Effects of sorbic acid and sorbic acid-nitrite in vivo on bone marrow chromosomes of mice

The effect of sorbic acid alone and in combination with sodium nitrite has been studied on bone marrow chromosomes of mice following 30 days oral treatment. Bone marrow of mice exposed to sorbic acid (15 mg/kg) and sorbic acid nitrite (7.5-1 mg/kg) showed an increase in mitotic index indicating that the drugs had an effect on spindle apparatus. Sorbic acid effected spindle activity but did not damage chromosomes, whereas nitrite itself was clastogenic. However, a combination of half the concentration each of sorbic acid (15 mg/kg) and sodium nitrite (2 mg/kg) together gave synergistic effects, which may be ascribed to the formation of some genotoxic compound in vivo.     

Sister chromatid exchanges produced by imipramine and desipramine in mouse bone marrow cells treated in vivo

Imipramine and desipramine are two widely used tricyclic antidepressants which have shown conflicting results in regard to their in vitro genotoxic evaluation. The aim of this investigation was to determine the capacity of these compounds to induce in vivo sister-chromatid exchanges (SCEs) in mouse bone marrow cells. For each compound, the animals were organized in five groups constituted by five individuals. They were intraperitoneally (ip) administered with the test substances as follows: a negative control group treated with 0.4 ml of distilled water, a positive control group administered with cyclophosphamide (70 mg/kg), three groups treated with imipramine (7, 20 and 60 mg/kg), and three other groups treated with desipramine (2, 20 and 60 mg/kg). The general procedure included the subcutaneous implantation to each mouse of a 5-bromodesoxyuridine tablet (45 mg), and 1 h later, the administration of the chemicals involved. Twenty-one hours after the tablet implantation, the mice received colchicine, and 3 h later their femoral bone marrow was obtained in KCL, fixed, and stained with the Hoechst-Giemsa method. The results showed that both compounds were SCE inducers, starting from the second tested dose. The response of these compounds was dose-dependent, and showed that the highest tested dose increased about four times the SCE control level. The cellular proliferation kinetics was not affected by the chemicals, and the mitotic indexes were slightly diminished with the highest dose. These results indicate an in vivo genotoxic potential for both chemicals, and suggest that it is pertinent to follow their evaluation in other models.     

Sister chromatid exchange induced by 'pan masala' (a betel quid ingredient) in male mice in vivo

Sister chromatid exchange (SCE) induced in vivo by 'pan masala', a betel quid ingredient, was studied in male mice. The mice were injected ip with an aqueous suspension of pan masala at doses of 5, 12.5, 25, 50, 100 or 200 mg pan masala/kg body weight. A significant dose-related increase in SCE was observed (Cochran-Armitage trend test). The minimum effective dose was 25 mg/kg. The two highest doses caused significant delays in the cell cycle. These results indicate that pan masala is a potential DNA-damaging agent and cytotoxic to bone marrow cells.     

Sister chromatid exchange frequencies induced in vivo and in vitro by the residues of brandy

We obtained 6.93 g/l of residues of brandy after distillation and lyophilization of the beverage, and studied the genotoxic potential of this substance by scoring sister chromatid exchanges (SCE) and evaluating cellular proliferation kinetics. For the in vitro study we tested 5, 10, 15, and 21 mg/ml of the residue in human lymphocyte cultures, and found a genotoxic response with the highest two doses as well as a delay of the cell cycle duration. For the in vivo study we used the mouse bone marrow system and tested 50, 200, 400, 800, and 1600 mg/kg. The results showed a significant increase of the SCE with the highest three doses without any modification of the cell cycle. The residues of brandy seem to be moderate inducers of SCE, as a doubling of the effect above the base line was not observed.     

Sister chromatid exchanges in breast cancer patients who underwent chemotherapy

The study aimed to determine the effects of cytostatic and genotoxic drugs used to treat breast cancer on sister chromatid exchange (SCE). SCE values were examined in 25 female patients with breast cancer in pre-treatment, treatment process and remission period as well as in 22 nonsmoker women via peripheral blood culture technique. The SCE values of patient and control group were analyzed via "Mann-Whitney U test". Whilst SCE values of patient group ??were 8.25 ± 3.67, 10.19 ± 2.95 and 11.52 ± 3.33 in pre-treatment, treatment process and remission periods respectively, it was 7.01 ± 1.24 in control group. When overall SCE values of patients group in pre-treatment period were compared with those of control group, no significant difference was observed (p > 0.05), whereas highly significant differences were observed between treatment process and remission period of patient groups and control group in terms of SCE values (p < 0.01). If patients are exposed to any cytostatic and clastogenic drugs, the increase in the exchange values was considered remarkable. These findings reinforced the availability of sister chromatid exchange technique in directing of treatment and monitoring the genetic abnormalities caused by genomic instability which may occur due to the drugs used for treatment.     

