytes that had been cryopreserved by slow cooling or by vitrification in open pulled straws exhibited more damage than those vitrified in 0.25 ml straws in the extent of DNA damage. If we combine the number of oocytes with morphological damage and oocytes with DNA damage, oocytes cooled by slow cooling resulted in the most damage. This experiment demonstrated that oocyte DNA is a target of cryoinjury and different protocols result in different degrees of damage.  相似文献   

18.
Fluoride (F) and sulfur dioxide (SO2) are the two common environmental contaminants that are associated with neurotoxicity. The present study was conducted to explore individual and combined exposure effects of F and SO2 on histological alteration and DNA damage in rat brain. For this, male Wistar albino rats were exposed to sodium fluoride (100 mg/L NaF) and sulfur dioxide (39.3 mg/m3) individually and in combination for 8 weeks. Histological alteration in brain is evaluated by hematoxylin–eosin staining, showed shrunken neurons, darkly stained small nucleus and decreased cell numbers in F and SO2 exposed groups. The effect of F and SO2 on DNA damage was assessed by comet assay. The results showed an increase in ratio of tailing and tail length in F or/and SO2 administered rats. In addition, the proportion of grade II and III were also increased in individual and combined exposed groups. Compared with the individual exposure, the proportion the grade III was significantly high in combined exposure, suggesting a synergistic effect of F and SO2. These results indicate that the brain was more susceptible to the toxic effects of F and SO2. And combined exposure to these pollutants can lead more pronounced toxic effects on brain.  相似文献   

19.
徐池  陈剑东  徐莉  胡锋  李辉信 《生态学杂志》2012,31(7):1791-1797
为研究Cu2+对驯化蚯蚓的损伤影响,将赤子爱胜蚓(Eisenia fetida)在非致死浓度(100mgCu2+·kg-1)下驯化培养2周,以未驯化的蚯蚓为对照,测定Cu2+对驯化及未驯化蚯蚓的急性毒性,并通过彗星试验(cometassay)观察铜胁迫下(400mg·kg-1)驯化后蚯蚓基因损伤的动态变化。结果显示:14d时,Cu2+对驯化蚯蚓和未驯化蚯蚓的半致死浓度(LC50)分别为321.83~542.45和230.83~342.91mg·kg-1,驯化后蚯蚓的存活率得到显著提高。彗星试验结果表示:蚯蚓体腔细胞的尾长、尾部DNA含量以及尾矩呈非正态分布,在11和14d时,驯化后的蚯蚓基因损伤程度明显比未驯化蚯蚓低。彗星试验是检测Cu2+对蚯蚓活体基因损伤的有效手段,蚯蚓体的DNA损伤可以作为指示重金属污染物影响的生物标志物。  相似文献   

20.
The purpose of this study was to investigate the effect of Zn (zinc) concentration on CCs (cumulus cells) during in vitro maturation. For this purpose, DNA integrity of CCs by addition of different Zn concentrations [0 (control); 0.7 μg/ml (Zn1); 1.1 μg/ml (Zn2) and 1.5 μg/ml (Zn3)] to the culture medium was evaluated by comet assay. In addition, early apoptosis was analysed by annexin staining assay. CCs treated with Zn showed a significant decrease in the DNA damage in a dose‐dependent manner. Comet assay analysed for TM (tail moment) was significantly higher in cells cultured without Zn (control, P<0.01) with respect to cells treated with Zn (control: 5.24±16.05; Zn1: 1.13±5.31; Zn2: 0.10±0.36; Zn3: 0.017±0.06). All treatments were statistically different from the control (P=0.014 for Zn1; P<0.01 for Zn2 and Zn3). The frequency of apoptotic cells was higher in the control group (control: 0.142±0.07; Zn1: 0.109±0.0328; Zn2:0.102±0.013; Zn3: 0.0577±0.019). Statistical differences were found between control and Zn1 (P=0.0308), control and Zn2 (P=0.0077), control and Zn3 (P<0.0001), Zn1 and Zn3 (P<0.001) and Zn2 and Zn3 (P=0.0004). No differences were found between Zn1 and Zn2. In conclusion, low Zn concentrations increase DNA damage and apoptosis in CCs cultured in vitro. However, adequate Zn concentrations ‘protect’ the integrity of DNA molecule and diminish the percentage of apoptotic CC.  相似文献   

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