OBJECTIVETo study the effects of indium exposure on the relative content of mitochondrial ND1 gene in lymphocytes.

METHODSVenous blood was obtained from 14 healthy workers and anticoagulated with heparin. Blood lymphocytes were separated and divided into three tube cultures. For two tubes in the exposed group, indium chloride was added to final concentrations of 0.2 mmol/L and 0.8 mmol/L, respectively. For one tube in the control group, an equal volume of normal saline solution was added. After incubation for 72 h, the relative content of mitochondrial gene in each group was determined using quantitative real-time PCR.

RESULTSLymphocytes exposed to 0.8 mmol/L indium chloride had a significantly higher relative content of mitochondrial gene than those exposed to 0.2 mmol/L indium chloride and those in the control group (P < 0.05, P < 0.05).

CONCLUSIONLymphocytes exposed to a high concentration of indium and its compounds have an elevated relative content of mitochondrial ND1 gene, indicating increased oxidative DNA damage induced by exposure to a high concentration of indium and its compounds.

DNA Damage ; drug effects ; DNA, Mitochondrial ; genetics ; Humans ; Indium ; toxicity ; Lymphocytes ; drug effects ; NADH Dehydrogenase ; genetics ; Occupational Exposure

The defect or block of apoptosis is an important factor involved in the drug resistance of tumor cells. Blm gene plays a great role in DNA damage and repair. This study was aimed to explore the relationship of blm gene expression with cell cycle and apoptosis after Jurkat DNA damage. The apoptosis rate and change of cell cycle were detected by flow cytometry, the expression level of blm mRNA in Jurkat cells was determined by semi-quantitative RT-PCR. The results indicated that after induction with 0.4 g/L of mitomycin C (MMC) for 24 hours the apoptosis rate of Jurkat cells were (11.42±0.013)%, and (66.08±1.60)% Jurkat cells were arrested in G2/M phase. After induction for 48 hours, the apoptosis rate of Jurkat cells declined from (11.42±0.013)% to (8.08±0.27)%, and cell count of Jurkat cells arrested in G2/M phase decreased from (66.08±1.60)% to (33.96±1.05)%. When induced with 0.4 g/L of MMC for 24 hours, the apoptosis rate of fibroblasts and the percentage of fibroblasts in G2/M, G0-G1 and S phase all showed no significant change until 48 hours. The range of apoptosis rate and the change of cell percentage in three phases were significantly different between Jurkat cells and fibroblasts (p<0.01). Expression level of blm mRNA in Jurkat cells was remarkably higher than that in normal fibroblasts (p<0.01), at 48 hours expression level of blm mRNA was remarkably higher than that at 24 hours. The 2 groups showed clear difference of blm mRNA expression after treated by MMC (p<0.01). It is concluded that the blm gene may play a significant role in repair of DNA damage of Jurkat cells after MMC induction. Abnormal expression of blm is correlated to the drug resistance of leukemia cells.
Apoptosis ; Cell Cycle ; DNA Damage ; drug effects ; DNA Repair ; drug effects ; Humans ; Jurkat Cells ; Mitomycin ; pharmacology ; RecQ Helicases ; genetics

Single cell gel electrophoresis assay (SCGE), also named as alkaline comet assay, was a simple, rapid and sensitive method to evaluate DNA damage. In this study SCGE technique was used to monitor DNA damage difference in tumor patients caused by chemotherapy, DNA damage distribution frequency and DNA damage characters were analyzed by komet image analysis system (KIAS). The results showed that cyclophosphamide greatly caused DNA damage in lymphocytes of tumor patients. There was significant difference of peripheral blood lymphocyte DNA damage between tumor patients and healthy controls. Tail length of lymphocytes were 33.69 +/- 7.56 micro m, and tail DNA% we re 31.51 +/- 5.4 6% in 10 cancer patients treated with cyclophosphamide, while Tail length were 1 6.2 +/- 1.5 micro m and tail DNA% were 7.46 +/- 1.15% in healthy controls. there was great significant difference on tail length and tail DNA% values between cancer patients and healthy controls (P < 0.01). In conclusion, the successful measurement of DNA damage caused by Cyclophosphamide treatment means that the alkaline comet assay as a valuable tool can be very useful in cancer epideminology study, and also be valuable to evaluate DNA damage status of patients in clinic.
Comet Assay ; Cyclophosphamide ; adverse effects ; DNA Damage ; Electrophoresis, Agar Gel ; Humans ; Lymphocytes ; drug effects ; ultrastructure ; Neoplasms ; drug therapy ; genetics

OBJECTIVESThis study was conducted to explore effects of selenium on rat hepatocellular DNA damage induced by cadmium in vitro.