Sister chromatid exchanges in lymphocytes of nurses handling antineoplastic drugs

The effects of handling antineoplastic drugs were examined in a group of 23 nurses working in the hematology and oncology departments of different university hospitals in Ankara and in a group of 50 unexposed controls. The cytogenetic repercussions of exposure were assessed by examining sister chromatid exchanges (SCEs) in circulating lymphocytes which result from the breakage and rejoining of DNA at apparently homologous sites on the 2 chromatids of a single chromosome. A significant increased frequency of SCE is observed in nurses in daily contact with antineoplastics (n = 23, mean SCEs/cell +/- SE 6.5 +/- 0.2) as compared to a group of controls (n = 50, mean SCEs/cell 5.2 +/- 0.2). The nurses who smoked also had a higher SCE frequency (n = 15, mean SCEs/cell 7.0 +/- 0.3) than non-smokers, (n = 8, mean SCEs/cell 5.5 +/- 0.3). A significant increase (P less than 0.001) in the mean number of SCE was found for non-smoking nurses as compared to non-smoking controls (n = 27, mean SCEs/cell 4.1 +/- 0.2).     

Induction of sister chromatid exchanges by 2,4-dichlorophenoxyacetic acid in somatic and germ cells of mice exposed in vivo.

2,4-dichlorophenoxyacetic acid (2,4-D) is one of the most widely used selective herbicides throughout the world; however, the studies that have been conducted to establish its genotoxic potential have given conflicting results. The aim of this investigation was to determine whether the herbicide increases the frequency of sister chromatid exchanges (SCEs) in bone marrow and spermatogonial cells of mice exposed in vivo. The experiment included an oral administration of 2,4-D to three groups of mice (50,100 and 200 mg/kg), as well as to a control group of animals administered with distilled water, pH 10.5 and another group injected with cyclophosphamide (50 mg/kg). In somatic cells, the results showed a significant SCE increase with the two high doses tested, a response that was manifested in a dose-dependent manner. With regard to the mitotic index and the cell proliferation kinetics, there were no modifications exerted by 2,4-D; however, cyclophosphamide induced cytotoxic damage and a cell-cycle delay. With respect to the germ cells, the genotoxic results were similar to those described earlier; that is, there was a significant SCE increase induced by the two high 2,4-D doses tested and a higher genotoxic damage was observed in the animals treated with cyclophosphamide. Our investigation established that 2,4-D is a moderate genotoxicant in mice treated in vivo with high doses, and suggests a minor hazard for humans in the present conditions of its use.     

Sister chromatid exchanges, proliferating rate index, and micronuclei in biomonitoring of internal exposure to vinyl chloride monomer in plastic industry workers

The frequency of micronuclei (MN), sister chromatid exchange (SCEs), and the proliferating rate index in peripheral blood lymphocytes from 93 individuals were measured. Fifty-two of the individuals were workers in the plastics industry where they were exposed to vinyl chloride monomer while the remaining 41 individuals served as a control group. In our results, an increase of SCEs and MN, as well as inhibited cell kinetics, was observed in the group of exposed workers. Of the tests used, SCE was found to be the most sensitive endpoint for indicating a biological response. However, since methods for restricting the MN analysis to only cells at risk (i.e., second generation interphase cells) were not used, this statement requires verification.     

Effects of sorbic acid and its salts on chromosome aberrations, sister chromatid exchanges and gene mutations in cultured Chinese hamster cells

The ability of sorbic acid and its potassium and sodium salts to induce chromosome aberrations, sister chromatid exchanges (SCE) and gene mutations in cultured Chinese hamster V79 cells was examined. Sodium sorbate caused significant induction of chromosome aberrations and SCE, and also induced 6-thioguanine-resistant mutations in a dose-dependent manner. The clastogenic potency of sodium sorbate was found to be less than one hundredth of that of the potent clastogen N-methyl-N'-nitro-N-nitrosoguanidine. The induction of SCE by sodium sorbate was twice the control level, whereas that by methyl methanesulphonate, a potent inducer of SCE, was 14 times the control level. The mutagenic potency of sodium sorbate was less than one-tenth that of ethyl methanesulphonate, a potent inducer of mutation, when compared at an equitoxic level. Sorbic acid and its potassium salt induced chromosome aberrations, but only at the highest doses tested. These compounds also induced 1.2 times the control level of SCE, but neither compound induced 6-thioguanine-resistant mutations. The cytogenetic activity of sodium sorbate was concluded not to be due to the effect of osmotic pressure or an impurity. These results indicate that sodium sorbate is a genotoxic agent, although its potency seems to be weak, and that sorbic acid and potassium sorbate are less genotoxic than the sodium salt.     

