An improved chemical substitute for fetal calf serum for the micronucleus test

Study of Mutagenic and Antitoxic Properties of Gentabiferon-B

The combination of immunomodulators and antibiotics in the treatment of animals with diseases of bacterial etiology is one of the effective strategies for animal therapy. The drug gentabiferon-B combines antibiotic gentamicin and species-specific (bovine) recombinant interferons -α and -γ. The study aimed to evaluate the effect of course application of gentabiferon-B on the cytogenetic stability of bone marrow cells of outbred mice after administering mitomycin C (MMC). The proportion of polychromatophilic erythrocytes in the bone marrow was assessed. There was no effect of gentabiferon-B on the frequency of polychromatophilic erythrocytes with micronuclei in both healthy animals and mice with MMC-induced cytogenetic instability. The course application of gentabiferon-B before the administration of MMC led to an increase in the proportion of polychromatophilic erythrocytes (46.03±2.61%) which was non-significantly different than the negative control group. The administration of MMC alone caused a decrease in the proportion of polychromatophilic erythrocytes to 33.33±1.83%. The antitoxic effect of gentabiferon-B led to an increase in the level of polychromatophilic erythrocytes by 38.1% compared to the group that received only MMC. Studies have shown that gentabiferon-B does not have mutagenic activity and anticlastogenic properties, however, it reduces the toxic effect of MMC. In conclusion, it is indicative that gentabiferon-B has antitoxic properties and can be safely used in animal therapy.

N-acetyl-cysteine in combination with celecoxib inhibits Deoxynivalenol induced skin tumor initiation via induction of autophagic pathways in swiss mice

Deoxynivalenol is a trichothecene mycotoxin which naturally contaminates small grain, cereals intended for human and animal consumption. Investigations for dermal toxicity of DON has been needed and highlighted by WHO. Previous studies on dermal toxicity suggest that DON has DNA damaging potential leading to skin tumor initiation in mice skin. However, considering its toxicological manifestations arising after dermal exposure, strategies for its prevention/protection are barely available in literatute. Collectively, our study demonstrated that N-acetylcysteine (NAC), precursor of glutathione, significantly alters the genotoxic potential of DON. Further NAC in combination with Celecoxib (CXB) inhibits tumor growth by altering antioxidant status and increasing autophagy in DON initiated Swiss mice. Despite the broad spectrum use of CXB, its use is limited by the concerns about its adverse effects on the cardiovascular system. Serum parameters and histology analysis revealed that CXB (2 mg) when applied topically for 24 weeks did not impart any cardiovascular toxicity which could be because skin permeation potential of CXB was quite low when analyzed through HPLC analysis. Although the anticancer effects of CXB and NAC have been studied, however, the combination of NAC and CXB has yet not been explored for any cancer treatment. Therefore our observations provide additional insights into the therapeutic effects of combinatorial treatment of CXB and NAC against skin tumor prevention. This approach might form a novel alternative strategy for skin cancer treatment as well as skin associated toxicities caused by mycotoxins such as DON. This combinatorial approach can overcome the limitations associated with the use of CXB for long term as topical application of the same seems to be safe in comparison to the oral mode of administration.

Effect of Zingiber officinale on some biochemical parameters and cytogenic analysis in lead-induced toxicity in experimental rats

Exposure to toxic elements is greatly unavoidable in our daily activities due to several routes of coming in contact with these elements. Thus lead (Pb), is one of the major causes of health hazard in human. In this study, evaluation of Zingiber officinale as mitigating measure against Pb induced biochemical and cytogenic toxicity in albino rats was investigated. Experimental rats were grouped into five with five animals per group, group I serves as control and groups 2-5 were induced intraperitoneal with lead acetate dissolved in distilled water at 3 mg/kg body weight whereas group 3-5 were orally administered with 200 mg/kg vitamin C, 200 mg/kg, and 100 mg/kg of Z. officinale, respectively for 7 d. The obtained results show that aspartate aminotransferase (AST), alkaline phosphatase (ALP), lipid peroxidation, urea, creatinine, bilirubin, and gamma-glutamyl transferase (GGT) were significantly increased (p < 0.05) and catalase (CAT) were reduced progressively in Pb alone induced rats. Hematological parameters showed a progressive reduction (p < 0.05) in lead acetate alone rats. There were significant changes in micronuclei (MN), chromosomal aberrations (CA) frequency, and oxidative damages in the bone marrow cells from lead acetate alone induced rats, although, mitotic index scores in these cells were reduced gradually (p < 0.05). The altered parameters were significantly reversed toward the levels observed in normal control rats administered with vitamin C and aqueous extract of Z. officinale. Hence, these results suggest that Z. officinale roots might contain therapeutic potential that can ameliorate the hazard effect of lead acetate poison.

