Effect of selenium on cadmium-induced chromosomal aberrations in bone marrow cells of mice

Selenium, which is regarded as nature's antidote to heavy metal toxicities, was administered to mice. Salt solutions of cadmium chloride and sodium selenite were gavaged singly and successively, with or without a time gap of 1 h. Degrees of protection offered by this element against cadmium-induced toxic effects with special reference to chromosomal aberrations were assessed.     

Mutagenicity and chromosomal aberrations as an analytical tool for in vitro detection of mammalian enzyme-mediated formation of reactive metabolites

1. Incubation of trichloroethylene, 1,1-dichloroethylene, vinylchloride, tetra-chlorocyclopentadiene, the nitroso derivatives of the pesticides Carbaryl, Prometryn, and Dodin in the presence of metabolically active mouse liver microsomes and bacteria as target cells were mutagenic, whereas tetrachloroethylene, 1,2 cis- and transdichloroethylene, hexachlorocyclopentadiene, carbontetrachloride, chloroform, halothane, trichlorofluoromethane and styrene were not activated to mutagenic species. 2. In a similar in vitro test system using freshly isolated human lymphocytes as target cells dimethylnitrosamine induced chromosomal aberrations. 3. It is concluded from the experiments that submammalian or mammalian in vitro cell systems with metabolically active liver microsomes are not only suitable to screen for chemical mutagens but to demonstrate formation of reactive intermediates, which are short lived and cannot be detected by chemical procedure.     

No induction of structural chromosomal aberrations in cylindrospermopsin-treated CHO-K1 cells without and with metabolic activation

Cylindrospermopsin (CYN) is a cyanobacterial alkaloid that has been implicated in outbreaks of human morbidity and animal mortality. The principal mode of action for CYN is inhibition of protein and glutathione synthesis, and its toxicity seems to be mediated by cytochrome P-450-generated metabolites. It was also shown that CYN might be responsible for tumor initiation in animals; nevertheless, mechanisms leading to CYN-induced carcinogenesis are scarce and equivocal. The aim of the present study was to investigate the impact of metabolic activation on CYN-induced DNA damage. The effect of different doses of CYN (0.05–2 μg/ml) on DNA damage was determined in CHO-K1 cells after 3, 16 and 21 h of the treatment. The chromosome aberration assay with and without metabolic activation was applied to evaluate the clastogenic activity of CYN and its metabolite(s). In addition, the occurrence of apoptosis and necrosis was estimated by the annexin method using flow cytometry. The results revealed that CYN is not clastogenic in CHO-K1 cells irrespective of S9 fraction-induced metabolic activation. However, CYN significantly decreases the frequencies of mitotic indices and decreases proliferation irrespective of metabolic activation system. CYN increases the frequency of necrotic cells in a dose- and time-dependent manner, whereas it has a very slight impact on apoptosis. Moreover, the presence of metabolic activation influences a susceptibility to necrotic cell death but not an apoptotic one.     

Histidine increases the frequency of chromosomal aberrations induced by the xanthine oxidase-hypoxanthine system in V79 cells

The combined effects of the xanthine oxidase (XO)-hypoxanthine (HX) system and the various kinds of amino acids in Eagle's minimum essential medium on chromosomal aberrations were studied in Chinese hamster V79 cells. Among 13 amino acids tested, only histidine significantly increased the number of aberrant chromosomes and cytotoxicity in combination with the XO-HX system. This enhancing effect of histidine on chromosomal aberrations was dose-dependent at 0.063% - 0.25%; it was not affected by superoxide dismutase, but was strongly inhibited by catalase.     

