Genotoxic effects of a particular mixture of acetamiprid and α‐cypermethrin on chromosome aberration,sister chromatid exchange,and micronucleus formation in human peripheral blood lymphocytes

The genotoxic effects of a particular mixture of acetamiprid (Acm, neonicotinoid insecticide) and α‐cypermethrin (α‐cyp, pyrethroid insecticide) on human peripheral lymphocytes were examined in vitro by chromosomal aberrations (CAs), sister chromatid exchange (SCE), and micronucleus (MN) tests. The human peripheral lymphocytes were treated with 12.5 + 2.5, 15 + 5, 17.5 + 7.5, and 20 + 10 μg/mL of Acm+α‐cyp, respectively, for 24 and 48 h. The mixture of Acm+α‐cyp induced the CAs and SCEs at all concentrations and treatment times when compared with both the control and solvent control and these increases were concentration‐dependent in both treatment times. MN formation was significantly induced at 12.5 + 2.5, 15 + 5, 17.5 + 7.5, μg/mL of Acm+α‐cyp when compared with both controls although these increases were not concentration‐dependent. Binuclear cells could not be detected sufficiently in the highest concentration of the mixture (20 + 10 μg/mL) for both the 24‐ and 48‐h treatment times. Mitotic index (MI), proliferation index (PI) and nuclear division index (NDI) significantly decreased because of the cytotoxic and cytostatic effects of the mixture, at all concentrations for two treatment periods. Significant decreases in MI and PI were concentration dependent at both treatment times. The decrease in NDI was also concentration‐dependent at 48‐h treatment period. In general, Acm+α‐cyp inhibited nuclear division more than positive control, mitomycin C (MMC) and showed a higher cytostatic effect than MMC. Furthermore, in this article, the results of combined effects of Acm+α‐cyp were compared with the results of single effects of Acm or α‐cyp (Kocaman and Topaktas, 2007 , 2009 , respectively). In conclusion, the particular mixture of Acm+α‐cyp synergistically induced the genotoxicity/cytotoxicity in human peripheral blood lymphocytes. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010.     

In vitro investigation of the genotoxic and cytotoxic effects of thiacloprid in cultured human peripheral blood lymphocytes

Thiacloprid, a neonicotinoid insecticide, is widely used for controlling various species of pests on many crops. The potential genotoxic effects of thiacloprid on human peripheral blood lymphocytes (PBLs) were investigated in vitro by the chromosome aberrations (CAs), sister chromatid exchanges (SCEs), and cytokinesis‐block micronucleus (MN) assays. The human PBLs were treated with 75, 150, and 300 μg/mL thiacloprid in the absence and presence of an exogenous metabolic activator (S9 mix). Thiacloprid increased the CAs and SCEs significantly at all concentrations (75, 150, and 300 μg/mL) both in the absence and presence of the S9 mix and induced a significant increase in MN and nucleoplasmic bridge formations at all concentrations for 24 h and at 75 and 150 μg/mL for 48‐h treatment periods in the absence of the S9 mix; and at all concentrations in the presence of the S9 mix when compared with the control and solvent control. Thiacloprid was also found to significantly induce nuclear bud (NBUD) formation at 300 μg/mL for 24 h and at 150 μg/mL for 48‐h treatment times in the absence of the S9 mix and at the two highest concentrations (150 and 300 μg/mL) in the presence of the S9 mix. Thiacloprid significantly decreased the mitotic index, proliferation index, and nuclear division index for all concentrations both in the absence and presence of the S9 mix. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 631–641, 2014.     

The Effects of Food Protector Biphenyl on Sister Chromatid Exchange,Chromosome Aberrations,and Micronucleus in Human Lymphocytes

The aim of this study was to determine the possible genotoxic effects of biphenyl (E230), which is used as an antimicrobial agent in food by using sister chromatid exchanges (SCEs), chromosome aberrations (CAs), and micronucleus (MN) tests in human peripheral lymphocytes. The human peripheral lymphocytes were treated with four concentrations of biphenyl (10, 30, 50, and 70 μg/mL) for 24- and 48-h treatment periods. In the present study, biphenyl significantly increased the frequency of SCEs, CAs, and the frequency of MN when compared with both untreated control and solvent (dimethyl sulfoxide) control. The inductions of these abnormalities were in a dose-dependent manner. Biphenyl was capable to induce the structural CAs instead of numerical CAs. Biphenyl also showed a cytotoxic effect by decreasing the replication index at the highest two concentrations for 48 h and nuclear division index at the highest two concentrations for the 24- and 48-h treatment periods. However, biphenyl did not affect the mitotic index (MI).     