Aqueous extract of Carica papaya Linn. roots potentially attenuates arsenic induced biochemical and genotoxic effects in Wistar rats

In Africa, the fruit, leaf, seed and roots of Carica papaya Linn. are generally used to treat a variety of diseases such as malaria, cancer, and cardiovascular diseases. In this study, we evaluated the protective potentials of aqueous extract of C. papaya roots on arsenic-induced biochemical and genotoxic effects in Wistar rats. Rats were induced intraperitoneal with sodium arsenate (dissolved in distilled water at 3 mg/kg body weight) for 21 days and the animals were administered simultaneously with 200 mg/kg body weight vitamin C, 100 and 150 mg/kg body weight of the C. papaya Linn. root aqueous extract once daily for three weeks. Results obtained reveals that activities of plasma 8-OHdG, serum lipids concentration, atherogenic index (AI), coronary artery index (CRI), aspartate transaminase, alanine transaminase, alkaline phosphatase, total bilirubin levels were elevated significantly (p < 0.05) and catalase, glutathione peroxidase, superoxide dismutase, plasma hematological profile were progressively reduced (p < 0.05) in arsenic-alone exposed rats. Significant increase in the quantity of chromosomal aberrations (CA), micronuclei (MN) frequency, oxidative damages in the bone marrow cells from arsenic alone rats was observed. Though, mitotic index scores in these cells were progressively reduced (p < 0.05). In animals administered with aqueous extract of C. papaya roots and vitamin C, the altered parameters were significantly recovered towards the levels observed in normal control rats. These results suggest that aqueous C. papaya roots preparations might have therapeutic potential as a supplement that can be applied in arsenic poisoning.

Cytogenetic evaluation of functionalized single-walled carbon nanotube in mice bone marrow cells

With their unique structure and physicochemical properties, single\-walled carbon nanotubes (SWCNTs) have many potential new applications in medicine and industry. However, there is lack of detailed information concerning their impact on human health and the environment. The aim of this study was to assess the effects, after intraperitoneal injection of functionalized SWCNTs (f-SWCNT) on the induction of reactive oxygen species (ROS), frequency of structural chromosomal aberrations (SCA), frequency of micronuclei induction, mitotic index, and DNA damage in Swiss-Webster mice. Three doses of f-SWCNTs (0.25, 0.5, and 0.75 mg/kg) and two controls (negative and positive) were administered to mice, once a day for 5 days. Bone marrow and peripheral blood samples were collected 24 h after the last treatment following standard protocols. F-SWCNT exposure significantly enhanced ROS, increased (p < 0.05) the number of SCA and the frequency of micronucleated cells, increased DNA damage, and decreased the mitotic index in exposed groups compared to negative control. The scientific findings reported here suggest that purified f-SWCNT have the potential to induce oxidative stress mediated genotoxicity in Swiss-Webster mice at higher level of exposure. Further characterization of their systemic toxicity, genotoxicity, and carcinogenicity is also essential. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1091-1102, 2016.

Ameliorative effect of flaxseed oil against thiacloprid-induced toxicity in rats: hematological, biochemical, and histopathological study

The present study was carried out to evaluate the hematological, biochemical, and histopathological changes due to thiacloprid toxicity, and the potential protective role of flaxseed oil in male Wistar albino rats. Subacute thiacloprid intoxication induced a significant increase in RBCs, Hb, PCV, and WBCs count, and bone marrow micronucleus (MN) formation. Moreover, there was a significant increase in serum biochemical parameters related to hepatic injury: alanine aminotransferase (ALT) and alkaline phosphatase (ALP). Serum total protein and albumin levels were significantly reduced. Thiacloprid increases tumor necrosis factor-alpha (TNF-α) and interleukine-2(IL-2). There was a significant decrease in glutathione-S-transferase, while the lipid peroxidation (MDA) and cytochrome P450 activity were significantly increased. Flaxseed oil coadministration partially retrieved the changes in all studied parameters. Thiacloprid induced histopathological liver damage, which was minimized as a result of flaxseed oil treatment. In general, it was concluded that, flaxseed oil able to protect against thiacloprid-induced hepatoxicity.