The nature of chromosomal aberrations detected in humans exposed to benzene

Benzene is an established cause of human leukemia that is thought to act by producing chromosomal aberrations and altered in cell differentiation. In several recent studies increased levels of chromosomal aberrations in peripheral blood lymphocytes were correlated with a heightened risk of cancer, especially hematological malignancies. Thus, chromosomal aberrations may be a predictor of future leukemia risk. Previous studies exploring whether benzene exposure induces chromosomal aberrations have yielded mostly positive results. However, it remains unclear whether the chromosomal aberrations induced by benzene occur in a distinct pattern. Here, we thoroughly review the major chromosome studies published to date in benzene-exposed workers, benzene-poisoned and preleukemia patients, and leukemia cases associated with benzene expose. Although three cytogenetic markers (chromosomal aberrations, sister chromatid exchanges, and micronuclei) are commonly examined, our primary focus is on studies of chromosomal aberrations, because only this marker has so far been correlated with increased cancer risk. This review surveys the published literature, analyzes the study results, and discusses the characteristics of effects reported. In most studies of currently exposed workers, increases in chromosomal aberrations were observed. However, due to the relatively small number of affected individuals and variability in the reported aberrations, firm conclusions cannot be made about the involvement of specific chromosomes or chromosome regions. Further, in leukemia cases associated with benzene exposure, there is no evidence of a unique pattern of benzene-induced chromosomal aberrations in humans. Leukemia cases associated with benzene exposure are, however, more likely to contain clonal chromosome aberrations then those arising de novo in the general population.     

Frequency of chromosomal aberrations in peripheral lymphocytes of tannery workers in Brazil

To evaluate the incidence of chromosomal aberrations (CA) in peripheral lymphocytes of workers chronically exposed to chemical hazards in a tannery in Franca, São Paulo, Brazil. The exposed group consisted of 10 male workers employed in the same tannery. The duration of work in the tannery ranged from 5 months to 14 years. The control group consisted of 10 males without a history of exposure to chemicals or other potentially genotoxic substances. A total of 100 well-spread metaphases were analyzed per subject. The frequency of CA was higher in the exposed group than in the control group. Smoking had a significant effect on the frequency of CA in both the control and the exposed groups. Chronic occupational exposure of tannery workers represents a relevant risk factor for the development of diseases associated with genetic damage.     

Antimutagenic potential of Solanum lycocarpum against induction of chromosomal aberrations in V79 cells and micronuclei in mice by doxorubicin

Solanum lycocarpum A. St. Hil. (Solanaceae) is a hairy shrub or small much-branched tree of the Brazilian Cerrado. S. lycocarpum fruits are commonly used in traditional medicine in powder form or as folk preparations for the treatment of diabetes and obesity, as well as for controlling cholesterol levels. The aim of the present study was to chemically characterize the hydroalcoholic extract (SL) of S. lycocarpum by determination of total flavonoids and total poyphenols and quantification of steroidal alkaloids, as well as to evaluate its mutagenic and/or antimutagenic potential on V79 cells and Swiss mice using chromosomal aberrations and bone marrow micronucleus assays, respectively. Three concentrations of SL (16, 32, and 24?μg/mL) were used for the evaluation of its mutagenic potential in V79 cells and four doses (0.25, 0.50, 1.0, and 2.0?g/kg body weight) were used for Swiss mice. In the antimutagenicity assays, the different concentrations of SL were combined with the chemotherapeutic agent doxorubicin (DXR). HPLC analysis of SL gave contents of 6.57?%?±?0.41 of solasonine and 4.60?%?±?0.40 of solamargine. Total flavonoids and polyphenols contents in SL were 0.04 and 3.60?%, respectively. The results showed that not only SL exerted no mutagenic effect, but it also significantly reduced the frequency of chromosomal aberrations induced by DXR in both V79 cells and micronuclei in Swiss mice at the doses tested.     

多重荧光原位杂交检测多发性骨髓瘤复杂核型异常

目的探讨多重荧光原位杂交（M-FISH）技术在多发性骨髓瘤（MM）复杂核型异常（CCAs）检测中的价值。方法对5例常规R显带具有CCAs的MM患者应用MFISH确定复杂染色体的重排及标记染色体的组成。结粜明确了常规核型（CC）分析中的所有异常,共检出20种结构异常,其中缺失2种,易位18种,均为不平衡易位。最常累及的为14号染色体、1q的不平衡易位及6号染色体。结论对伴有CCAs的MM患者,M-FISH技术可以明确CC分析中复杂染色体异常,并发现和纠正CC分析中漏检及误检的异常,为MM的染色体异常研究提供了一种理想的方法。     

Protective effect of Cassia occidentalis extract on chemical-induced chromosomal aberrations in mice.

