Morphological transformation by 8-hydroxy-2'-deoxyguanosine in Syrian hamster embryo (SHE) cells.

8-Hydroxy-2'-deoxyguanosine (OH8dG) is one of the most prevalent oxidative DNA modifications found in eukaryotic cells. Previous studies have suggested an association between OH8dG formation and carcinogenesis. However, it is unclear whether OH8dG formation results in the necessary genotoxic events for cancer development. In the present study, the formation of OH8dG and its ability to transform Syrian hamster embryo (SHE) cells was examined. Methylene blue, a photosensitizer that in the presence of light can generate singlet oxygen by a type II mechanism, was used to produce oxidative DNA damage (predominantly OH8dG) in SHE cells. Photoactivated methylene blue produced a dose-dependent increase in OH8dG as well as a dose-dependent increase in morphological transformation in SHE cells. SHE cells transfected with DNA that contained increasing concentrations of OH8dG displayed a dose-dependent increase in morphological transformation. Treatment with beta-carotene (a singlet oxygen quencher) inhibited both the formation of OH8dG and the induction of morphological transformation in photoactivated methylene blue-treated SHE cells. These results suggest that formation of OH8dG can induce morphological transformation and provide further support for a role of OH8dG formation in the carcinogenesis process.     

Mechanisms for the induction of oxidative stress in Syrian hamster embryo cells by acrylonitrile.

Chronic administration of acrylonitrile to rats resulted in an increase in the incidence of glial neoplasms of the brain. Recent studies have shown that acrylonitrile induces oxidative stress in rat brain and cultured rat glial cells. Acrylonitrile also induces morphological transformation concomitant with an increase in the formation of oxidized DNA in Syrian Hamster Embryo (SHE) cells in a dose-dependent manner. The mechanism for the induction of oxidative stress in SHE cells remains unresolved. The present study examined the effects of acrylonitrile on enzymatic and nonenzymatic antioxidants in SHE cells. SHE cells were treated with subcytolethal doses of acrylonitrile (0, 25, 50, and 75 microg/ml) for 4, 24, and 48 h. Acrylonitrile (50 microg/ml and 75 microg/ml) increased the amount of reactive oxygen species in SHE cells at all time points. Glutathione (GSH) was depleted and catalase and superoxide dismutase activities were significantly decreased in SHE cells after 4 h of treatment. The inhibition of these antioxidants was temporal, returning to control values or higher after 24 and 48 h. Xanthine oxidase activity was increased following 24 and 48 h treatment with acrylonitrile. 1-aminobenzotriazole, a suicidal P450 enzyme inhibitor, attenuated the effects of acrylonitrile on catalase and xanthine oxidase in SHE cells, suggesting that P450 metabolism is required for acrylonitrile to produce its effects on these enzymes. Additional studies showed that in the absence of metabolic sources acrylonitrile had no effect on either catalase or superoxide dismutase activity. These results suggest that the induction of oxidative stress by acrylonitrile involves a temporal decrease in antioxidants and increase in xanthine oxidase activity that is mediated by oxidative metabolism of acrylonitrile.     

Morphological cell transformation of Syrian hamster embryo (SHE) cells by the cyanotoxin, cylindrospermopsin

Cylindrospermopsin (CYN) is a cyanotoxin which has been implicated in human intoxication and animal mortality. Genotoxic activity of this hepatotoxin is known but its carcinogenic activity remains to be elucidated. In this work, CYN was assessed for its cell-transforming activity using the Syrian hamster embryo (SHE) cell transformation assay. This in vitro assay is used to evaluate the carcinogenic potential of chemical, physical and biological agents in SHE cells, which are primary, normal, diploid, genetically stable and capable of metabolic activation. We demonstrated that CYN induced a significant increase in morphological cell transformation in SHE cells following a 7-day continuous treatment in the range of non-cytotoxic concentrations 1 × 10⁻⁷-1 × 10⁻² ng/mL.     