Genotoxicity study of silver nanoparticles in bone marrow cells of Sprague-Dawley rats

The antimicrobial properties of silver nanoparticles (Ag-NPs) have resulted in their extensive application in consumer and health care products. Although Ag-NPs have great potential benefits, their side effects are unknown and seem inevitable due to their ability to reach the nucleus and damage genetic material. This study aimed to determine genotoxic potential of Ag-NPs using mitotic index (MI), DNA damage (comet assay), structural chromosome aberrations (SCA), micronuclei (MN) formation as genetic endpoints and induction of reactive oxygen species (ROS) as oxidative stress endpoint in bone marrow of Sprague-Dawley rats. Four groups of five male rats were orally administered Ag-NPs, once a day for five days with doses of 5, 25, 50, 100, mg/Kg. A control group was also made of five rats. Bone marrow samples were collected 24 h after the last treatment following standard protocols. Ag-NPs exposure significantly increased (p < 0.05) the induction of ROS, number of SCA, the frequency of micro-nucleated cells, damaged the DNA and decreased the mitotic index compared to negative control. The results suggest that Ag-NPs may have the potential to induce oxidative stress mediated genotoxicity in rats. Further characterization of their genotoxicity and also their potential health implications should be monitored regularly.

Extremely low-frequency magnetic field enhances the therapeutic efficacy of low-dose cisplatin in the treatment of Ehrlich carcinoma

The present study examines the therapeutic efficacy of the administration of low-dose cisplatin (cis) followed by exposure to extremely low-frequency magnetic field (ELF-MF), with an average intensity of 10 mT, on Ehrlich carcinoma in vivo. The cytotoxic and genotoxic actions of this combination were studied using comet assay, mitotic index (MI), and the induction of micronucleus (MN). Moreover, the inhibition of tumor growth was also measured. Treatment with cisplatin and ELF-MF (group A) increased the number of damaged cells by 54% compared with 41% for mice treated with cisplatin alone (group B), 20% for mice treated by exposure to ELF-MF (group C), and 9% for the control group (group D). Also the mitotic index decreased significantly for all treated groups (P < 0.001). The decrement percent for the treated groups (A, B, and C) were 70%, 65%, and 22%, respectively, compared with the control group (D). Additionally, the rate of tumor growth at day 12 was suppressed significantly (P < 0.001) for groups A, B, and C with respect to group (D). These results suggest that ELF-MF enhanced the cytotoxic activity of cisplatin and potentiate the benefit of using a combination of low-dose cisplatin and ELF-MF in the treatment of Ehrlich carcinoma.

Arsenic-induced biochemical and genotoxic effects and distribution in tissues of Sprague-Dawley rats

Arsenic (As) is a well documented human carcinogen. However, its mechanisms of toxic action and carcinogenic potential in animals have not been conclusive. In this research, we investigated the biochemical and genotoxic effects of As and studied its distribution in selected tissues of Sprague-Dawley rats. Four groups of six male rats, each weighing approximately 60 ± 2 g, were injected intraperitoneally, once a day for 5 days with doses of 5, 10, 15, 20 mg/kg bw of arsenic trioxide. A control group was also made of 6 animals injected with distilled water. Following anaesthetization, blood was collected and enzyme analysis was performed by spectrophotometry following standard protocols. At the end of experimentation, the animals were sacrificed, and the lung, liver, brain and kidney were collected 24 h after the fifth day treatment. Chromosome and micronuclei preparation was obtained from bone marrow cells. Arsenic exposure significantly increased (p<0.05) the activities of plasma alanine aminotransferase-glutamate pyruvate transaminase (ALT/GPT), and aspartate aminotransferase-glutamate oxaloacetate transaminase (AST/GOT), as well as the number of structural chromosomal aberrations (SCA) and frequency of micronuclei (MN) in the bone marrow cells. In contrast, the mitotic index in these cells was significantly reduced (p<0.05). These findings indicate that aminotransferases are candidate biomarkers for arsenic-induced hepatotoxicity. Our results also demonstrate that As has a strong genotoxic potential, as measured by the bone marrow SCA and MN tests in Sprague-Dawley rats. Total arsenic concentrations in tissues were measured by inductively coupled plasma mass spectrometry (ICP-MS). A dynamic reaction cell (DRC) with hydrogen gas was used to eliminate the ArCl interference at mass 75, in the measurement of total As. Total As doses in tissues tended to correlate with specific exposure levels.