This study was conducted to determine the antimutagenic potential of aqueous extract of Cassia occidentalis against the chromosomal aberrations (CA) produced in vivo by benzo[a]pyrene (B[a]P) and cyclophosphamide (CP) in mice. Animals (male mice) were treated with three doses of plant extract (50 mg/kg, 250 mg/kg and 500 mg/kg) for 7 days prior to the administration of single dose of mutagens (B[a]P 125 mg/kg oral; CP 40 mg/kg i.p.). The results indicated that C. occidentalis was not genotoxic per se and exerted no other toxic signs and symptoms in treated animals. The chromosomal aberrations produced by B[a]P and CP were significantly reduced (p < 0.001) by C. occidentalis pre-treatment. Furthermore, animals treated with plant extract showed a reduced level of cytochrome P 450 (Cyt P 450) and elevated levels of glutathione S-transferase (GST) activity and glutathione content in the liver. It seems that C. occidentalis exerts its antimutagenic activity by modulating the xenobiotic activation and detoxification mechanisms.     

Effect of dietary fat on aflatoxin B1-induced chromosomal aberrations in mice

The effect on the frequency of aflatoxin B1 (AFB1)-induced chromosomal aberrations in bone marrow cells of mice fed diets containing increasing levels of sesame oil was investigated. Mice receiving either 9% or 12% sesame oil in their diet for 8 weeks presented a statistically increased AFB1-induced aberration rate as compared to those given a diet containing 3% sesame oil. These data suggest that the metabolism of a mutagen can be influenced by the dietary lipid intake of the test animal.     

Effects of propolis crude hydroalcoholic extract on chromosomal aberrations induced by doxorubicin in rats

Propolis has been reported to display a broad spectrum of biological activities such as anticancer, antioxidant, anti-inflammatory, antibiotic and antifungal properties, among others. There is great interest not only in the determination of the chemical composition of propolis but also in the understanding of the mechanisms related to its therapeutic actions. In this respect, the aim of the present investigation was to study the influence of both simultaneous (6, 12 and 24 mg/kg b. w.) and subacute (12 mg/kg b. w.) treatment with a crude hydroalcoholic extract of propolis on the frequency of chromosome aberrations induced by the chemotherapeutic agent doxorubicin (DXR) in Wistar rat bone marrow cells. HPLC analysis of the crude extract allowed the quantification of the phenolic compounds: caffeic acid, P-coumaric acid, aromadendrin 4'-methyl ether, 3-prenyl- P-coumaric acid (drupanin), isosakuranetin, kaempferide, 3,5-diprenyl- P-coumaric acid (artepellin C), baccharin and 2,2-dimethyl-6-carboxyethenyl-2 H-1-benzopyran. A total of 100 metaphase cells/animal were analyzed for chromosome aberration frequency and 1000 cells/animal were counted to obtain the mitotic index. The results showed that the dose of 12 mg propolis/kg b. w., administered either as a single dose or as subacute treatment, caused a statistically significant decrease in the frequency of chromosome damage induced by DXR compared to the group treated only with DXR. This reduction might be, in part, due to the presence of phenolic compounds in the studied propolis, which are able to capture free radicals produced by chemotherapeutic agents such as DXR.     

The phytoestrogens coumoestrol and genistein induce structural chromosomal aberrations in cultured human peripheral blood lymphocytes

The clastogenic potential of the phytoestrogens coumoestrol (COUM), genistein (GEN) and daidzein (DAI) has been studied in human peripheral blood lymphocytes in vitro. After exposure of the cultured lymphocytes to 50 or 75 μM COUM or 25 μM GEN for 6 h, a clear induction of structural chromosomal aberrations was observed by cytogenetic analysis. The major alterations were chromatid breaks, gaps and interchanges. In contrast, DAI did not induce chromosome aberrations even at 100 μM. These results, together with previously published reports on the induction of micronuclei and DNA strand breaks in cultured Chinese hamster V79 cells by COUM and GEN, but not DAI, suggest that some but not all phytoestrogens have the potential for genetic toxicity. Received: 13 August 1998 / Accepted: 26 October 1998     

Induction of chromosomal aberrations and sister chromatid exchanges by propane sultone in human lymphocytes in vitro

Genotoxicological investigation of 1,3-propane sultone was undertaken using human lymphocyte cultures as the test system. Concentrations greater than 1 mM induced appreciable chromosomal aberrations, which increased proportionally to the dose or the duration of treatment. It was also observed that treatment administered at 45 degrees C produced almost 3 times more abnormal cells than at 37 degrees C. The chemical also produced a significantly higher frequency of SCEs.     

