OBJECTIVETo explore the genotoxic effects of oral-exposed TiO2 nanoparticles on bone marrow cells in young rats.

METHODSTwenty-eight SD male young rats (4 weeks old) were randomly divided into 4 groups, which were exposed to TiO2 nanoparticles ((75 ± 15) nm, anatase) through intragastric administration at 0, 10, 50 and 200 mg/kg body weight (bw) every day for 30 days. The bone marrow cells were collected for micronuclei and γ-H2AX immunofluorescence analysis.

RESULTSThe percentage of γ-H2AX foci-positive cells (37.4 ± 10.0)% in the 50 mg/kg bw dose group were significantly higher than that in the control group (19.8 ± 3.1)% (t value was -17.59, P < 0.01). No significantly difference was found in polychromatic erythrocyte/normochromatic erythrocyte (PCE/NCE) ratio and PCE micronucleus rate between three experimental groups and control group.

CONCLUSIONTiO2 nanoparticles can increase the frequency of DNA double-strand breaks in bone marrow cells, but has no effect on micronucleus of bone marrow cells in young rats.

Animals ; Bone Marrow Cells ; DNA Damage ; Histones ; Male ; Micronuclei, Chromosome-Defective ; Nanoparticles ; Rats ; Titanium

Adult ; Chromosome Aberrations ; drug effects ; Ethylene Oxide ; poisoning ; Humans ; Lymphocytes ; drug effects ; pathology ; Male ; Micronuclei, Chromosome-Defective ; drug effects

OBJECTIVETo explore a flow cytometry (FCM)-based method for discriminating aneugen- or clastogen-induced micronuclei.

METHODSCells were stained with anti-CD71-FITC and PI, and the PI fluorescent signal intensity of micronucleated reticulocyte (MN-RET) in the peripheral blood of NIH mouse treated with COL or CP was detected by flow cytometry.

RESULTSThe ratio of the median of the intensity of MN-RET fluorescent signals to that of nucleated cell was low in the cyclophosphamide treated mouse, while the median was high in the colchicine treated mouse.

CONCLUSIONThe flow cytometry-based micronucleus assay can be used to discriminate primarily smaller MN induced by the clastogen exposure from the larger MN induced by an aneugen.

Animals ; Colchicine ; toxicity ; Cyclophosphamide ; toxicity ; Flow Cytometry ; methods ; Male ; Mice ; Micronuclei, Chromosome-Defective ; Mutagens ; toxicity ; Reticulocytes ; drug effects ; ultrastructure

OBJECTIVETo explore the genotoxicity of bass wood dust.

METHODSMicronucleus frequency in peripheral lymphocytes of workers exposed to bass wood dust in a match factory were examined, solution of bass wood dust emmersion was prepared and the effect on micronucleus frequency in poly-dyeing red blood cell of mice's sternum marrow was also detected. Single cell gel electrophoresis assay was used to detect DNA damage in liver cell, the level of oxygen free radical, lipid peroxidation(MDA) in the liver and the activity of superoxide dismutase(SOD) in red blood cells were also studied.

RESULTSThe positive frequency of micronucleus in bass wood-exposed workers with different length of service (0-, 5-, > or = 10 a) were 50.0%, 51.9%, 50.0% respectively, significantly higher (P < 0.01) than that of the control group(4.5%). A dose-effect relationship could also be found in the mice's micronucleus frequency study(r = 0.78, P < 0.01). The activities of SOD[(10.98 +/- 5.74), (15.70 +/- 7.54), (29.63 +/- 14.97) microgram/g Hb] were significantly lower than that of control group[(35.80 +/- 12.92) microgram/g Hb], and the level of MDA[(4.93 +/- 0.90), (4.61 +/- 1.06), (4.33 +/- 0.69) mmol/g liver] were significantly higher than that of the control group[(2.51 +/- 0.34) mmol/g liver]. Single cell gel electrophoresis study showed DNA strand breaks increased with the dose increase and the level of oxygen free radical also increased with the dose increase.

CONCLUSIONBass wood dust may have certain degree of genotoxicity.