Assessment of genotoxic and cytotoxic hazards in brain and bone marrow cells of newborn rats exposed to extremely low-frequency magnetic field

The present study aimed to evaluate the association between whole body exposure to extremely low frequency magnetic field (ELF-MF) and genotoxic , cytotoxic hazards in brain and bone marrow cells of newborn rats. Newborn rats (10 days after delivery) were exposed continuously to 50 Hz, 0.5 mT for 30 days. The control group was treated as the exposed one with the sole difference that the rats were not exposed to magnetic field. Comet assay was used to quantify the level of DNA damage in isolated brain cells. Also bone marrow cells were flushed out to assess micronucleus induction and mitotic index. Spectrophotometric methods were used to measure the level of malondialdehyde (MDA) and the activity of glutathione (GSH) and superoxide dismutase (SOD). The results showed a significant increase in the mean tail moment indicating DNA damage in exposed group (P < 0.01, 0.001, 0.0001). Moreover ELF-MF exposure induced a significant (P < 0.01, 0.001) four folds increase in the induction of micronucleus and about three folds increase in mitotic index (P < 0.0001). Additionally newborn rats exposed to ELF-MF showed significant higher levels of MDA and SOD (P < 0.05). Meanwhile ELF-MF failed to alter the activity of GSH. In conclusion, the present study suggests an association between DNA damage and ELF-MF exposure in newborn rats.

Comparative study of the clastogenicity of functionalized and nonfunctionalized multiwalled carbon nanotubes in bone marrow cells of Swiss-Webster mice

The development of nanotechnologies may lead to environmental release of nanomaterials that are potentially harmful to human health. Among the nanomaterials, multiwalled carbon nanotubes (MWCNTs) are already commercialized in various products which can be in direct contact with populations. However, few studies address their potential toxicity. Although a few reports on the cytotoxicity of carbon nanotubes (CNTs) have been published, very little is known about their toxicity or genotoxicity in mammalian cells. We have for the first time compared the clastogenic/genotoxic potential of functionalized and nonfunctionalized MWCNTs in bone marrow cells of Swiss-Webster mice; using mitotic index (MI), chromosome aberrations (CA), micronuclei (MN) formation, and DNA damage in leukocytes as toxicologic endpoints. Six groups of five male mice, each weighing ∼30 ± 2 g, were administered intraperitoneally, once a day for five days with doses of 0.25, 0.5, 0.75, mg/kg body weight (BW) of functionalized and nonfunctionalized MWCNTs. Four vehicle control groups (negative) and a positive control group (carbon black) were also made of 5 mice each. Chromosome and micronuclei from bone marrow cells and comet slides from leukocytes were examined following standard protocols. The results demonstrated that MWCNTs exposure significantly increased (P < 0.05) the number of structural chromosomal aberrations, the frequency of micronucleated cells and the level of DNA damage, and decreased the mitotic index in treated groups compared to control groups. MWCNTs were shown to be toxic at sufficiently high concentrations, however purified functionalized MWCNTs had a higher clastogenic/genotoxic potential compared to nonfunctionalized form of MWCNT. The results of our study suggest that exposure to MWCNT has the potential to cause genetic damage. Hence, careful monitoring should be done with respect to designing/synthesizing biocompatible carbon nanomaterials. Further characterization of their systemic toxicity, genotoxicity and carcinogenicity is also essential.