Genotoxic effects of 4-methylimidazole on human peripheral lymphocytes in vitro

4-Methylimidazole (4-MEI), a heterocyclic organic chemical compound, is widely found in many foods and consumed by people worldwide. In this research, we aimed to investigate the cytotoxic and genotoxic effects of 4-MEI on human lymphocytes. For this purpose, human peripheral blood lymphocytes were treated with four concentrations of 4-MEI (300, 450, 600 and 750?μg/ml) for 24?h and 48?h periods and in vitro sister chromatid exchange (SCE), chromosome aberration (CA) and micronucleus (MN) tests were used. 4-MEI induced SCE in human peripheral lymphocytes at three highest concentrations (450, 600 and 750?μg/ml) in 48?h treatment period. CA and MN were induced in human peripheral lymphocytes at two highest concentrations of 4-MEI (600 and 750?μg/ml) in 24?h and 48?h treatment periods. The highest concentration of 4-MEI (750?μg/ml) induced MN formation more than the positive control MMC in 24?h treatment period. In addition, 4-MEI led to a decrease in MI at the highest concentration (750?μg/ml) in 24?h treatment period and at all concentrations in 48?h treatment period. 4-MEI reduced PI at all concentrations in 24?h treatment period and at all concentrations (expect the lowest) for 48?h treatment period. 4-MEI reduced nuclear division index (NDI) at 24 and 48?h treatment periods, even at the highest two concentrations, decreased more than the positive control MMC. Our results showed that 4-MEI pose a genotoxic and cytotoxic effects for human peripheral lymphocytes.     

The Cytogenetic Effects of Food Sweetener Maltitol in Human Peripheral Lymphocytes

The effects of the low-calorie artifical sweetener maltitol (E965), a sugar alcohol (Polyol), on sister chromatid exchange (SCE), chromosome aberration (CA), and micronucleus formation (MN) were investigated in human peripheral lymphocytes. Maltitol did not induce SCE at all concentrations (1.25, 2.5, and 5 mg/mL) and treatment periods (24 and 48 h). Maltitol induced CA, although not statistically significantly. Maltitol induced the frequency of MN at 24 and 48 h in a non-dose-dependent manner. In addition, maltitol did not decrease the replication index (RI) and the mitotic index (MI) at all concentrations and treatment periods. Maltitol did not alter the pH and osmolality of the medium. In conclusion, it can be concluded that maltitol has a weak genotoxic potential and it appears non-cytotoxic to human peripheral lymphocytes in vitro.     

The cytogenetic effects of food sweetener maltitol in human peripheral lymphocytes

The effects of the low-calorie artifical sweetener maltitol (E965), a sugar alcohol (Polyol), on sister chromatid exchange (SCE), chromosome aberration (CA), and micronucleus formation (MN) were investigated in human peripheral lymphocytes. Maltitol did not induce SCE at all concentrations (1.25, 2.5, and 5 mg/mL) and treatment periods (24 and 48 h). Maltitol induced CA, although not statistically significantly. Maltitol induced the frequency of MN at 24 and 48 h in a non-dose-dependent manner. In addition, maltitol did not decrease the replication index (RI) and the mitotic index (MI) at all concentrations and treatment periods. Maltitol did not alter the pH and osmolality of the medium. In conclusion, it can be concluded that maltitol has a weak genotoxic potential and it appears non-cytotoxic to human peripheral lymphocytes in vitro.     