Assessment of oxidative stress induced by gold nanorods following intra-tracheal instillation in rats

Gold nanorods (GNRs) are used for their wide variety of applications in various industries. There is a little availability of data related to toxicity and ecological implications of these GNRs. The study evaluated the oxidative stress induction following intra-tracheal instillation of 1 and 5?mg/kg b.w. doses of 10 and 25?nm GNRs by estimating various oxidative stress markers including lipid peroxidation (malondialdehyde; MDA), glutathione (GSH), superoxide dismutase (SOD), catalase and total antioxidant capacity (TAC) after 1?day, 1?week, 1?month, and 3?months post exposure periods. The results have shown increased MDA levels and decreased GSH levels following 1?day and 1?week post exposure periods, indicating induction of oxidative stress. Also, the SOD, catalase and TAC levels were significantly decreased following exposure of both 10 and 25?nm GNRs after 1?day and 1?week after exposures, indicating the inhibition of antioxidant defense mechanisms. Moreover, the 10?nm GNRs at 5?mg/kg dose displayed greater changes in all the estimated parameters, representing dose and size based induction of oxidative stress by GNRs. In contrast, a little change was observed during 1?month and 3?months post exposure periods, may be due to recovery. Finally, the GNRs induced dose-size-dependent oxidative stress induction by various oxidative stress markers following intra-tracheal instillation in rats.     

Mechanisms of 2-butoxyethanol carcinogenicity: studies on Syrian Hamster Embryo (SHE) cell transformation.

Previous studies showed that 2-butoxyethanol increased liver tumors in B6C3F1 mice following chronic exposure. While the mechanism of 2-butoxyethanol-induced liver carcinogenicity has not been defined, 2-butoxyethanol has been shown to induce hemolysis in rodents via 2-butoxyacetic acid, the major metabolite of 2-butoxyethanol. This toxic effect, coupled with the observation that continued treatment with 2-butoxyethanol results in hemosiderin deposition in the liver, has led to our hypothesis that liver carcinogenicity by 2-butoxyethnaol is mediated via oxidative stress (iron catalyzed) and Kupffer cell activation. The present study used Syrian Hamster Embryo (SHE) cell transformation, a surrogate in vitro model for carcinogenesis in vivo, to examine whether 2-butoxyethanol, 2-butoxyacetic acid, or iron (ferrous sulfate) produced cell transformation. SHE cells were treated with either 2-butoxyethanol (0.5-20 mM), 2-butoxyacetic acid (0.5-20 mM), or ferrous sulfate (0.5-75 microg/ml) for 7 days. 2-Butoxyethanol and 2-butoxyacetic acid did not induce cellular transformation. In contrast, treatment with ferrous sulfate (2.5 and 5.0 microg/ml) increased morphological transformation. Cotreatment of ferrous sulfate with the antioxidants alpha-tocopherol (vitamin E) or (-)-epigallocatechin-3-gallate (EGCG) prevented ferrous sulfate-induced transformation, suggesting the involvement of oxidative stress in SHE cell transformation. The level of oxidative DNA damage (OH8dG) increased following ferrous sulfate treatment in SHE cells; additionally, using single cell gel electrophoresis (comet assay), ferrous sulfate treatment produced an increase in DNA damage. Both DNA lesions were decreased by cotreatment of ferrous sulfate with antioxidants. These data support our proposal that iron, produced indirectly through hemolysis, and not 2-butoxyethanol or its metabolite 2-butoxyacetic acid, is responsible for the observed carcinogenicity of 2-butoxyethanol.     