Lack of micronuclei formation in bone marrow of rats after oral exposure to thiocyclam insecticide

In this study, a nereistoxin analogue insecticide, thiocyclam, was administered to adult male albino rats by gavage dose of 135, 270 and 540 mg/kg b.w. repeated for 5 days at 24 h intervals. Control animals received only water. Thiocyclam was tested for its potential to cause genotoxic effects in rat bone marrow cells using an in vivo micronucleus assay. After 24 h of the last treatment, rats from all dose levels were sacrificed. Bone marrow cells were collected and assayed for the presence of micronuclei. Thiocyclam did not cause any increase in the incidence of micronucleated polychromatic erythrocytes in rats bone marrow at any of the dose levels. The polychromatic erythrocytes/normochromatic erythrocytes (PCE:NCE) ratio was found to be in the range from 0.50 ± 0.11 to 0.55 ± 0.02. The results of this study demonstrate that the effect of thiocyclam is not significant in the rat in vivo micronucleus assay.

Effect of N-acetylcysteine on radiation-induced genotoxicity and cytotoxicity in rat bone marrow

The aim of this study is to evaluate the potential radioprotective effects of N-acetylcysteine (NAC) against genotoxicity and cytotoxicity. The effect of WR-2721, as a representative of clinically used radioprotector, was compared with that of NAC, using the chromosomal aberration (CA) and micronucleus (MN) test systems in the irradiated rat's femoral bone marrow cells. We also investigated the mitotic index (MI), and the ratio of polychromatic erythrocytes (PCEs) to normochromatic erythrocytes (NCEs). The rats (n = 16) were divided randomly and equally into four groups: Control (C), Radiation (R), R+NAC (received irradiation and 1000 mg/kg NAC) and R+WR-2721 (received irradiation and 200 mg/kg WR-2721) rats. All the irradiated groups received whole-body gamma irradiation as a single dose of 6 Gy. Group R showed higher CA and MN formation when compared to C. Group R showed higher frequency of MN formation when compared to both R+NAC and R+WR-2721. The mean MI and PCE/NCE ratios were lower in Group R when compared to those of Group C. The mean MI and PCE/NCE ratios of both R+NAC and R+WR-2721 groups were lower when compared to those of Group C. The MI in Group R was lower when compared to that of both R+NAC and R+WR-2721 groups. In this study, the results give clues about the beneficial effects of NAC against radiation-induced genotoxicity and cytotoxicity in rat bone marrow and its effect may be comparable to that observed for WR-2721.

Cytogenetic effects of extremely low frequency magnetic field on Wistar rat bone marrow

In this study, the genotoxic and cytotoxic potential of extremely low frequency magnetic fields (ELF-MF) was investigated in Wistar rat tibial bone marrow cells, using the chromosomal aberration (CA) and micronucleus (MN) test systems. In addition to these test systems, we also investigated the mitotic index (MI), and the ratio of polychromatic erythrocytes (PCEs) to normochromatic erythrocytes (NCEs). Wistar rats were exposed to acute (1 day for 4h) and long-term (4h/day for 45 days) to a horizontal 50Hz, 1mT uniform magnetic field generated by a Helmholtz coil system. Mitomycin C (MMC, 2mg/kg BW) was used as positive control. Results obtained by chromosome analysis do not show any statistically significant differences between the negative control and both acute and long-term ELF-MF exposed samples. When comparing the group mean CA of long-term exposure with the negative control and acute exposure, the group mean of the long-term exposed group was higher, but this was not statistically significant. However, the mean micronucleus frequency of the longer-term exposed group was considerably higher than the negative control and acutely exposed groups. This difference was statistically significant (p<0.01). The results of the MI in bone marrow showed that the averages of both A-MF and L-MF groups significantly decreased when compared to those in the negative control (p<0.001 and p<0.01, respectively). No significant differences were found between the group mean MI of A-MF exposure with L-MF. We found that the average of PCEs/NCEs ratios of A-MF exposed group was significantly lower than the negative control and L-MF exposed groups (p<0.001 and p<0.01, respectively). In addition, the group mean of the PCEs/NCEs ratios of L-MF was significantly lower than negative control (p<0.01). We also found that the MMC treated group showed higher the number of CA and the frequency of MN formation when compared to those in all other each groups (p-values of all each groups <0.01) and also MMC treated group showed lower MI and the PCEs/NCEs ratios when compared to those in all other each groups (p-values of all groups <0.01). These observations indicate the in vivo suspectibility of mammals to the genotoxicity potential of ELF-MF.