Animals ; DNA Breaks ; Dust ; Humans ; Malondialdehyde ; analysis ; Mice ; Micronuclei, Chromosome-Defective ; Micronucleus Tests ; Occupational Exposure ; adverse effects ; Wood

OBJECTIVETo investigate cytotoxicity and genotoxicity of benzo(a)pyrene (B(a)P) by 16HBE-CYP1A1 cells which are human bronchial epithelial cell with CYP1A1 transformed.

METHODSExpression of CYP1A1 and mEH of cell models were tested by real-time quantitative polymerase chain reaction. Cells were treated with 0, 1, 5, 10 and 20 micromol/L B(a)P for 24 h. Adverse effects of B(a)P were tested by cytokinesis-block micronucleus (CBMN) cytome assays. Cytotoxicity was assessed by the nuclear division index (NDI), frequency of necrotic and apoptotic cells. Genetic damages were assessed by frequencies of CBMN, nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs).

RESULTSHigh levels of CYP1A1 and mEH were found in 16HBE-CYP1A1 cells (relative mRNA content was 7.8 x 10(-4) and 0.030 respectively). In 16HBE-CYP1A1 cells, NDI were decreased in 1, 5, 10 and 20 micromol/L B(a)P treated groups, 1.92 +/- 0.04, 1.71 +/- 0.01, 1.61 +/- 0.04, and 1.41 +/- 0.01, respectively; and lower than control group (2.08 +/- 0.03). Compared with control group ((82.67 +/- 6.66)%), the binucleated cells ratios were decreased, (76.33 +/- 3.51)%, (66.33 +/- 0.58)%, (51.67 +/- 1.53)% and (39.0 +/- 1.0)% respectively.Necrotic cells ratios were (1.93 +/- 0.42)%, (2.20 +/- 0.53)%, (8.07 +/- 0.90)% and (15.27 +/- 2.80)%, respectively, higher than control group ((0.47 +/- 0.11)%). The differences were significant (F values were 899.94, 303.33, 240.87, P < 0.01). Apoptotic cells were increased at lower groups and decreased to normal at higher groups treated by B(a)P. They were (1.20 +/- 0.53)%, (2.00 +/- 0.20)%, (1.47 +/- 0.12)%, (1.20 +/- 0.00)% and (1.20 +/- 0.00)%, respectively. Analysis on biomarkers of genetic damage, the significant dose-effect relationship were observed in NPBs and NBUDs (F values were 50.23, 121.09, P < 0.01, respectively). Frequencies of NPBs were (4.67 +/- 2.89) per thousand, (7.33 +/- 1.53) per thousand, (10.67 +/- 2.08) per thousand and (11.00 +/- 1.00) per thousand respectively. Frequencies of NBUDs were (2.33 +/- 0.58) per thousand, (4.00 +/- 1.00) per thousand, (5.00 +/- 1.00) per thousand, and (7.67 +/- 1.16) per thousand respectively. However, the dose-relationship of CBMN last only to 10 micromol/L B(a)P treated groups in 16HBE-CYP1A1 cells, and frequencies of CBMN were (8.33 +/- 3.21) per thousand, (14.67 +/- 1.15) per thousand, respectively. Frequency of CBMN was (16.67 +/- 2.88) per thousand in 20 micromol/L B(a)P treated group, lower than 10 micromol/L B(a)P treated group ((17.67 +/- 2.08) per thousand). In 16HBEV control cells, the cytotoxicity was found only in higher B(a)P treated groups and frequencies of CBMN, NPBs and NBUDs were increased also. While no significant differences were observed between 5, 10, 20 micromol/L B(a)P treated groups (they were (6.37 +/- 2.08) per thousand, (9.33 +/- 1.52) per thousand, (9.33 +/- 3.21) per thousand; (4.33 +/- 1.53) per thousand, (6.00 +/- 2.65) per thousand, (5.33 +/- 1.53) per thousand and (2.33 +/- 0.58) per thousand, (3.33 +/- 1.16) per thousand, (3.67 +/- 1.16) per thousand, respectively).