Inhibition of mitomycin C-induced sister chromatid exchanges by vitamin C in vivo.

The aim of this experiment was to test the modulation of genotoxicity produced by vitamin C (V-C) challenged against mitomycin C (MMC) in vivo, by analyzing the sister chromatid exchanges (SCE) and cell proliferation kinetics. We used the mouse bone marrow cytogenetic method, and tested three dosages of V-C (3, 5, and 7 g/kg of body weight), along with the appropriate positive (2 mg MMC/kg body weight) and negative V-C controls. The results showed that V-C caused a strong inhibition of SCEs induced by MMC in the three dosages administered. The highest dose (7 g/kg) caused an SCE inhibition of 70.02%, while the lower ones caused an inhibition of 54.61% and 52.30%, respectively. It was also clear that V-C per se does not increase the level of SCEs in mouse bone marrow cells. On the other hand, V-C induced a slight decrease in cell proliferation that was stronger when combined with MMC. Our data suggest that V-C effectively inhibit the SCE damage in vivo, but caution must be taken because of the observed cytotoxicity.     

Sister-chromatid exchanges induced by disulfiram in bone marrow and spermatogonial cells of mice treated in vivo.

Disulfiram is a widely used drug to treat alcoholism due to its capacity to inhibit the metabolism of acetaldehyde; however, its genotoxic potential is not well known. Thus, the aim of this investigation was to determine whether the chemical may induce sister-chromatid exchanges (SCEs) in an in vivo study using mouse bone marrow and spermatogonial cells. We used doses of 200, 400 and 800 mg/kg body weight and compared the obtained data with the values determined in a negative control group as well as with a positive control group (cyclophosphamide, 50 mg/kg). The results in both systems indicated a weak genotoxic response by the chemical. In the case of bone marrow, a significant SCE level was achieved only with the high tested dose, but in spermatogonial cells the three doses tested showed a significant difference with respect to the negative control. No significant alterations in the mitotic index or in the cell proliferation kinetics were observed in somatic cells. Concerning the effect of cyclophosphamide, an increase in the level of SCEs was observed in both types of cells, reaching more than three times the values obtained in their respective control groups.     

Effects of smoking on spontaneous and induced sister chromatid exchanges in lymphocytes

Spontaneous and mitomycin C-induced sister chromatid exchanges (SCEs) in lymphocytes were analyzed in 24 non-smokers and 24 sex- and age-matched smokers. Mean spontaneous SCE frequency for non-smokers was 9.8 SCEs/cell, and that for smokers was 11.5 SCEs/cell. The difference was statistically significant (P less than 0.001 by t-test). These results suggest that spontaneous SCE frequency in lymphocytes is useful for evaluation of biological effects of environmental mutagens. However, we could not find any effects of smoking on the sensitivities of lymphocytes to mitomycin C in vitro. The effects of mutagens on humans may be independent of one another.     

Chromosomal aberrations,sister chromatid exchanges,and micronuclei in lymphocytes of oncology department personnel handling anti-neoplastic drugs

Objective: Concern exists regarding the possible hazards to the personnel handling anti-neoplastic drugs. The purpose of the present study was to assess the genotoxicity induced by anti-neoplastic agents in oncology department personnel. Materials and methods: To do this, the frequency of chromosomal aberrations (CAs) induced in peripheral blood lymphocytes was assessed at G₀ phase of the cell cycle using metaphase analysis, cytokinesis block-micronucleus (MN) assay and sister chromatid exchange (SCE) assay. These cytogenetic end points were measured among 71 nurses in oncology department and 10 drugstore personnel handling and preparing anti-neoplastic drugs. The results were compared to those of 74 matched nurses for age and sex not exposed to any anti-neoplastic agents. Results: There was no significant difference between the age of study subjects and control group (p?>?0.05). The results showed that the mean frequency of cytogenetic damages in terms of CAs [chromatid breaks (p?=?0.01), chromosome breaks (p?=?0.005), total CAs (p?=?0.001)], MN formation (p?=?0.001), and SCE (p?=?0.004) in lymphocytes of personnel handling anti-neoplastic drugs were significantly higher than those in control unexposed group. Conclusion: Results of the present study demonstrate the cytogenetic damage in peripheral blood lymphocytes of oncology department personnel. Suitable training and proper knowledge when handling anti-neoplastic drugs are emphasized to avoid potential health hazards caused by cytostatic agents.     

Sister chromatid exchange in regenerating liver and bone marrow cells of mice exposed to styrene

Following exposure of BDF₁ males to 565 ± 15.8 ppm styrene for 4 days (6 hr/day), sister chromatid exchange frequencies were analyzed simultaneously in regenerating liver and bone marrow cells from exposed mice. Comparisons were made with nonexposed controls. Regenerating liver as well as bone marrow cells showed a three-to four fold increase relative to the control.     