Cytogenetic effects of 1,1-dichloroethane in mice bone marrow cells

The major concern for the halogenated compounds is their widespread distribution, in addition to occupational exposures. Several chlorinated alkanes and alkenes were found to induce toxic effects. In this study, we investigated the genotoxic potential of 1,1-dichloroethane in the bone marrow cells obtained from Swiss-Webster mice, using chromosomal aberrations (CA), mitotic index (MI), and micronuclei (MN) formation as toxicological endpoints. Five groups of three male mice each, weighing an average of 24 +/- 2 g, were injected intraperitoneally, once with doses of 100, 200, 300, 400, 500 mg/kg body weight (BW) of 1,1-dichloroethane dissolved in ethanol. A control group was also made of three animals injected with ethanol (1%) without the chemical. All animals were sacrificed 24 hours after the treatment. Chromosome and micronuclei preparations were obtained from bone marrow cells following standard protocols. Chromatid and chromosome aberrations were investigated in 100 metaphase cells per animal and percent micronuclei frequencies were investigated in 1,000 metaphase cells per animal. 1,1-dichloroethane exposures significantly increased the number of chromosomal aberrations and the frequency of micronucleated cells in the bone marrow cells of Swiss-Webster mice. Percent chromosomal aberrations of 2.67 +/- 0.577, 7.66 +/- 2.89, 8.33 +/- 2.08, 14.67 +/- 2.51, 20.3 +/- 3.21, 28 +/- 3.61; mitotic index of 9.4%, 7.9%, 6.2%, 4.3%, 3.0%, 2.6% and micronuclei frequencies of 3.33 +/- 0.7, 7.33 +/- 0.9, 8.00 +/- 1.0, 11.67 +/- 1.2, 15.33 +/- 0.7, 18.00 +/- 1.7 were recorded for the control, 100, 200, 300, 400, and 500 mg/kg BW respectively; indicating a gradual increase in number of chromosomal aberrations and micronuclei formation, with increasing dose of 1,1,-dichloroethane. Our results indicate that 1,1-dichloroethane has a genotoxic potential as measured by the bone marrow CA and MN tests in Swiss-Webster mice.

In vivo cytogenetic effects of a commercially formulated mixture of cypermethrin and quinalphos in mice

In vivo cytogenetic effects of commercially formulated cypermethrin (CYP, synthetic pyrethroid insecticide) and/or quinalphos (QUI, organophosphate insecticide), generally used in combination, were examined through chromosomal aberrations (CA) and micronucleus test (MT) in mice. Male mice were orally gavaged to a single dose of CYP/QUI commercial mixture (22, 44 or 67 mg/kg b.wt.) for 24h (CA) or 48 h (MT). Based on the concentrations of active ingredients of CYP and QUI present in the test doses of CYP/QUI mixture, mice were orally exposed to 0.66, 1.32 and 2 mg/kg of CYP or 4.4, 8.8 and 13.4 mg/kg of QUI. For reference, a group of five mice was intraperitoneally administered to cyclophosphamide (20 or 50 mg/kg) or orally gavaged to peanut oil for vehicle control. Exposure of CYP/QUI mixture inhibited the mitotic index (MI) and induced CA in a dose-dependent manner at 24 h; however, significant (p<0.01 or 0.001) frequencies of CA were observed at 44 mg/kg onwards, whereas inhibition of MI at 67 mg/kg. Independent exposure of QUI at 8.8 mg/kg onwards also significantly (p<0.01 or 0.001) inhibited MI and induced CA, whereas CYP at 2 mg/kg (highest concentration in CYP/QUI mixture) inhibited MI significantly but failed to induce CA. Chromatid breaks and fragments found to be frequent aberrations in all the test groups. Treatment of CYP/QUI mixture also induced micronucleus formation dose-dependently at 48 h, yet statistically significant (p<0.001) frequencies of micronucleated polychromatic erythrocytes (MNPCE) were observed at 44 mg/kg onwards. QUI (8.8 and 13.4 mg/kg) alone also induced significant frequencies of MNPCE, whereas frequencies of MNPCE observed with the CYP even at 2 mg/kg were comparable to that of vehicle control. Present findings indicate the genotoxicity potential of CYP/QUI mixture and suggest that the simultaneous presence of the toxic doses of CYP and QUI can lead to synergistic genotoxicity in mice and may pose mutagenic risk in human beings.