METHODSodium selenite was added at concentrations of 8.75, 17.50 and 35.00 micromol/L respectively with cadmium chloride at the concentrations of 8.75, 17.50 and 35.00 micromol/L respectively and rat hepatocellular DNA damage was measured with single cell gel electrophoresis (comet assay).

RESULTSSodium selenite at the concentration of 8.75 micromol/L inhibited DNA damage caused by cadmium chloride at the concentration of 8.75, 17.50 and 35.00 micromol/L in rat liver cells (P < 0.05). Although sodium selenite at 17.50 micromol/L inhibited DNA damage induced by cadmium chloride at 17.50 and 35.00 micromol/L, it did not inhibit DNA damage induced by cadmium chloride at 8.75 micromol/L. Sodium selenite at 35.00 micromol/L did not have antagonistic effects on DNA damage induced by cadmium chloride at 8.75, 17.50 and 35.00 micromol/L. In addition, sodium selenite at 8.75 micromol/L had the best antagonistic effect while cadmium chloride at 8.75 micromol/L, but the antagonistic effect of sodium selenite at 17.50 micromol/L was better than 8.75 micromol/L while cadmium chloride at 17.50 and 35.00 micromol/L.

CONCLUSIONThe antagonistic effect of selenium on rat hepatocellular DNA damage induced by cadmium related to the concentrations of selenium and also to the concentration ratio between selenium and cadmium.

Animals ; Cadmium ; toxicity ; Comet Assay ; DNA ; drug effects ; genetics ; DNA Damage ; drug effects ; Dose-Response Relationship, Drug ; Hepatocytes ; cytology ; drug effects ; metabolism ; Rats ; Selenium ; pharmacology

OBJECTIVETo observe calf thymus DNA damage induced by potassium dichromate in combination with glutathione (GSH).

METHODSAtomic force microscope and ultraviolet spectrum (UV) were used to observe the alterations of the DNA ultrastructure and absorption spectrum.

RESULTSAtomic force microscopy revealed no breaks of the DNA strand in response to treatment with potassium dichromate alone, but when coupled with GSH at proper concentrations, potassium dichromate induced alterations in the DNA structure and DNA fragmentation. UV examination also confirmed these findings by showing increased absorption intensity of the maximum UV peak following combined treatment of the DNA with potassium dichromate and GSH.

CONCLUSIONThese morphological and spectrographic evidences verified the important role of GSH in mediating the generation of various tumor-inducing intermediate products of potassium dichromate.

Animals ; Cattle ; DNA ; chemistry ; genetics ; DNA Damage ; DNA Fragmentation ; drug effects ; Glutathione ; toxicity ; Microscopy, Atomic Force ; methods ; Nucleic Acid Conformation ; drug effects ; Potassium Dichromate ; toxicity ; Spectrophotometry, Ultraviolet

The present study was aimed to investigate the damage effect of hepatocyte growrh promoting substance (HGS) on the HL-60 cell DNA in vitro and to explore the possible mechanism underlying the effect. Experiment was divided into 3 groups: one was control group, in which 0.9% NaCl solution was added, and other two were experimental group 1 and group 2, where 22.5 microg/ml and 40 microg/ml HGS were added, respectively. HL-60 cell growths were compared between groups with and without HGS. Single cell gel electrophoresis (SCGE) was used to detect DNA damage of HL-60 cell. DNA electrophoresis was used to detect the apoptosis of HL-60 cells caused by HGS. The results showed that the inhibitory effects of HGS on growth of HL-60 cells were observed in group with 22.5 microg/ml and group with 40 microg/ml after culture for 2 days, the DNA ladder and the apoptosis of HL-60 cells occurred in these 2 groups on day 2 after addition of HGS, the counts of HL-60 cells with comet tail in these experimental groups were found to be more increased in comparison with control group. In conclusion, the HGS can inhibit the growth of HL-60 cell and the apoptosis of HL-60 cells should be induced through pathway of DNA damage caused by HGS.
Animals ; Animals, Newborn ; Apoptosis ; drug effects ; genetics ; Cattle ; Cell Proliferation ; drug effects ; Comet Assay ; DNA Damage ; DNA, Neoplasm ; analysis ; genetics ; HL-60 Cells ; Humans ; Peptides ; pharmacology