The effects of food protector biphenyl on sister chromatid exchange, chromosome aberrations, and micronucleus in human lymphocytes

The aim of this study was to determine the possible genotoxic effects of biphenyl (E230), which is used as an antimicrobial agent in food by using sister chromatid exchanges (SCEs), chromosome aberrations (CAs), and micronucleus (MN) tests in human peripheral lymphocytes. The human peripheral lymphocytes were treated with four concentrations of biphenyl (10, 30, 50, and 70 microg/mL) for 24- and 48-h treatment periods. In the present study, biphenyl significantly increased the frequency of SCEs, CAs, and the frequency of MN when compared with both untreated control and solvent (dimethyl sulfoxide) control. The inductions of these abnormalities were in a dose-dependent manner. Biphenyl was capable to induce the structural CAs instead of numerical CAs. Biphenyl also showed a cytotoxic effect by decreasing the replication index at the highest two concentrations for 48 h and nuclear division index at the highest two concentrations for the 24- and 48-h treatment periods. However, biphenyl did not affect the mitotic index (MI).     

Investigation of genotoxic effects of paraben in cultured human lymphocytes

Paraben is a phenolic derivative of benzoic acid extensively used as preservatives in food, pharmaceutical, and cosmetic industries due to its antimicrobial characteristics. The objective of this study was to evaluate the in vitro genotoxic effects of paraben in human lymphocyte cultures. Cells were analyzed by cytokinesis-block micronucleus (CBMN), chromosome aberration (CA), sister chromatid exchange (SCE), and comet tests. For CBMN, CA, and SCE assays, the human lymphocytes were isolated from healthy donors and incubated with 500, 250, 100, and 50?µg/mL of paraben for 24 and 48?h, and for comet assay, cells were exposed to 1000, 750, 500, and 250?µg/mL of paraben for an hour. Results showed that numbers of MN and SCEs were not significant in the cells exposed to paraben when compared to the solvent control. However, 500 and 250?µg/mL of paraben induced the CA after 24?h. Also, we observed a significant decrease in the cytokinesis-block proliferation index in cells exposed 250–500?µg/mL paraben for 24?h, and 100, 250, and 500?µg/mL for 48?h. The mitotic index was also decreased at all concentrations and periods. However, the proliferation index was statistically decreased at all concentrations after 48?h treatments. Only the highest concentration of paraben caused DNA migration (mean tail length) in human lymphocytes analyzed by Comet assay. Taken together, results indicated that paraben had cytotoxic effects and caused genotoxicity by affecting directly chromosomes and DNA in human lymphocyte cells in vitro, and may have genotoxic potential for human.     

In vitro genotoxic and cytotoxic effects of some paraben esters on human peripheral lymphocytes

Parabens (PBs) are p-hydroxybenzoic acid ester compounds commonly employed as antimicrobial preservatives, mainly in food, cosmetic, and pharmaceutical products. The aim of the present study was to investigate the genotoxic and cytotoxic effects of some paraben esters (butyl paraben, propyl paraben, isobutyl paraben, and isopropyl paraben) on human peripheral lymphocytes, using in vitro sister chromatid exchange (SCE), chromosome aberration (CA), and cytokinesis-block micronucleus (CBMN) tests. Lymphocyte cultures were treated with four concentrations of PBs (100, 50, 25 and 10?µg/mL) for 24 and 48?h. Paraben esters significantly induced MN formations as compared to solvent control. Furthermore, butyl paraben and propyl paraben increased MN formations a concentration-dependent manner at 24 and 48?h. PBs increased the CA at 24 and 48?h. However, this increase was not meaningful for butyl paraben and isopropyl paraben at 48?h when compared with solvent control. Butyl, isobutyl, and isopropyl paraben significantly increased the SCE at 24 and 48?h. However, propyl paraben did not induce SCE meaningfully in both treatment periods. A significant decrease in the cytokinesis-block proliferation index and mitotic index was observed in cells exposed to all concentrations of PBs at 24 and 48?h. However, proliferation index was not affected at all concentrations of PBs after 24?h treatment, although it was decreased at the highest concentration of PBs at 48?h. It is concluded that all of the paraben esters used in this study have highly genotoxic and cytotoxic effects on human lymphocytes cells in vitro.     

