RESUMO
This work focuses on the possible use of phenanthro[9,10-c]-1,2,5-thiadiazole 1,1-dioxide (TDZ) as a harmless corrosion inhibitor. TDZ range-dose providing minimum adverse effects to the environment and human health, with satisfactory corrosion-inhibiting properties was evaluated. Cytotoxicity and genotoxicity of TDZ at 0.57-12.50 microM concentration range were tested by neutral red, chromosomal aberrations, mitotic index, and colony formation assays. Results showed a significant increase of chromatid-type aberrations for the highest concentration of TDZ assayed (12.50 microM). Additionally, a reduction in the proliferative rate for lower concentrations was detected by the MI assay. We concluded that TDZ should be used at concentrations lower than 1.16 microM. Corrosion assays performed showed good inhibition effect (ca. 50%) at low (0.65 microM) TDZ concentration. Consequently, our results indicated that TDZ induced a time- and dose-dependent genotoxic and cytotoxic response on CHO-K1 cells. Short assays should be complemented with long exposure tests to simulate chronic contact with TDZ since lower threshold levels may be found for shorter exposures and a wrong safety range could be determined.
Assuntos
Citotoxinas/toxicidade , Mutagênicos/toxicidade , Tiadiazóis/toxicidade , Animais , Células CHO , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Aberrações Cromossômicas/efeitos dos fármacos , Cromossomos/efeitos dos fármacos , Cromossomos/ultraestrutura , Corrosão , Cricetinae , Cricetulus , Dimetil Sulfóxido , Índice Mitótico , Vermelho Neutro , Ensaio Tumoral de Célula-TroncoRESUMO
The effects of ivermectin (IVM) and its commercial formulation ivomec (IVM 1.0%) were studied on Chinese hamster ovary (CHO(K1)) cells by several genotoxicity [sister chromatid exchange (SCE) and single cell gel electrophoresis (SCGE)] and cytotoxicity [cell-cycle progression (CCP), mitotic index (MI), proliferative replication index (PRI), 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and neutral red (NR)] bioassays within the 1.0-250 microg/ml concentration-range. While IVM and ivomec did not modified SCE frequencies, they induced DNA-strand breaks revealed by SCGE. An enhancement of slightly damaged cells and a decrease in undamaged cells were observed in IVM-treated cultures with 5.0-50.0 microg/ml. In ivomec((R))-treated cells, while an increase in slightly damaged cells was induced with 5.0-50.0 microg/ml, the damaged and undamaged cells increased and decreased only with 50.0 microg/ml. Both compounds exerted a delay in CCP and a reduction in PRI when 25.0 microg/ml was employed whereas cytotoxicity was observed at higher concentration than 50.0 microg/ml. No MI alteration was observed with 1.0-10.0 and 1.0-5.0 microg/ml of IVM and ivomec, respectively. A concentration-related trend to an increase in MI was achieved within 1.0-10.0 microg/ml. An increase in the MI was induced in 10.0 microg/ml ivomec-treated cultures. A marked reduction of about 89% and 62% in regard to controls was observed with 25.0 microg/ml of IVM and ivomec, respectively. NR and MTT assays revealed a cell growth inhibition when 0.25-250.0 microg/ml of both compounds was employed. The results highlighted that IVM and ivomec exert both genotoxicity and cytotoxicity in mammalian cells in vitro, at least in CHO(K1) cells.