OBJECTIVETo investigate the influence of cigarette smoking on human sperm DNA integrity.

METHODSTotally, 784 cases of male infertility were selected from our case database and grouped according to whether they were smokers or nonsmokers, how much they smoked (< or = 10, 11-19 and > or = 20 cigarettes/d) and how long they smoked (< or = 5, 6-9 and > or = 10 yr). Sperm DNA integrity was measured using sperm chromatin structure assay (SCSA) and flow cytometry. DNA fragmentation and immature spermatozoa were expressed by the DNA fragmentation index (DFI) and high DNA stainability (HDS) respectively. Conventional sperm parameters and sperm DNA integrity were compared among different groups.

RESULTSThe total semen volume and percentage of grade a + b sperm were lower and the sperm morphological abnormality was higher in the > or = 20 cigarettes/d and > or = 10 yr groups than in the others (P < 0.05). DFI and HDS were significantly higher in the smokers than in the nonsmokers (P < 0.05). HDS was negatively correlated with the percentage of grade a + b sperm (r = -0.18, P < 0.05) and both DFI and HDS were positively correlated with the rate of sperm malformation (r = 0.31 and r = 0.39, P < 0.05).

CONCLUSIONSmoking more than 20 cigarettes a day or longer than 10 years has deleterious effects on the semen volume, percentage of grade a + b sperm and sperm morphology of the smokers. Cigarette smoking decreases sperm DNA integrity and nuclear maturation.

Adult ; DNA Damage ; drug effects ; DNA Fragmentation ; Humans ; Infertility, Male ; genetics ; Male ; Middle Aged ; Smoking ; adverse effects ; Sperm Count ; Sperm Motility ; Spermatozoa ; drug effects ; Young Adult

OBJECTIVETo investigate the cyto-genotoxicity of 2, 2', 4, 4'-tetrabromodiphenyl ethers (PBDE-47) combined with 2, 2', 4, 4', 5-hexachlorobiphenyl (PCB153) treatment in SH-SY5Y cells.

METHODSExponentially growing SH-SY5Y cells were exposed to different concentrations of PBDE-47 or/and PCB153 for 24 h in vitro. Cell viability, DNA damage, chromosome abnormalities, and DNA-protein crosslinks (DPC) were measured using MTT, comet assay, cytokinesis-block micronucleus (CBMN) test, and SDS-KCl assay respectively.

RESULTSCompared to the each single PBDE-47 groups, the nuclear division index (NDI) was significantly lower (P < 0.05) and the frequencies of micronuclei (MNI), percentage of DNA in the tail, Olive tail moment and DPC were significantly increased (P < 0.05) in the PBDE-47 combined with PCB153 groups. There was a statistical decrease in cell viability in groups of 4 micromol/L PBDE-47 and above combined with PCB153 than that in contrast to the same dose of PBDE-47 group or PCB153 alone (P < 0.05). Significant increase was found in MNI frequency and DPC in 2 micromol/L PBDE-47 and above combined with PCB153 than those in the single PCB153 group (P < 0.05). In the groups of 4 micromol/L PBDE-47 and above combined with PCB153, the cell NDI were significantly lower than that of the single PCB153 group (P < 0.05). Compared to the single PCB153 group, the percentage of DNA in the tail and Olive tail moment was significantly increased in the 8 micromol/L PBDE-47 combined with 5 micromol/L PCB153. Factorial analysis showed that interactions between PBDE-47 and PCB153 existed in inhibiting cell viability, inducing DNA damage, MNI, and DPC formation (P < 0.01), and possessing synergistic effects.