CONCLUSIONSThe genetic damages were more severe after treated with activated B(a)P, which may be induced by decreased NDI, increased necrotic cells and inhibition of apoptosis.

Apoptosis ; drug effects ; Benzo(a)pyrene ; toxicity ; Cell Division ; drug effects ; Cell Line, Transformed ; DNA Damage ; Humans ; Micronuclei, Chromosome-Defective

OBJECTIVETo study that low-intensity microwave whether or not enhances the genotoxic effects of mitomycin C(MMC) on human lymphocytes.

METHODSSingle strand DNA breaks and chromosomal aberrations were measured by comet assay and cytokinesis-blocked micronucleus(CBMN) test in vitro when human lymphocytes were exposed to 2,450-MHz microwave (5.0 mW/cm2) alone and in combination with mitomycin C.

RESULTSIn the comet assay, the average comet lengths of microwave group[(29.1 +/- 8.1) micron in male and (25.9 +/- 7.5) micron in female] were not significantly different from those of control groups [(26.3 +/- 6.6) and (24.1 +/- 4.3) micron respectively] (P > 0.05). The average comet lengths of MMC group(0.0125, 0.0250, 0.0500, 0.1000 microgram/ml) were significantly longer than those of control groups (P < 0.01) and were increased with the dose of MMC. The average comet lengths of microwave combined with MMC (MW + MMC) also were increased with the doses of MMC and were significantly longer than those of control groups (P < 0.01). When MMC was > or = 0.0250 microgram/ml, microwave and MMC synergistically increased the single strand DNA breaks. In the micronucleus test, the average micronucleus rates of microwave groups were not higher than those of control groups (P > 0.05). The average micronucleus rates of MMC groups and MW + MMC groups were significantly higher than those of control groups (P < 0.01) when MMC was > or = 0.0500 microgram/ml. The average micronucleus rates of MW + MMC groups seemed higher than those of corresponding MMC groups, however the difference was not significant (P > 0.05).

CONCLUSIONLow-intensity(2,450-MHz) microwave did not induce DNA and chromosome damages on human lymphocytes, but enhanced the effects of DNA breaks induced by MMC.

Chromosome Aberrations ; Comet Assay ; DNA Breaks, Single-Stranded ; Female ; Humans ; Lymphocytes ; drug effects ; radiation effects ; ultrastructure ; Male ; Micronuclei, Chromosome-Defective ; Microwaves ; adverse effects ; Mitomycin ; toxicity

OBJECTIVETo investigate the application of micronucleus test of buccal mucosal cells in monitoring the genetic effect of acrylonitrile in the population exposed to the acrylonitrile.

METHODSForty-one healthy male workers in a chemical factory in Shanghai were selected as the low concentration acrylonitrile exposed group while forty-seven healthy male workers in an acrylonitrile factory in Shanghai were selected as the intermediate concentration acrylonitrile exposed group. At the same time, thirty-one male workers who had no toxicant exposure and lived in the same community were selected as the control group. The micronucleus test in buccal mucosal cells and lymphocytes were used respectively for assessing the genetic damage status of these men.

RESULTSThe rate of micronucleus in buccal mucosal cells in both acrylonitrile groups (the low concentration group: 3.68% +/- 2.72%; the intermediate concentration group: 4.00% +/- 2.38%) was significantly higher than that in the control group (2.03% +/- 2.20%) (P < 0.05). The rate of micronucleus in the intermediate concentration group (4.23% +/- 3.34%) was significantly higher than that in the control group (2.48% +/- 1.46%) (P < 0.05). There was the correlation between the micronucleus test of buccal mucosal cells and the micronucleus test of the lymphocytes in the peripheral blood in the acrylonitrile exposed population (r = 0.299-0.359, P < 0.05).

CONCLUSIONThe micronucleus test of buccal mucosal cells replacing the micronucleus test of the lymphocytes in the peripheral blood can be used as one of the screening indexes in the surveillance of the genetic damage in the acrylonitrile exposed population.