Discrimination of a transformation phenotype in Syrian golden hamster embryo (SHE) cells using ATR-FTIR spectroscopy

Primary Syrian hamster embryo (SHE) cells might be used to assess morphological transformation following treatment with chemical carcinogens. We employed attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy to interrogate SHE colonies, as complex biomolecules absorb in the mid-infrared (IR; λ = 2–20 μm) giving vibrational spectra associated with structure and function. Early-passage SHE cells were cultured (pH 6.7) in the presence or absence of benzo[a]pyrene (B[a]P; 5.0 μg/ml). Unstained colonies were applied to an ATR crystal, and vibrational spectra were obtained in the ATR mode using a Bruker Vector 22 FTIR spectrometer with Helios ATR attachment. These were individually baseline-corrected and normalised. Spectra were then analysed using principal component analysis (PCA) plus linear discriminant analysis (LDA). PCA was used to reduce the dataset dimensions before LDA was employed to reveal clustering. This determined whether wavenumber–absorbance relationships expressed as single points (scores) in ‘hyperspace’ might on the basis of multivariate distance reveal biophysical differences associated with morphologies in vehicle control (non-transformed or transformed) or carcinogen-treated (non-transformed or transformed) cells. Retrospectively designated SHE colonies (following staining and microscopic analysis) clustered according to whether they were vehicle control (non-transformed), B[a]P-treated (non-transformed) or transformed (control and B[a]P-treated). Scores plots pointed to a B[a]P-treated phenotype and derived loadings plots highlighted distinguishing markers in control transformed vs. B[a]P-treated transformed; these were mostly associated with Amide I, Amide II and phosphate stretching (asymmetric and symmetric) vibrations. Combined application of ATR-FTIR spectroscopy and unsupervised (PCA)/supervised (LDA) may be a novel approach to scoring SHE colonies for morphological transformation.     

Morphological transformation of Syrian hamster embryo fibroblasts by the anabolic agent trenbolone

Trenbolone (TBOH), a synthetic androgen used as an anabolic agent in livestock, has been tested for mutagenicity in the Salmonella assay, for covalent DNA-binding in vitro, for induction of unscheduled DNA synthesis in HeLa cells and Syrian hamster embryo (SHE) fibroblasts and for morphological transformation of SHE cells. While TBOH gave negative results in the assays for mutagenicity and DNA damage, it was clearly capable of transforming SHE cells in culture. The natural androgen testosterone did not transform these cells. Thus, TBOH appears to be a substance which can transform cells independent of its hormonal action and without grossly damaging DNA.Abbreviations Used TBOH 17-hydroxy-4,9,11-androstatrien-3-one - DES diethylstilbestrol, E-3,4-di(p-hydroxyphenyl)hex-3-ene - DMSO dimethylsulfoxide - HRP horseradish peroxidase - LSC liquid scintillation counting - UDS unscheduled DNA synthesis - SHE Syrian hamster embryo - PBS phosphate-buffered saline pH 7.4 (0.14 M NaCl:3 mM KCL:8 mM Na₂HPO₄:1 mM KH₂PO₄) The results of this study have been reported in preliminary form at the Third Symposium of the Section of Experimental Cancer Research of the German Cancer Society, Heidelberg, March 6–8, 1985     

Acrylamide-induced cellular transformation.

Acrylamide is a monomer of polyacrylamide, whose products are used in biochemistry, the manufacture of paper, water treatment, and as a soil stabilizer. While polymeric acrylamide is nontoxic, the monomer can cause several toxic effects and has the potential for human occupational exposure. While acrylamide is not mutagenic in prokaryotic mutagenesis assays, chronic acrylamide treatment in rodents has been shown to produce tumors in both rats and mice. The mechanism for the induction of tumors by acrylamide is not known. In the present study, we examined the possibility that acrylamide might induce cellular transformation, using Syrian hamster embryo (SHE) cell morphological transformation as well as potential mechanisms for the cellular transformation. Results showed that treatment with 0.5 mM and higher concentrations of acrylamide continuously for 7 days induced morphological transformation. Cotreatment with acrylamide and N-acetyl-L-cysteine (NAC), a sulfhydryl group donor, resulted in the reduction of acrylamide-induced morphological transformation in SHE cells. Cotreatment with 1-aminobenzotriazole (ABT), a nonspecific P450 inhibitor, and acrylamide produced no change in morphological transformation when compared to acrylamide treatment only. Cotreatment with acrylamide and DL-buthionone-[S,R]-sulfoximine (BSO), a selective inhibitor of gamma-glutamylcysteine synthetase, increased the percent of morphologically transformed colonies compared to acrylamide treatment alone. Acrylamide reduced GSH levels in SHE cells, and cotreatment with acrylamide and NAC prevented the acrylamide-induced reduction of GSH. BSO treatment with acrylamide enhanced the depletion of GSH. These results suggest that acrylamide itself, but not oxidative P450 metabolites of acrylamide appear to be involved in acrylamide-induced cellular transformation and that cellular thiol status (possibly GSH) is involved in acrylamide-induced morphological transformation.     