CONCLUSIONSome dose of PBDE-47 combined with PCB153 can inhibit cell viability, induce DNA damage, DPC formation, and chromosome abnormalities. The pattern of the combined effect is synergistic in cyto-genotoxicity.

Cell Line, Tumor ; Cell Survival ; drug effects ; Comet Assay ; DNA Damage ; drug effects ; Drug Synergism ; Halogenated Diphenyl Ethers ; toxicity ; Humans ; Micronucleus Tests ; Neuroblastoma ; genetics ; pathology ; Polychlorinated Biphenyls ; toxicity

OBJECTIVETo investigate the main factors that influence the results of sperm alkaline single-cell gel electrophoresis (SCGE), optimize the conditions, and standardize its procedures.

METHODSUsing alkaline SCGE, we detected the DNA fragments of sperm treated with different concentrations of H2O2 and determined the influences of the number of agarose gel layers, pH during DNA unwinding and electrophoresis, the time of DNA unwinding and electrophoresis, and cumulative sperm number on the results of sperm alkaline SCGE. Then we optimized the procedures, analyzed the repeatability of the optimized method, and examined 40 semen samples using the method.

RESULTSThree agarose gel layers could reduce the background. The optimal pH during DNA unwinding and electrophoresis was 10, and the best times for DNA unwinding and electrophoresis were 40 min and 30 min, respectively. Fifty sperm were adequate to ensure the reliability of the results. Based on the percentage of tail DNA, the intra- and inter-assay repeatabilities of the optimized sperm alkaline SCGE were 3.12% and 7.13%, and by the DNA damage score, they were 2.38% and 6.09%, respectively. Sperm DNA fragments were significantly increased in the infertile patients with oligoasthenoteratozoospermia as compared with healthy fertile males (P <0.05).

CONCLUSIONThe optimized sperm alkaline SCGE, highly repeatable and easy to be standardized, can be applied to the clinical detection of sperm DNA fragmentation in infertile men.

Asthenozoospermia ; genetics ; Comet Assay ; standards ; DNA Damage ; DNA Fragmentation ; Humans ; Hydrogen Peroxide ; toxicity ; Male ; Oligospermia ; genetics ; Oxidants ; toxicity ; Reproducibility of Results ; Sperm Count ; Spermatozoa ; drug effects ; enzymology ; Time Factors

OBJECTIVEBenzo[a]pyrene (B[a]P), a ubiquitous environmental pollutant, is a potent procarcinogen and mutagen that can elicit tumors, leading to malignancy. Heat shock proteins (Hsp) have been shown to protect cells against damages caused by various stresses including exposure to numerous chemicals. Whether Hsps, or more specifically Hsp70, are involved in repair of B[a]P-induced DNA damage is currently unknown.

METHODSWe assessed the potential role of the inducible form of Hsp70 in B[a]P-induced DNA damage of human embryonic lung (HEL) cells using immunoblot and the comet assay (i.e., the single cell gel electrophoresis assay).

RESULTSExposure to B[a]P induced a dose-dependent decrease in the level of Hsp70, but a dose-dependent +-increase in DNA damage both in untreated (control) HEL cells and in cells preconditioned by a heat treatment. Heat preconditioning prior to B[a]P exposure potentiated the effect of B[a]P at a low dose (10 micromol/L), but appeared to be protective at higher doses. There was a negative correlation between Hsp70 level and DNA damage in the non-preheated as well as in the preconditioned cells.

CONCLUSIONThese data suggest that exposure of HEL cells to B[a]P may induce a dose-dependent reduction in the levels of the inducible Hsp70. The detailed mechanisms for the reduction of Hsp70 levels by B[a]P and the role of Hsp70 in DNA damage under different concentrations of B[a]P remains to be determined.

Benzo(a)pyrene ; Blotting, Western ; Carcinogens, Environmental ; Cells, Cultured ; Comet Assay ; DNA ; drug effects ; DNA Damage ; Dose-Response Relationship, Drug ; HSP70 Heat-Shock Proteins ; analysis ; biosynthesis ; genetics ; Humans