Diesel exhaust particulate matter dispersed in a phospholipid surfactant induces chromosomal aberrations and micronuclei but not 6-thioguanine-resistant gene mutation in V79 cells

Diesel exhaust particulate material (DPM) was assayed for induction of chromosomal aberrations (CA), micronucleus (MN) formation, and 6-thioguanine-resistant (TG9 gene mutation in V79 cells as a dispersion in dipalmitoyl phosphatidylcholine (DPPC) in physiological saline, a simulated pulmonary surfactant. Filter-collected automobile DPM provided for the study was not organic solvent extracted, but was directly mixed into DPPC in saline dispersion as a model of pulmonary surfactant conditioning of a soot particle depositing in a lung alveolus. A statistically significant difference was found between treated and control groups at all concentrations tested in a CA assay. Assay for MN induction also gave a positive response: Above 50 microg/ml, the frequencies of micronucleated cells (MNC) were about 2 times higher than those in the control group. The forward gene mutation assay did not show a positive response when cells were treated with up to 136 microg DPM/ml for 24 h, as dispersion in DPPC in saline. Some comparison assays were run on direct dispersions of the DPM into dimethyl sulfoxide, with results equivalent to those seen with a DPPC-saline preparation: DPM in dimethyl sulfoxide (DMSO) was positive for MN induction but was negative for forward gene mutation in V79 cells. The positive clastogenicity results are consistent with other studies of DPM dispersed into DPPC-saline surfactant that have shown activity in mammalian cells for sister chromatid exchange, unscheduled DNA synthesis, and MN induction. The forward gene mutation negative results are consistent with studies of that assay applied to V79 cells challenged with DPM solvent extract.     

Induction of chromosomal aberrations by carbon nanotubes and titanium dioxide nanoparticles in human lymphocytes in vitro

Abstract

We examined if three commercially available nanomaterials – short singlewall carbon nanotubes (SWCNTs), short multiwall carbon nanotubes (MWCNTs) and nanosized titanium dioxide anatase (TiO₂; primary particle size <25 nm) – can induce structural chromosomal aberrations (CAs) in cultures of isolated human lymphocytes. To find a suitable sampling time, the cells were treated with 6.25–300 μg/ml of the nanomaterials for 24, 48 and 72 h. The 48-h treatment was the most effective, inducing a dose-dependent increase in chromosome-type CAs (all materials) and chromatid-type CAs (SWCNTs and TiO₂ anatase). The 72-h treatment yielded a positive result with SWCNTs. None of the treatments significantly affected cell count or the mitotic index. Our results suggest that with nanomaterials a continuous treatment for about two cell cycles is needed for CA induction, possibly reflecting access of nanomaterials to the nucleus during the first mitosis or delayed secondary genotoxic effect associated with the inflammatory process.     

Inhibition by plant phenols of benzo[a]pyrene-induced nuclear aberrations in mammalian intestinal cells: a rapid in vivo assessment method

The polycyclic aromatic hydrocarbon, benzo[a]pyrene, induced dose-related nuclear damage (micronuclei, pyknotic nuclei and karyorrhectic bodies) in colonic epithelial cells of C57BL/6J mice within 24 hr when administered intrarectally in single doses of 0-200 mg/kg body weight. This damage was reduced when mice ingested the plant phenols, caffeic, ferulic and ellagic acids, and quercetin at levels of 4% or BHA at 2% (w/w) in the diet for 1 wk prior to the benzo[a]pyrene challenge (100 mg/kg body weight). Benzo[a]pyrene-induced nuclear damage was not significantly inhibited by 4% curcumin under similar conditions. The inhibition of nuclear damage is consistent with reported antimutagenic effects for these agents in vitro and in longer term animal studies. The procedure described here may provide a rapid in vivo method for assessing the potential of natural products to inhibit the carcinogenic process.     