In vitro potential cytogenetic and oxidative stress effects of roxithromycin

Macrolide antibiotic roxithromycin was evaluated in terms of its genotoxic, cytotoxic and oxidative stress effects. For this purpose; 25, 50, 100 and 200?μg/mL concentrations of roxithromycin were dissolved in dimethyl sulfoxide and treated to human peripheral blood lymphocytes for two different treatment periods (24 and 48?h). In chromosome aberration (CA) and micronucleus (MN) tests, roxithromycin did not show genotoxic effect. But it induced sister chromatid exchange (SCE) at the highest concentration (200?μg/mL) for the 24-h treatment period and at all concentrations (except 25?μg/mL) for the 48-h treatment period. Looking at cytotoxic effect of roxithromycin, statistically insignificant decreases on mitotic index and proliferation index were observed. Roxithromycin decreased nuclear division index (NDI) at highest two concentrations (100 and 200?μg/mL) for the 24-h treatment period and at all concentrations (expect 25?μg/mL) for the 48-h treatment period. Total oxidant values, total antioxidant values and oxidative stress index did not change with roxithromycin treatment. Eventually, roxithromycin did not have genotoxic and oxidative stress effects in human-cultured lymphocytes.     

Detection of genotoxicity and mutagenicity of chlorthiophos using micronucleus,chromosome aberration,sister chromatid exchange,and Ames tests

Potential mutagenic and genotoxic effects of Chlorthiophos, an organophosphate pesticide, were evaluated using four standard assays. Five different concentrations of the pesticide were tested by an Ames test using Salmonella typhimurium strains TA97, TA98, TA100, and TA102, with and without S9 metabolic activation. No concentrations of Chlorthiophos showed mutagenic activity on the TA97, TA100, and TA102 strains, with and without S9 fraction, but were all mutagenic to the TA98 strain without S9. Sister chromatid exchange (SCE), chromosome aberration (CA), and micronucleus (MN) tests were used to investigate the genotoxic effects of Chlorthiophos in human peripheral lymphocytes treated with 25, 50, 100, and 200 µg/mL concentrations of Chlorthiophos for 24 and 48 h. The nuclear division index (NDI), replication index (RI), and mitotic index (MI) were also calculated to determine the cytotoxicity of Chlorthiophos. No increase in SCE frequency was seen for any treatment period or concentration, but Chlorthiophos at 200 µg/mL increased the frequency of CAs. Increases in MN formation were only observed at Chlorthiophos concentrations of 200 µg/mL following 24 and 48 h treatments. Chlorthiophos treatment reduced the MI and NDI significantly, but had no effect on the RI. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 937–945, 2015.     

Micronuclei,nucleoplasmic bridges,and nuclear buds induced in human lymphocytes by the fungicide signum and its active ingredients (boscalid and pyraclostrobin)

The aim of this study was to investigate the genotoxic and cytotoxic potential of the Signum fungicide and its active ingredients (boscalid and pyraclostrobin) on human peripheral blood lymphocytes using the cytokinesis‐block micronucleus (CBMN) assay. Micronuclei (MNi), nucleoplasmic bridges (NPBs), nuclear bud (NBUDs) formations, and the cytokinesis‐block proliferation index (CBPI) were evaluated in treated lymphocytes in Go (cells were treated and then kept in culture without stimulation for 24 h) and proliferation phases (cells were treated after 44 h culture in medium containing phytohemagglutinin). MN formation in lymphocytes treated in G₀ statistically increased at doses of 2, 6, and 25 μg/mL signum; 0.5 and 2 μg/mL boscalid; and 0.5, 1.5, and 2 μg/mL pyraclostrobin; while NPB formation increased at a dose of 0.25 μg/mL pyraclostrobin. All concentrations of each fungicide did not statistically increase NBUD formation, while the cytotoxicity increased the dependent on concentration in lymphocytes treated in G₀. Doses of 0.5, 1, 1.5, and 3 μg/mL signum; 0.5, 1, and 1.5 μg/mL boscalid; and 0.75 μg/mL pyraclostrobin statistically increased the MN formation in proliferating lymphocytes. NPB formation increased in proliferating lymphocytes at doses of 1, 1.5, 2, and 3 μg/mL signum and at a dose of 0.75 μg/mL pyraclostrobin. In addition, a dose of 0.75 μg/mL pyraclostrobin increased NBUD frequencies. Cytotoxicity increased with increasing concentrations of each fungicide. It is concluded that signum, boscalid, and pyraclostrobin may be genotoxic and cytotoxic in vitro human peripheral blood lymphocytes in consideration of each of the two protocols. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 723–732, 2014.     