Acrylonitrile ; toxicity ; Adult ; Carcinogens ; toxicity ; Dose-Response Relationship, Drug ; Humans ; Lymphocytes ; drug effects ; Male ; Micronuclei, Chromosome-Defective ; chemically induced ; Micronucleus Tests ; Mouth Mucosa ; cytology ; Occupational Exposure

OBJECTIVEUsing the stable HSPA1A (HSP70-1) promoter-driven luciferase reporter HepG2 cells (HepG2/HSPA1A cells) to assess the overall toxicity of coke oven emissions.

METHODSThe stable HepG2/HSPA1A cells were treated with different concentrations of coke oven emissions (COEs) collected from the top, side, and bottom of a coke oven battery for 24 h. After the treatments, luciferase activity, cell viability, malondialdehyde (MDA) concentration, Olive tail moment, and micronuclei frequency were determined, respectively.

RESULTSThe bottom COEs induced significant increases (P < 0.01) in relative luciferase activity up to 1.4 times the control level at 0.15 µg/L. The low dose of side COEs (0.02 µg/L) led to a significant increase (P < 0.01) in relative luciferase activity that progressively increased to 2.1 times the control level at 65.4 µg/L. The top COEs produced a strong dose-dependent induction of relative luciferase activity up to over 5 times the control level at the highest concentration tested (202 µg/L). In HepG2/HSPA1A cells treated with the bottom COEs, relative luciferase activity was positively correlated with MDA concentration (r = 0.404, P < 0.05). For the three COEs samples, positive correlations were observed between relative luciferase activity and Olive tail moment and micronuclei frequency.

CONCLUSIONThe relative luciferase activity in HepG2/HSPA1A cells can sensitively reflect the overall toxicity of COEs. The stable HepG2/HSPA1A cells can be used for rapid screening of the overall toxicity of complex air pollutants in the workplace.

Coke ; toxicity ; Genes, Reporter ; HSP70 Heat-Shock Proteins ; genetics ; Hep G2 Cells ; Humans ; Luciferases ; genetics ; Malondialdehyde ; analysis ; Micronuclei, Chromosome-Defective ; Occupational Exposure ; Promoter Regions, Genetic ; Toxicity Tests

OBJECTIVETo investigate the effect of CCM3 gene defection on lead induced cell genotoxicity in mouse embryonic fibroblasts.

METHODSC57 female mice were mated with CCM3 gene heterozygous male mice. E13.5 embryos were taken to isolate primary mouse embryonic fibroblasts. After genotyping, wild type and heterozygous cells were treated with different doses of lead acetate. Cell viability, genotoxicity and protein expression were detected by MTS assay, CB micronucleus method and Western blot, respectively.

RESULTSMouse embryonic fibroblasts with lead acetate treatment for 24 h, wild-type cells 100.00 µmol/L lead acetate-treated group (69.16±1.36) and the control group (100.00±2.33) compared to cells decreased by 30%, CCM3 heterozygous type cell 100.00 µmol/L lead acetate-treated group (87.16±5.50) and the control group (100.00±2.06) compared to cells decreased by 13%, the difference was statistically significant (F values were 98.59, 82.63, P<0.001). Lead acetate treatment after 48 h, wild-type cells 100.00 µmol/L lead acetate-treated group (51.99±5.62) and the control group (100.00±3.11) compared to cells decreased by 50%, heterozygous type cells 100.00 µmol/L lead acetate treatment group (66.33±4.06) and the control group (100.00±5.72) compared to cells decreased by 35%, the differences were statistically significant (F values were 82.63, 36.86, P < 0.001). The results of CBMN test showed that with increased dose, micronucleus cell rate of two genotypes showed an increasing trend, in the wild-type cells, the micronucleus cell rate (/1 000) for the control group, 29.6±2.2, 6.25 µmol/L dose group 47.3±6.6, 25 µmol/L dose group 55.5±9.1, 100.00 µmol/L dose group 66.8±3.5; heterozygous cells micronucleus cell rate (/1 000) for the control group, 35.3±5.6, 6.25 µmol/L dose of 50.0±8.3, 25.00 µmol/L dose group 57.0±8.5, 100.00 µmol/L dose group 58.8±2.1. Micronucleus cell rates (/1 000) were significant differences, in 100.00 µmol/L dose groups of two genotypes. Western blot results showed that wild-type cells CCM3 expression 100.00 µmol/L lead acetate-treated group (0.70±0.03) was 1.32 times higher than the control group (0.53±0.07), heterozygous cells CCM3 expression 100.00 µmol/L lead acetate-treated group (0.48±0.02) was 1.77 times higher than control group that of 0.27±0.04, there was statistically significant difference (F values were 14.77, 25.74, P < 0.001); wild-type cells γ-H2AX expression 100.00 µmol/L lead acetate-treated group (0.69±0.03) was 1.06 times higher than the control group (0.65±0.07), heterozygous cells γ-H2AX expression 100.00 µmol/L lead acetate-treated group (0.99±0.04) was 1.55 times higher than the control group CCM3 expression levels (0.64±0.06), there was statistically significant difference (wild-type cells: F = 7.08, P = 0.012, heterozygous type cell: F = 13.49, P = 0.002).