Aluminium oxide nanoparticles induced morphological changes,cytotoxicity and oxidative stress in Chinook salmon (CHSE‐214) cells

Aluminium oxide nanoparticles (Al₂O₃ NPs) are increasingly used in diverse applications that has raised concern about their safety. Recent studies suggested that Al₂O₃ NPs induced oxidative stress may be the cause of toxicity in algae, Ceriodaphnia dubia, Caenorhabditis elegans and Danio rerio. However, there is paucity on the toxicity of Al₂O₃ NPs on fish cell lines. The current study was aimed to investigate Al₂O₃ NPs induced cytotoxicity, oxidative stress and morphological abnormality of Chinnok salmon cells (CHSE‐214). A dose‐dependent decline in cell viability was observed in CHSE‐214 cells exposed to Al₂O₃ NPs. Oxidative stress induced by Al₂O₃ NPs in CHSE‐214 cells has resulted in the significant reduction of superoxide dismutase, catalase and glutathione in a dose‐dependent manner. However, a significant increase in glutathione sulfo‐transferase and lipid peroxidation was observed in CHSE‐214 cells exposed to Al₂O₃ NPs in a dose‐dependent manner. Significant morphological changes in CHSE‐214 cells were observed when exposed to Al₂O₃ NPs at 6, 12 and 24 h. The cells started to detach and appear spherical at 6 h followed by loss of cellular contents resulting in the shrinking of the cells. At 24 h, the cells started to disintegrate and resulted in cell death. Our data demonstrate that Al₂O₃ NPs induce cytotoxicity and oxidative stress in a dose‐dependent manner in CHSE‐214 cells. Thus, our current work may serve as a base‐line study for future evaluation of toxicity studies using CHSE‐214 cells. Copyright © 2015 John Wiley & Sons, Ltd.     

间歇低氧合并肺气肿大鼠模型肝脏氧化应激及凝血功能的研究

目的建立肺气肿合并间歇低氧(IH)的重叠综合征(OS)大鼠模型,探讨OS大鼠肝脏炎性损伤及其凝血功能的变化。方法将60只雄性Wistar大鼠随机分成正常组(A组)、IH组(B组)、肺气肿组(C组)和IH合并肺气肿组(D组)。通过对大鼠进行16周的熏烟暴露造成大鼠肺气肿;从13周开始,同时施加程控预制的间歇低氧/再氧合(IH/ROX)处理对大鼠进行IH暴露4周。暴露结束后取各组大鼠肺和肝脏组织于光镜下观察并计算肝脏炎性损伤病理评分。取肝组织匀浆采用ELISA方法测定其超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性和丙二醛(MDA)浓度。检测血浆纤维蛋白原(FIB),血浆因子FⅧ促凝活性(FⅧ:C)、血管性血友病因子抗原(v WF:Ag)和抗凝血酶活性(AT:A)水平。结果 D组肝脏炎性损伤病理评分和凝血因子FIB、FⅧ:C、v WF:Ag水平均高于A、B、C组,而SOD和CAT活性以及AT:A水平低于其他3组(均P<0.05)。FIB、v WF:Ag、FⅧ:C、AT:A与SOD呈明显相关(r分别为-0.905、-0.941、-0.946和0.817,均P<0.01)。结论 OS动物模型下IH和肺气肿在导致氧化应激和高凝状态上具有一定叠加效应,可引起更强的肝脏炎症反应和血栓前状态。     

Indium chloride‐induced micronuclei via reactive oxygen species in Chinese hamster lung fibroblast V79 cells