Municipal sludge leachate-induced genotoxicity in mice—a subacute study

Inappropriate disposal of municipal sludge (MS) results in the leaching of toxic metals and organic chemicals, which can contaminate the surface and ground water leading to the serious health hazards. In this study, the genotoxic potential of the leachate prepared from MS sample was examined in mouse bone marrow cells through chromosomal aberrations (CA), micronucleus test (MT) and comet assay. Analysis of metals and physicochemical parameters of the leachate was also carried out to correlate the genotoxic results. The dried sludge showed high concentrations of heavy metals, viz. Cr, Cu, Pb and Ni. However, in 10% leachate, concentrations of these metals were manifold lower than that of obtained in dried sludge. Male mice orally gavaged to leachates (0.1-0.4 ml/mouse/day) for 15 days revealed significant (P<0.01, P<0.001) inhibition of mitotic index (MI) and induction of chromatid/chromosome fragments and breaks in all the treatment groups. The effect was observed to be dose-dependent. Treatment of mice with leachates also induced significant (P<0.001) frequencies of micronucleated polychromatic erythrocytes (MNPCE). The results of comet assay revealed a statistically significant (P<0.05 and <0.01) DNA damage in bone marrow cells exposed to 0.2-0.4 ml/mouse/day. Findings of the present study indicate that the constant exposure of MS leachate can cause genotoxic effects in mammals and suggest risks in human population.

Cytogenetic evaluation of arsenic trioxide toxicity in Sprague-Dawley rats

Acute exposure to arsenic trioxide has been reported to induce death and/or multiple organ damage with symptoms including nausea, vomiting, diarrhea, gastrointestinal hemorrhage, cerebral edema, tachycardia, dysrhythmias and hypovolemic shock. Its toxic effects are due to its ability to bind to sulfhydryl groups of proteins and to inhibit energy production. Although the chronic exposure to arsenic trioxide has been linked to various types of cancer, such as skin, liver, lung, bladder and kidney neoplasms, studies of its carcinogenic potential in animals have not been conclusive. In this study, we investigated the genotoxic potential of arsenic trioxide in bone-marrow cells obtained from Sprague-Dawley rats; using chromosomal aberrations (CA), mitotic index (MI) and micronuclei (MN) formation as the toxicological endpoints. Four groups of six male rats each, weighing approximately 60+/-2 g per rat, were injected intraperitoneally, once a day for 5 days with doses of 5, 10, 15 and 20 mg/kg body weight (BW) of arsenic trioxide dissolved in distilled water. A control group was also made of six animals injected with distilled water without chemical. All the animals were sacrificed at the end of the treatment period. Chromosome and micronuclei preparation was obtained from bone-marrow cells following standard protocols. Arsenic trioxide exposure significantly increased the number of structural chromosomal aberrations, the frequency of micronucleated cells and decreased the mitotic index in treated groups when compared with the control group. Our results demonstrate that arsenic trioxide has a clastogenic/genotoxic potential as measured by the bone-marrow CA and MN tests in Sprague-Dawley rats.

Evaluation of cytogenetic effects of lambda-cyhalothrin on Wistar rat bone marrow by gavage administration

In this study, a synthetic pyrethroid insecticide, lambda-cyhalothrin (LCT), was administered to adult female albino rats (Wistar rats) by gavage dose of 6.12, 3.06, 0.8 mg/kg b.w. repeated for 13 days at 48 h intervals. The cytotoxic and genotoxic effects of LCT were investigated in bone marrow cells, using the structural chromosomal aberration (SCA) and micronucleus (MN) test systems. Mitomycin C (MMC) was also used as positive control (2mg/kg b.w.). All the doses of LCT increased the number of SCAs and the frequency of micronucleated erythrocytes, with respect to the control group. Only the highest dose of LCT significantly increased the MN frequency compared with control (P < 0.01). It was also observed that LCT caused a significant decrease in the number of polychromatic erythrocytes compared with controls (p < 0.001). These observations indicate the in vivo suspectibility of mammals to the genetic toxicity and cytotoxicity potential of LCT.