CONCLUSIONCCM3 gene may play a role in lead-induced genetic toxicity of mouse embryonic fibroblasts, CCM3 gene-lead interactions effects on mouse embryonic fibroblasts cell toxicity.

Animals ; Apoptosis Regulatory Proteins ; DNA Damage ; Embryo, Mammalian ; Female ; Fibroblasts ; Genotype ; Male ; Membrane Proteins ; Mice ; Mice, Inbred Strains ; Micronuclei, Chromosome-Defective ; Organometallic Compounds ; Proto-Oncogene Proteins

OBJECTIVETo investigate the relationship between the urinary 1-hydroxypyrene level and cytokinesis-block micronucleus and the olive moment of comet assay in peripheral blood lymphocyte in coke oven workers.

METHODSOne hundred and thirty-three workers from a coke plant and 28 referents without occupational PAH exposure were recruited in this study. Urinary level of 1-hydroxypyrene was measured by alkaline hydrolysis combined with high performance liquid chromatography as an internal exposure dose, and the DNA and chromosomal damage of peripheral blood lymphocyte were evaluated with comet assay and cytokinesis-block micronucleus method. Personal information including occupational history, age, sex, smoking and alcohol drinking, was collected by questionnaire.

RESULTSThere existed a good correlationship between the urinary level of 1-hydroxypyrene and frequency of micronuclei per 1 000 binucleated cells or the olive moment of comet assay in the study subjects, after adjusting for sex, age, smoking and alcohol drinking (r > 0.25, P < 0.01). One hundred and sixty-one subjects were divided into three groups by their urine 1-hydroxypyrene level (expressed as 0.30 - 2.44, 2.45 - 7.09 and 7.10 - 33.10 micro mol/mol Cr), and the geometric means of their urinary levels of 1-hydroxypyrene were 1.14, 4.32 and 12.49 micro mol/mol Cr, respectively. After adjusting for age, sex, smoking and alcohol drinking by multiple nonparametric analysis of covariance, the median of olive moment of comet assay in the group of 7.10 - 33.10 micro mol/mol Cr was 3.67, significantly higher than that in the groups of 0.30 - 2.44 and 2.45 - 7.09; and the micronuclei frequencies in the groups of 2.45 - 7.09 and 7.10 - 33.10 micro mol/mol Cr were 8.00 per thousand and 7.50 per thousand, respectively, significantly higher than that in the group of 0.30 - 2.44 micro mol/mol Cr (6.00 per thousand ).

CONCLUSIONSThe comet assay of peripheral blood lymphocyte was more suitable to detect the PAHs-induced early genotoxicity, than the cytokinesis-block micronucleus.

Adult ; Coke ; adverse effects ; Comet Assay ; Female ; Humans ; Male ; Micronuclei, Chromosome-Defective ; drug effects ; Micronucleus Tests ; Occupational Exposure ; adverse effects ; Pyrenes ; metabolism