We study the cytotoxicity of indium chloride (InCl₃) in Chinese hamster lung fibroblasts, the V79 cells, using MTT assay. The results showed that InCl₃ did not induce significant cytotoxicity at various concentrations tested. In addition, the frequency of micronuclei (MN) was assayed to evaluate the genotoxic effects of InCl₃ in V79 cells. InCl₃ at concentrations ranged 0.1–1 μM significantly increased MN frequency in a concentration‐dependent manner. Both catalase and superoxide dismutase at concentrations of 75 and 150 μg/mL significantly inhibited InCl₃‐induced MN. Similarly, Germanium oxide (GeO₂) and dimercaprol expressed antigenotoxic effects. From these findings, it is concluded that InCl₃ is a potent genotoxic chemical, which may be mediated partly by inducing oxidative stress. The significance of this study shows that the workers in the semiconductor factories should be cautious in exposing to the hazardous genotoxic InCl_3. © 2011 Wiley Periodicals, Inc. Environ Toxicol 28: 595–600, 2013.     

Phenolphthalein and bisacodyl: assessment of genotoxic and carcinogenic responses in heterozygous p53 (+/-) mice and syrian hamster embryo (SHE) assay.

Phenolphthalein (800 and 2400 mg/kg/day by gavage and 2400 mg/kg/day by diet) and bisacodyl (800-500, 4000-2000, and 8000 mg/kg/day by gavage) were administered to 15 male and 15 female and 20 male and 20 female p53(+/-) mice respectively for 26 weeks to investigate the potential carcinogenicity of each compound. Toxicokinetic analyses confirmed systemic exposure. p-Cresidine was administered by gavage (400 mg/kg/day) and served as the positive control agent in each study. Dietary phenolphthalein reduced survival in both sexes and early deaths were attributed to thymic lymphoma. No bisacodyl-related neoplasms were observed. Regardless of route of administration to p53(+/-) mice, phenolphthalein but not bisacodyl was unequivocally genotoxic, causing increased micronuclei in polychromatic erythrocytes. In the Syrian hamster embryo (SHE) cell transformation assay, phenolphthalein caused increases in morphologically transformed colonies, thereby corroborating NTP's earlier reports, showing phenolophthalein has potential carcinogenic activity. Bisacodyl was negative in the SHE assay. Results of these experiments confirm an earlier demonstration that dietary phenolphthalein causes thymic lymphoma in p53(+/-) mice and show that (1) phenolphthalein causes qualitatively identical results in this transgenic model regardless of route of oral administration, (2) phenolphthalein shows evidence of micronucleus induction in p53(+/-) mice for up to 26 weeks, (3) phenolphthalein induced transformations in the in vitro SHE assay, and (4) bisacodyl in p53(+/-) mice induces neither drug-related neoplasm, nor micronuclei in polychromatic erythrocytes, and did not induce transformations in the in vitro SHE assay.     

The testing of chemicals in the Syrian hamster embryo (SHE) cell transformation assay for assessment of carcinogenic potential.

The Syrian hamster embryo (SHE) cell transformation assay was used to test 28 chemical substances for their ability to induce morphologically transformed colonies. The purpose was to determine how well the assay method could be transferred from an experienced laboratory by including 18 chemicals previously evaluated and 10 new chemicals. Technical training was obtained in the experienced lab prior to testing. The assay was conducted at pH 6.7, a treatment period of 7 days was used, and single experiments were performed for each chemical. With this limited testing, 78% concordance with rodent bioassay results was obtained, and this high concordance would have increased if small, but statistically negative responses from single trials were overturned by positive data from repeat trials. Similarly, the results were highly concordant (90%) with the experienced lab results; only 2 chemical evaluations were discordant, and the use of repeat experiments would likely have eliminated these apparent disagreements. Thus, with appropriate training, the pH 6.7 SHE assay was successfully and reliably transferred.     

Cytotoxic and transforming effects of silica particles with different surface properties in Syrian hamster embryo (SHE) cells.