Induction of micronuclei by lambda-cyhalothrin in Wistar rat bone marrow and gut epithelial cells

We have investigated the genotoxicity of lambda-cyhalothrin (LCT) (CAS registry No. 91465-08-06), a pyrethroid insecticide, in bone marrow cells and in colonic crypt epithelial cells of groups of four rats per dose treated in vivo by gavage at doses of 0.8, 3.06 and 6.12 mg/kg body weight (body wt). We measured genotoxicity using the micronucleus (MN) assay, scoring 2000 polychromatic erythrocytes (PCEs) per animal for bone marrow and 1000 colonic crypt epithelial cells per animal for the colon. We assessed cytotoxicity in bone marrow by calculating the ratio of PCEs to normochromatic erythrocytes, and in the colonic crypt epithelium by observing the frequency of binucleate cells and the mitotic index in 1000 cells. Apoptosis in colonic crypt epithelial cells was measured by observing the frequency of karyorrhexis and karyolysis in 1000 cells. We found that LCT induced a statistically significant dose-related increase in MN formation in the bone marrow and the colonic crypt. The colonic epithelium was more sensitive to the clastogenic effects of LCT than the bone marrow as judged by the significantly higher frequencies of MN in the colon than in the bone marrow at doses of 3.06 and 6.12 mg/kg body wt.

Induction of chromosome aberrations, micronucleus formation and sperm abnormalities in mouse following carbofuran exposure

Carbofuran was tested to study in vivo cytogenetic effects in mouse bone marrow cells and morphological alterations in sperms. The acute oral and intraperitoneal (i.p.) LD(50) of carbofuran was determined to be 9.5 or 2.0 mg/kg b.w. in mice, respectively. The animals were orally administered 1.9, 3.8 or 5.7 mg/kg b.w. (20, 40 and 60% of LD(50)) of carbofuran for 24 h or 1.9 mg/kg b.w. for 4 consecutive days (cumulative 7.6 mg/kg or 80% of LD(50)) to analyse chromosome aberrations (CAs). For micronucleus test (MT) animals were orally exposed to 5.7 mg/kg b.w. for 24 and 48 h or 1.9 mg/kg b.w. for 4 consecutive days. For reference mice were exposed to peanut oil (negative control) and cyclophosphamide (20 mg/kg) or ethyl methanesulfonate (EMS: 100 mg/kg) positive control for CAs and MT respectively. To analyse the effect on sperm morphology mice were exposed to single i.p. dose of 1 and 2 mg/kg b.w. of carbofuran and repeatedly to 0.5 mg/kg for 5 consecutive days. Cytogenetic analysis revealed that all the test doses induced mitotic inhibition, CAs, micronucleus (MN) formation and sperm abnormalities in a dose dependent manner. Present observations concurrent with earlier reports substantiate the genotoxic potential of carbofuran and possible risk to human beings.

Cytogenetic effects of deltamethrin on rat bone marrow

Deltamethrin, a synthetic pyrethroid insecticide, was administered to adult female albino rats as a single i.p., s.c., or oral dose of 5.6, 8.4, or 11.2 mg/kg b.w. or repeated i.p. doses of 2.24 mg/kg b.w. for five consecutive days (cumulative dose 11.2 mg/kg b.w.). This treatment inhibited the mitotic index in a dose-dependent manner and increased the frequency of chromosome aberrations in the bone marrow at 24 h post exposure. The parenterally (i.p. and s.c.) administered deltamethrin appeared more effective than the oral gavage for eliciting its cytotoxicity and genetic toxicity potential. The frequency of micronucleated erythrocytes in the bone marrow was also increased at 30 h following a single i.p. dose of 5.6, 8.4, or 11.2 mg/kg b.w. The most prevalent abnormality observed in this study was endomitotic reduplication of chromosomes which, along with mitotic inhibition and micronucleus induction, indicated microtubular/mitotic spindle poisoning by deltamethrin. The increased frequency of chromosome aberrations and micronucleated erythrocytes also suggests a clastogenic potential of deltamethrin. These observations indicate the in vivo susceptibility of mammals to the genetic toxicity potential of deltamethrin.