Induction of sister chromatid exchanges in Chinese hamster cells by the reducing agents bisulfite and ascorbic acid

Sister chromatid exchanges (SCEs) are induced in Chinese hamster cells by a 2--3-h exposure to ascorbic acid or bisulfite in the concentration range 10(-4)--10(-2) M. This activity of these 2 chemicals was intensified when cell cultures were exposed to each agent for longer time periods (24 h). The divalent metal cation, Cu2+, was effective in potentiating the ability of ascorbic acid to induce SCEs and toxicity, suggesting that the autooxidation of ascorbic acid was involved in this action. The ability of sodium bisulfite to induce SCEs was not affected by variation in the concentration of 5'-bromodeoxyuridine used as a labelling compound. This was interpreted as supporting the view that bisulfite, not a synergistic reaction between bisulfite and BrdU, was responsible for the elevated SCE levels.     

Assessment of the in vivo genotoxicity of vanadate: analysis of micronuclei and DNA damage induced in mice by oral exposure

Vanadium compounds are able to interact with living cells exerting a variety of biological effects. The pentavalent form is the most stable and toxic form of the element. In systems in vitro pentavalent vanadium is an effective genotoxic agent, inducing DNA damage and chromosome malsegregation at low doses. On the other hand, no adequate in vivo data are available for the characterization of the genotoxic hazard following oral intake, the most relevant route of human exposure. In this study, the genotoxic effects produced by the oral intake of sodium ortho-vanadate (Na(3)VO(4)) were investigated. Male CD-1 mice were treated for 5 weeks with a range of concentrations of Na(3)VO(4) in drinking water (0.75-1500 mg/l). Both micronuclei and primary DNA lesions as detected by comet assay were assessed in several tissues. Statistically significant increases of micronuclei in bone marrow were observed in mice receiving the two highest concentrations of Na(3)VO(4) (750 and 1500 mg/l). A significant increase of comet tail length was observed in splenocytes of mice receiving Na(3)VO(4) at 1500 mg/l, whereas no effect was observed in bone marrow and testis cells. No treatment-related effect on sperm chromatin structure or on testis cell population was observed. The determination of vanadium content in mouse tissues at the end of treatment highlighted a very low internal exposure, especially in soft tissues. Overall, the results obtained indicate that the genotoxic activity of pentavalent vanadium is expressed in vivo only following high dose exposure, possibly as a consequence of the poor bioavailability of the element.     

Sister chromatid exchange in murine alveolar macrophages,bone marrow,and regenerating liver cells induced by styrene inhalation

Exposure concentration-dependent increases in sister chromatid exchange frequencies were exhibited in simultaneously harvested alveolar macrophages, bone marrow, and regenerating liver cells of mice exposed to styrene concentrations of 104, 387, 591, and 922 ppm. Exposures were 6 hr/day for 4 days. The highest concentration was also employed for 1- and 2-day exposures. At the concentrations employed there were no significant differences in sister chromatid exchange frequencies among the different cell types studied or between hepatectomized mice and nonhepatectomized mice. However, hepatectomized mice were more sensitive than nonhepatectomized mice to the cellular toxicity of styrene.     

Absence of an effect of lead acetate on sperm morphology,sister chromatid exchanges or on micronuclei formation in rabbits

The influence of lead on sperm morphology, sister chromatid exchanges or on micronuclei formation was studied on male rabbits after exposure to doses of 0, 0.25, and 0.50 mg lead acetate/kg body weight subcutaneously injected three times a week during 14 weeks, each on a group of five rabbits. At the end of exposure phase the lead in blood concentrations of the three groups of rabbits were 0.32, 2.57, and 2.97 mol/l respectively. The results did not show any evidence of treatment related effects on sperm count or on morphologic abnormalities of the sperms, neither on the histopathology of the testis. Statistical analysis of the number of sister chromatid exchanges per metaphase in lymphocytes indicated no differences between the groups. Also no dose dependent effect was observed on the relative number of micronuclei in bone marrow erythrocytes. The different susceptibility to lead in different organ systems of the rabbits was discussed.     

Evaluation of genotoxicity of clofazimine, an antileprosy drug, in mice in vivo. III. Sister chromatid exchange analysis in bone marrow cells

The potential genotoxicity of an antileprosy drug, clofazimine, was evaluated in mice in an in vivo model by sister chromatid exchange (SCE) analysis. Three different dose levels (4, 20 and 40 mg/kg) were tested, and the animals were treated once daily for 15 days. Sister chromatid differential staining was done by BrdU-tablet implantation and FPG technique. All the doses tested here elevated the SCE frequencies significantly and the increases showed a significant positive correlation with the doses. The results confirm our earlier findings based on metaphase analysis and micronucleus test in the same species.