Assuntos
Proliferação de Células/efeitos dos fármacos , Citotoxinas/farmacologia , Dano ao DNA/efeitos dos fármacos , Ivermectina/farmacologia , Mutagênicos/farmacologia , Animais , Antiparasitários/farmacologia , Antiparasitários/toxicidade , Células CHO , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Inseticidas/farmacologia , Inseticidas/toxicidade , Testes de Mutagenicidade , Mutagênicos/toxicidadeRESUMO
The aim of this study was to investigate the cytotoxic and genotoxic effect of copper extracts obtained from metallic copper in Chinese hamster ovary (CHO-K1) cell line using neutral red (NR), sister chromatid exchange (SCE), chromosomal aberrations (CA) and cell-cycle kinetics tests. Cells were cultured in Ham-F10 with different copper-containing extracts obtained after the immersion of copper disks for 1, 2, 3, 9, 12, 24, 48 and 72 h in culture medium. Results from cytotoxicity assay showed an inverted U-shape response evidenced in changes in lysosomal activity and mitotic index. The analysis of CA revealed an increase of abnormal metaphases for copper concentration (cCu) in the 5.67-7.42 mg/L dose-range (p<0.001). In addition, SCE frequencies were higher for treated cells when compared with controls in the 1.56-7.42 mg/L concentration range (p<0.001). The absence of metaphases indicated cytotoxicity for cCu≥10.85 mg/L. Results show that cells close to copper-containing materials releasing copper ions are susceptible to cytotoxic and genotoxic effects.
Assuntos
Células CHO/efeitos dos fármacos , Cobre/toxicidade , Íons/toxicidade , Animais , Aberrações Cromossômicas/efeitos dos fármacos , Cricetinae , Cricetulus , Meios de Cultura/farmacologia , Cinética , Mitose , Vermelho Neutro/farmacologia , Análise de Regressão , Troca de Cromátide Irmã , Espectrofotometria Atômica/métodos , Fatores de TempoRESUMO
Genotoxicity of the 2,4-dichlorophenoxyacetic acid (2,4-D) and a commercially-used derivative, 2,4-D dimethylamine salt (2,4-D DMA), was evaluated in CHO cells using SCE and single cell gel electrophoresis (SCGE) assays. Log-phase cells were treated with 2.0-10.0 microg/ml of herbicides and harvested 24 and 36 h later for SCE analysis. Both agents induced significant dose-dependent increases in SCE, regardless of the harvesting time (2,4-D: r=0.98 and r=0.88, P<0.01, for 24 and 36 h harvesting times; 2,4-D DMA: r=0.97 and r=0.88, P<0.01, for 24 and 36 h harvesting times). Neither test compound altered cell-cycle progression or proliferative replication index (P>0.05), but the higher doses of both compounds reduced the mitotic index of cultures harvested at 24 and 36 h (P<0.05). A 90-min treatment with 2.0-10.0 microg/ml 2,4-D and 2,4-D DMA produced dose-dependent increases in the frequency of DNA-strand breaks detected in the SCGE assay, both in cultures harvested immediately after treatment and in cultures harvested 36 h later. The doses of 2,4-D and 2,4-D DMA were equally genotoxic in all of the assays. The results indicate that 2,4-D induces SCE and DNA damage in mammalian cells, and should be considered as potentially hazardous to humans.
Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Dano ao DNA , Dimetilaminas/toxicidade , Herbicidas/toxicidade , Mutagênicos/toxicidade , Troca de Cromátide Irmã/efeitos dos fármacos , Animais , Células CHO , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Índice MitóticoRESUMO
The in vitro cytogenetic effects exerted by the dithiocarbamate fungicide zineb and one of its commercial formulations currently used in Argentina, azzurro, were studied in whole blood human lymphocyte cultures. The genotoxicity of the fungicides was measured by analysis of the frequency of chromosomal aberrations and sister chromatid exchanges (SCEs) and cell cycle progression assays. Both zineb and azzurro activities were tested within the range 0.1-100.0 microg/ml immediately after in vitro lymphocyte stimulation. Only concentrations of 50.0 and 100.0 microg/ml zineb and azzurro induced a significant increase in SCE frequency over control values. Furthermore, this genotoxicity appears to be correlated with its cytotoxicity, measured as cell cycle kinetics, since both a significant delay in cell cycle progression and a significant reduction in proliferative rate index were only observed in those cultures treated with these fungicide concentrations. For both chemicals, a progressive dose-related inhibition of the mitotic activity of cultures was observed when increasing the fungicide concentration. Moreover, only the mitotic activity statistically differed from control values when doses of zineb or azzurro <10 microg/ml were employed. For both fungicides the mitotic index reached the minimal value at doses of 100 microg/ml. Both products induced a significant dose-dependent increase in the number of abnormal cells, chromatid-type and chromosome-type aberrations as well as in the total number of aberrations in the 0.1-100.0 microg/ml dose range. Based on these results, the evaluation of zineb as a controversial genotoxic/non-genotoxic compound for human health should be reconsidered. Instead, we demonstrate that the fungicide induces large DNA alterations and should be considered as a clastogenic mutagen.