The genotoxic and antigenotoxic effects of Salvia fruticosa leaf extract in human blood lymphocytes

Abstract

The aim of this study was to investigate the genotoxic and antigenotoxic effects of Salvia fruticosa (Sf) leaf extract with the absence and presence of S9 mix using sister chromatid exchange (SCE), chromosome aberration (CA) and micronucleus (MN) formation test systems in human peripheral blood lymphocytes (HPBLs) that were treated with 1.5-, 3.0- and 6.0-µL/mL concentrations for 24- and 48-hour treatment periods. The cytotoxicity of Sf leaf extract was also investigated by calculating the mitotic index (MI), proliferation index (PI) and nuclear division index (NDI). In the absence of S9 mix, Sf leaf extract alone increased SCE frequency at the 48-hour treatment period; however, it induced the CA and MN at all concentrations and at all treatment periods. Sf plus MMC (mitomycin C) synergically induced SCE and CA, except the highest concentration of Sf leaf extract and MMC on induction of SCE. In addition, Sf leaf extract induced the effect of MMC on MN frequency for 24 hours, but it significantly decreased the effect of MMC on MN frequency for the 48-hour treatment period. Sf leaf extract showed a cytotoxic effect by decreasing the MI; however, it did not decrease the PI and NDI. In the presence of S9 mix, Sf leaf extract did not increase the SCE, when compared to solvent control, whereas it reduced the effect of cyclophosphamide (Cyp). Sf leaf extract induced the CA and MN, but could not increase the effect of Cyp on CA and MN formation. Sf leaf extract had no cytotoxic effect; however, it induced the cytotoxicity of Cyp.     

The in vitro genotoxic and cytotoxic effects of remeron on human peripheral blood lymphocytes

Remeron (Mirtazapine) is an antidepressant drug which exerts its action by blocking presynaptic α-2-adrenergic receptors and postsynaptic serotonin types 2 and 3 receptors. In this in vitro analysis, human peripheral blood lymphocytes was treated by remeron (10, 25, 40 and 55 μg/mL) for 24 hours and 48 hours periods, then it was attempted to study of genotoxic and cytotoxic effects of the substance on human peripheral blood lymphocytes by some tests such as sister chromatid exchange (SCE), chromosomal abnormalities (CA) and micronucleus (MN) tests. Also proliferating effect of the substance was investigated. Remeron didn’t significantly cause chromosomal abnormalities and sister chromatid exchange while caused micronucleus at 40 μg/mL concentration and 24?h periodic time and increased proliferation index of the both 24 and 48 hours treated cells was decreased in a concentration manner. Also, exposing to the remeron for 24 and 48 hours leaded to a decrease in mitotic index and nucleus division index in the cells by concentration dependent manner. These findings showed that remeron did not have significantly genotoxic effects on human peripheral blood lymphocytes while it showed cytotoxic effects on the cells, which is the first report on genotoxic and cytotoxic properties of remeron.     

Evaluation of genotoxic effects of 3-methyl-5-(4-carboxycyclohexylmethyl)-tetrahydro-2H-1,3,5-thiadiazine-2-thione on human peripheral lymphocytes

Context: Tranexamic acid is commonly used for curing abnormal bleeding in a variety of diseases. In a previous study, 12 different tetrahydro-2H-1,3,5-thiadiazine derivatives were synthesized from the amine group of tranexamic acid. Their antifibrinolytic and antimicrobial activities were compared with tranexamic acid. 3-Methyl-5-(4-carboxycyclohexylmethyl)-tetrahydro-2H-1,3,5-thiadiazine-2-thione (3-MTTT) was the most remarkable one, which may be used as a drug.