Assessment of the ability of Imazaquin herbicide to induce chromosomal aberrations in vitro in cultured Chinese hamster ovary cells and micronuclei in vivo in mice.

The agricultural chemicals marketed to increase food production may not only combat pests and weeds but also present toxic properties and cause genetic damage to the fauna and flora. The Imazaquin herbicide (Scepter 70 DG-Cyanamid) has been widely used in soybean fields in Paraná (Brazil), but information on its genotoxicity is scarce. Thus, in vivo and in vitro studies were carried out to assess the possible clastogenic effect of this herbicide on eukaryote cells. In the in vitro studies, the Chinese hamster ovarian cell lines CHO-K1 (wild) and CHO xrs-5 (mutant) were treated at the three phases of the cell cycle (G1, S and G2) for chromosome aberration (CA) analysis. The in vivo assessment was carried out by the micronucleus test (MN) on Swiss mice (Mus musculus) bone marrow cells. The herbicide did not induce a significant increase in the CA frequency in any of the treatments. No statistically significant differences were observed in the MN frequencies among the groups treated with the herbicide and the negative control. From the test system used in this study, we can conclude that the Imazaquin herbicide did not act as a clastogenic agent either in vitro or in vivo.     

Assessment of genotoxic damage in nurses occupationally exposed to antineoplastics by the analysis of chromosomal aberrations

To estimate the genotoxic risk of occupational exposure to antineoplastic drugs, chromosomal aberration (CAs) frequencies in peripheral lymphocytes were determined for 20 nurses handling antineoplastics and 18 referents matched for age and sex. Urinary cyclophosphamide (CP) excretion rates, which are used as a marker for drug handling, were also measured on these nurses. We have observed significant frequencies of CAs (about 2.5-fold increase) including chromatid breaks, gaps, and acentric fragments for nurses handling antineoplastics as compared to control subjects (p < 0.05, p < 0.01, excluding and including gaps, respectively). The mean value of CP excretion rate for 12 nurses was 1.63 microg/24 h, suggesting that when the nurses handled CP (and other antineoplastic drugs) this particular compound was absorbed. Our study has shown that increased genetic damage was evident in nurses, at population level, due to occupational exposure to antineoplastics. Until the effects of handling antineoplastics from low-level exposure are known, it will be important to keep the exposure to a minimum.     

Induction of chromosomal aberrations and micronuclei by 2-hydroxy-4-methoxybenzophenone (oxybenzone) in human lymphocytes

Oxybenzone or benzophenone-3 (2-hydroxy-4-methoxybenzophenone; BP-3) is a filter used in a variety of personal care products for protection of human skin and hair from damage by ultraviolet radiation. BP-3 is suspected to exhibit endocrine disruptive properties. Indeed, it was found to be able to interact with the endocrine system causing alteration of its homeostasis, with consequent adverse health effects. Moreover, it is ubiquitously present in the environment, mostly in aquatic ecosystems, with consequent risks to the health of aquatic organisms and humans. In the present study, we analyzed the cytogenetic effects of BP-3 on human lymphocytes using in vitro chromosomal aberrations and micronuclei assays. Blood samples were obtained from five healthy Italian subjects. Lymphocyte cultures were exposed to five concentrations of BP-3 (0.20, 0.10, 0.05, 0.025, and 0.0125?μg/mL) for 24 and 48?h (for chromosomal aberrations and micronuclei tests, respectively). The concentration of 0.10?µg/mL represents the acceptable/tolerable daily intake reference dose established by European Union, whereas 0.20, 0.05, 0.025, and 0.0125?µg/mL represent multiple and sub-multiple of this concentration value. Our results reported cytogenetic effects of BP-3 on cultured human lymphocytes in terms of increased micronuclei and chromosomal aberrations’ frequencies at all tested concentrations, including concentrations lower than those established by European Union. Vice versa, after 48-h exposure, a significant reduction of the cytokinesis-block proliferation index value in cultures treated with BP-3 was not observed, indicating that BP-3 does not seem to produce effects on the proliferation/mitotic index when its concentration is equal to or less than 0.20?μg/mL.