Assuntos
Fungicidas Industriais/toxicidade , Linfócitos/efeitos dos fármacos , Mutagênicos , Zineb/toxicidade , Adulto , Argentina , Biotransformação , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/genética , Células Cultivadas , Aberrações Cromossômicas/efeitos dos fármacos , Humanos , Masculino , Testes de Mutagenicidade , Troca de Cromátide Irmã/efeitos dos fármacos , Troca de Cromátide Irmã/genética , Zineb/análogos & derivadosRESUMO
The effect of pig monocytes (MNs) on the baseline frequency of sister chromatid exchanges (SCEs) and cell-cycle progression of pig lymphocytes was studied in plasma leukocyte (PLCs) and whole blood leukocyte cultures (WBCs). No variation in SCE frequency was observed between control WBC and PLC, nor did the addition of pig MNs to PLCs modify the baseline frequency of SCEs. Cell proliferation was slower in PLCs than in WBCs. Variations in cell-cycle progression of pig lymphocytes from PLC were observed both in the absence and presence of adherent cells in the culture. In MN-free cultures, lymphocytes proliferated foster than in parallel PLC cultures. However, when MNs were seeded into the cultures, cell-cycle progression gradually slowed as a function of the concentration of adherent cells present in the cultures. This finding shows that pig MNs modulate the in vitro cell-cycle progression of pig lymphocytes in a dose-dependent manner and that the low baseline SCE frequency of pig lymphocytes is independent of the presence or absence of MNs in the culture.
Assuntos
Ciclo Celular/fisiologia , Linfócitos/fisiologia , Monócitos/fisiologia , Troca de Cromátide Irmã/fisiologia , Animais , Adesão Celular , Divisão Celular , Células Cultivadas , Técnicas de Cocultura , Contagem de Leucócitos , Contagem de Linfócitos , Linfócitos/citologia , Masculino , SuínosRESUMO
The baseline sister-chromatid exchange (SCE) frequencies of human plasma lymphocyte cultures (PLC), but not pig PLC, were nearly twice as high as those of whole-blood cultures (WBC). Addition of human red blood cells (RBCs) to human PLC decreased the SCE frequency in proportion to the RBC-leukocyte co-incubation interval. When the period of RBC-leukocyte co-incubation was equivalent to the total length of the culture period (72 h), the SCE frequency was similar to that observed in WBC. Shorter co-incubation periods yielded SCE frequencies intermediate between those of PLC and WBC. Regardless of the species, cell proliferation was slower in PLC than in WBC. Experiments where RBCs were added to PLC showed that the time sequence of RBC incorporation also affects the cell-cycle progression of human and pig lymphocytes. When either human or pig RBCs were added immediately after PLC stimulation, the cell-cycle kinetics was similar to that of WBC. Shorter co-incubation periods made cell-cycle progression intermediate between PLC and WBC values. Thus, PBCs modulate the baseline frequency of SCEs in human PLC and the cell-cycle progression of both human and pig lymphocytes in a time-dependent manner. Two possible hypotheses for the heightened frequency of SCEs of human lymphocytes in RBC-free cultures were assessed. The loss of RBC-to-lymphocyte cellular contact in PLC did not influence the SCE frequencies of lymphocytes. Finally, the increase of SCEs in human PLC could not be related to differences in the generation time of lymphocytes in culture.