Objectives: In vitro genotoxicity of 3-MTTT was investigated using chromosome aberrations (CAs), sister chromatid exchanges (SCEs), micronucleus (MN) and comet assays.

Materials and methods: Various concentrations 0.78, 1.56, 3.13, 6.25, 12.50 and 25.00?μg/mL of 3-MTTT were applied to lymphocytes obtained from two donors for periods of 24 and 48?h. A negative (distilled water), a solvent (2:1 PBS:10% NaOH for cultured lymphocyte, and PBS for isolated lymphocytes) and a positive control (MMC for cultured lymphocytes and H₂O₂ for isolated lymphocytes) were also maintained.

Results: While this compound did not increase the frequency of abnormal cells and CA/cell ratio compared to negative control (except 48?h, 25?μg/mL), it significantly increased the frequency of SCEs at the four highest concentrations at both treatment periods (except 6.25?μg/mL, 48?h). It significantly decreased the MI in all the concentrations at 24?h (except 0.78?μg/mL) and in the highest three concentrations at 48?h. This compound did not significantly increase the frequency of MN and DNA damage compared to negative control. This compound did not affect the replication and nuclear division index.

Discussion and conclusion: Our results demonstrated that this compound does not represent a significant risk at the genetic level in in vitro human lymphocytes.     

Chromosomal aberrations in cultured human lymphocytes treated with the fungicide, Thiram

In vitro effects of different concentrations of Thiram were tested on human lymphocytes to determine, by means of the chromosome aberrations (CAs) assay, whether this fungicide could induce clastogenic damage. Evidences of the effect of Thiram on human lymphocytes were limited to sister chromatid exchange, micronuclei formation, and comet assays. We evaluated 0.01, 0.1, 1.2, and 12.0 μg/mL of Thiram, where 0.01 μg/mL represent the acceptable daily intake dose set by the World Health Organization and the Food and Agriculture Organization for fruit and vegetables, whereas 0.1, 1.2, and 12.0 μg/mL are its multiple values. Results indicated that human lymphocytes treated in vitro with Thiram at concentrations of 1.20 and 12.0 μg/mL significantly increased CAs frequency, compared with the negative control, whereas at lower concentrations (0.01 and 0.1 μg/mL), this effect was not observed. However, Thiram showed a clastogenic effect also at the concentration value of 1.2 μg/mL that represents a lower value with respect to the residue limits found in Italy for grapes, strawberries, potatoes, tobacco, and other fruits and vegetables. Finally, according to some evidence obtained from the study of other fungicides, Thiram produced a significant reduction in the mitotic index with increasing concentration.     

Chromosomal aberrations in cultured human lymphocytes treated with the fungicide,Thiram

In vitro effects of different concentrations of Thiram were tested on human lymphocytes to determine, by means of the chromosome aberrations (CAs) assay, whether this fungicide could induce clastogenic damage. Evidences of the effect of Thiram on human lymphocytes were limited to sister chromatid exchange, micronuclei formation, and comet assays. We evaluated 0.01, 0.1, 1.2, and 12.0 μg/mL of Thiram, where 0.01 μg/mL represent the acceptable daily intake dose set by the World Health Organization and the Food and Agriculture Organization for fruit and vegetables, whereas 0.1, 1.2, and 12.0 μg/mL are its multiple values. Results indicated that human lymphocytes treated in vitro with Thiram at concentrations of 1.20 and 12.0 μg/mL significantly increased CAs frequency, compared with the negative control, whereas at lower concentrations (0.01 and 0.1 μg/mL), this effect was not observed. However, Thiram showed a clastogenic effect also at the concentration value of 1.2 μg/mL that represents a lower value with respect to the residue limits found in Italy for grapes, strawberries, potatoes, tobacco, and other fruits and vegetables. Finally, according to some evidence obtained from the study of other fungicides, Thiram produced a significant reduction in the mitotic index with increasing concentration.     