Several crystalline and amorphous silica dusts (two quartz of natural origin, one cristobalite of natural and two of biogenic origin, three amorphous diatomite earths and one pyrogenic amorphous silica) were studied in the SHE cell transformation assay, in order to compare their cytotoxic and transforming potencies and examine the role of the structure and of the state of the surface on these effects. Some samples were modified by grinding, etching and heating with the aim of establishing relationships between single surface properties and biological responses. The results showed that some quartz and cristobalite dusts (crystalline) as well as the diatomaceous earths (amorphous), but not the pyrogenic amorphous silica, were cytotoxic and induced morphological transformation of SHE cells in a concentration-dependent manner. The ranking in cytotoxicity was different from that in transforming potency, suggesting two separate molecular mechanisms for the two effects. The cytotoxic and transforming potencies were different from one dust to another, even among the same structural silicas. The type of crystalline structure (quartz vs cristobalite) and the crystalline vs biogenic amorphous form did not correlate with cytotoxic or transforming potency of silica dusts. Comparison of cellular effects induced by original and surface modified samples revealed that several surface functionalities modulate cytotoxic and transforming potencies. The cytotoxic effects appeared to be related to the distribution and abundance of silanol groups and to the presence of trace amounts of iron on the silica surface. Silica particles with fractured surfaces and/or iron-active sites, able to generate reactive oxygen species, induced SHE cell transformation. The results show that the activity of silica at the cellular level is sensitive to the composition and structure of surface functionalities and confirm that the biological response to silica is a surface originated phenomenon.     

Effects of perindopril and hydrochlorothiazide on selected indices of oxidative stress in the blood of elderly patients with essential hypertension

1. The aim of the present study was to determine the effect of hypotensive therapy with a diuretic (hydrochlorothiazide) and an angiotensin-converting enzyme inhibitor (perindopril) on selected oxidative stress parameters in the blood of elderly patients with essential hypertension. 2. Studies were performed in 45 elderly patients with essential hypertension at baseline and after the 45th day of perindopril (n = 25) or hydrochlorothiazide (n = 20) therapy, as well as in 25 young and 25 elderly normotensive subjects. The following parameters were measured: systolic and diastolic blood pressure, nitric oxide (NO), carbonyl groups and malondialdehyde (MDA) concentrations, as well as the activity of ceruloplasmin (Cp) oxidase, Cu-Zn superoxide dismutase (SOD-1) and catalase (CAT). 3. The activity of SOD-1 and NO levels were reduced with age. 4. Compared with elderly controls, hypertensive subjects showed increases in baseline MDA, carbonyl group concentrations and Cp oxidase activity and decreases in NO levels and SOD-1 and CAT activities. 5. Treatment with perindopril, but not hydrochlorothiazide, resulted in significant increases in SOD-1 and CAT activities and decreases in MDA concentration and Cp oxidase activity. Both therapies decreased the level of carbonyl groups and increased NO levels. 6. Angiotensin-converting enzyme inhibitor therapy has significant anti-oxidant effects that may be important in the treatment of elderly patients with essential hypertension.     

Study of ochratoxin A (OTA)-induced oxidative stress markers in broiler chicks

The current study was designed to investigate the effects of ochratoxin A (OTA) on the oxidative stress in day-old broiler chicks. A total of 60-day-old broiler chicks were divided into four equal groups A–D. Group A was control, groups B–D were administered with different levels of OTA (1.6, 3.2 and 6.4?mg/kg of feed), respectively, for 10?days from day one of their age. Superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant status of blood plasma, RBCs hemolysate and supernatant of tissue homogenates (liver, kidney and muscles) were estimated in all groups on days 11 and 31 in order to determine the oxidative stress in chicks. The results revealed a significant dose-dependent decrease in the SOD, GPx and TAS levels in all OTA-fed groups. It was found persistent even after 21?days of withdrawal of toxin-contaminated feed in all tissues except RBCs hemolysate. Present study described the OTA-induced oxidative stress as indicated by the low levels of SOD, GPx and TAS in different biological samples of broiler chicks.     

Evaluation of oxidative stress induction in rats following exposure to silver nanorods

The study investigated the oxidative stress induction by the 10 and 25?nm silver nanorods (SNRs) following intra-tracheal instillation in rats after 1?day, 1 week, 1 month and 3 months post instillation periods at 1 and 5?mg/kg b.w. doses. The blood was withdrawn by retro orbital plexus method after exposure periods and different oxidative stress markers were estimated. The results showed that the both sizes of SNRs induced increased levels of malondialdehyde (MDA) and depleted glutathione (GSH) levels after 1?day and 1 week post exposure periods. The 10 and 25?nm SNRs at both doses displayed that significantly reduced levels of superoxide dismutase (SOD) and catalase following 1?day and 1 week post exposure periods. Also, the results have shown that decrease in total antioxidant capacity (TAC) of both sizes of SNRs significantly following 1?day and 1 week post exposure periods, indicating the oxidative stress induction by SNRs. In spite, there were no significant changes in oxidative stress markers following 1 month and 3 months post exposure periods may be due to recovery. The increased levels of MDA and decreased levels of GSH, SOD, catalase and TAC activity are strongly associated to ROS production and lipid peroxidation, suggesting the induction of oxidative stress in rats. The 10?nm SNRs at 5?mg/kg b.w. dose exposures in rats have shown greater changes in all oxidative stress parameters, indicating the greater induction of oxidative stress when compared with the 25?nm SNRs, representing the size–dose-dependent induction of oxidative stress of SNRs.     

Non-genotoxicity of acrylic acid and n-butyl acrylate in a mammalian cell system (SHE cells)

Acrylic acid (AA), ethyl acrylate (EA) and n-butyl acrylate (BA) are widely used in the production of plastics, coatings and acrylic fibres. Occupational exposure occurs primarily via inhalation and/or skin contact.In chronic inhalation experiments EA and BA did not induce neoplastic changes in rats and mice (Klimisch and Reininghaus 1984; Miller et al. 1985). Additional investigations showed that AA and BA were not carcinogenic in mice after chronic dermal application (De Pass et al. 1984). However, recently other authors reported a weak carcinogenic potential of AA and BA after chronic dermal administration to mice (Cote et al. 1986). The conditions of the latter study lead to the suggestion that the observed tumours had developed secondarily due to the local irritating and corrosive properties of AA and BA.This view is supported by the negative results of AA, EA and BA in the conventional Ames test (Waegemaekers and Bensink 1984). Mutagenicity data in mammalian cell systems of EA were equivocal (Henschler 1986) and were lacking for AA and BA. For this reason the mutagenic potential of AA and BA was investigated in Syrian hamster embryo fibroblasts (SHE cells). DNA repair (UDS assay), chromosomal changes (micronucleus assay) and morphological transformation were chosen as biological endpoints.     

Toxicity and oxidative stress induced by T-2 toxin in cultured mouse Leydig cells

To explore the toxic mechanism of T-2 toxin on Leydig cells of mice, we would investigate the toxicity and oxidative stress induced by T-2 toxin in the cells. Leydig cells were isolated and cultured with control or T-2 toxin (10^?7 M, 10^?8 M, or 10^?9 M) for 24?h, then cells and supernatants were harvested to examine cell viability, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities, expression of messenger RNA (mRNA) related to oxidative stress, malondialdehyde (MDA) content and DNA damage. The cell viability was evaluated in mouse Leydig cells by MTT assay, MDA content and SOD, GSH-Px and CAT activities were measured by routine kits, expression of mRNA related to oxidative stress were examined by quantitative real-time polymerase chain reaction (PCR), and DNA damage was investigated by comet assay. Leydig cells treated with T-2 toxin showed significant reductions in cell viability, SOD, GSH-Px and CAT activities, and expression of mRNA related to oxidative stress, and remarkable increases in MDA content and levels of DNA damage. This study proves that T-2 toxin is toxic to Leydig cells of mice. Furthermore, oxidative stress plays an important role in the above-mentioned negative effects of T-2 toxin.