Cytogenetic alterations in human lymphocyte cultures following exposure to ofloxacin

Ofloxacin (OFX), a second-generation of quinolones, is a broad-spectrum flouroquinolone antibiotic used in the treatment of various bacterial infections. In this article, we aimed to investigate the cytotoxic and genotoxic potentials of OFX in cultured human peripheral lymphocytes. The cytotoxicity and genotoxicity of OFX on human peripheral blood lymphocytes were examined in vitro by sister chromatid exchange (SCE), chromosomal aberrations (CAs) and micronucleus (MN) tests. Cultures were treated with 30, 60 and 120?μg/ml of OFX for 48?h. Dimethylsulfoxide (DMSO) was used as a solvent control. OFX decreased the mitotic index (MI) and nuclear division index (NDI) significantly, especially at higher concentrations (60 and 120?μg/ml) compared with solvent control. OFX signi?cantly induced CAs at all concentrations and SCEs at higher concentrations (60 and 120?μg/ml) compared with solvent control. In conclusion, our results indicated that OFX has cytotoxic, cytostatic and genotoxic potential especially at higher concentrations on human peripheral blood lymphocyte cultures under the experimental conditions.     

Genotoxic effects of chlorophenoxy herbicide diclofop-methyl in mice in vivo and in human lymphocytes in vitro

Diclofop-methyl (DM) is a chlorophenoxy derivative used in large quantities for the control of annual grasses in grain and vegetable crops. In this study, the genotoxic effects of DM were investigated by measuring chromosomal aberrations (CAs) in mouse bone-marrow cells and CA and the comet assay in human peripheral lymphocytes. Mice were treated with 15.63, 31.25, 62.5, and 125?mg/kg body weight of DM intraperitoneally for 24 hours, and 15.63-, 31.25-, 62.5-, 125-, and 250-μg/mL concentrations were applied to human lymphocytes for both 24 and 48 hours. In in vivo treatments, DM significantly, but not dose dependently, increased the total chromosome aberrations, compared to both negative and solvent controls. Cell proliferation was significantly, but not dose dependently, affected by all doses. In in vitro treatments, DM (except 15.63 μg/mL) significantly and dose dependently increased the frequency of chromosome aberrations. Also, 250 μg/mL of 48-hour treatment was found to be toxic. Cell proliferation was significantly and dose dependently affected by DM applications, when compared to negative control. In in vitro treatments, DM significantly decreased the mitotic index only at the highest concentration for 24 hours, and 62.5- and 125-μg/mL concentrations for 48 hours. In the comet assay, a significant and dose-dependent increase in comet-tail intensity was observed at 62.5-, 125-, and 250-μg/mL concentrations. The mean comet-tail length was significantly increased in all concentrations. Our results demonstrate that DM is genotoxic in mammalian cells in vivo and in vitro.     

Genotoxic and cytotoxic effects of doxycycline in cultured human peripheral blood lymphocytes

Doxycycline (DOX) is a broad-spectrum tetracycline antibiotic used in the treatment of many infections. In this study, the genotoxic and cytotoxic effects of DOX in cultured human peripheral blood lymphocytes were investigated by measuring chromosome aberrations (CAs), cytokinesis-block micronucleus (CBMN) assay, mitotic index (MI), and nuclear division index (NDI). Cultures were treated with DOX at three concentrations (2, 4, and 6 μg/mL) for 48 hours. Mitomycin C (MMC) was used as a positive control. All the tested concentrations of DOX for MI and the higher concentrations (4 and 6 μg/mL) for NDI significantly decreased mitotic activity. However, there are no significant differences between negative control and all the tested concentrations of DOX for CA and MN frequencies. In conclusion, our results indicate that DOX has a cytotoxic effect, but not a genotoxic effect, on human peripheral blood lymphocyte cultures. Further detailed studies, especially about the cell-cycle kinetics of DOX, are required to elucidate the decreases in dividing cells and make a possible risk assessment on cells of patients receiving therapy with this drug. Further, if the specific cytostatic and cytotoxic potential of DOX to different types of cancer cells is investigated in detail, it may also have been used as an antitumoral drug.