Protection against genotoxic damages following whole body gamma radiation exposure in mice by lipoic acid

Alpha-lipoic acid (LA) protected plasmid pBR 322 DNA, under in vitro conditions from gamma radiation induced strand breaks as evidenced by the prevention of the loss of supercoiled covalently closed circular form upon irradiation. It also protected the membrane lipids of liver homogenates from the oxidative damages. Whole body exposure of mice to gamma-radiation resulted in damage to cellular DNA in various tissues and administration of LA prior to the radiation exposure prevented the radiation induced DNA damage as assessed by alkaline comet assay. Administration of LA to mice prior to the radiation exposure also prevented induction of chromosomal damages in bone marrow cells and formation of micronuclei in blood reticulocytes. Thus taken together, LA a normal cellular constituent could be used as a radioprotector against whole body radiation exposure scenarios.     

Baicalein protects mice against radiation-induced DNA damages and genotoxicity

Baicalein is the major flavonoid extracted from the root of Scutellaria baicaleins. This flavonoid is used extensively in Chinese herbal medicine. In the present study baicalein is evaluated for its radioprotective properties. Human blood cells when exposed to the γ-radiation ex vivo in presence of baicalein underwent the reduced DNA damage compared to the control. Baicalein administration prior to the whole-body γ-radiation (4 Gy) exposure of mice resulted in protecting the damage to the DNA as measured in their blood cells by alkaline comet assay. Mice when exposed to the radiation (whole body; 1.7 Gy) resulted in damage to the bone marrow as measured by micronucleated reticulocyte (MNRET) formation. Baicalein pre-treatment reduces the radiation induced damage to the bone marrow cells, as there was decrease in the percentage MNRET formation. These findings indicate radio-protecting ability of baicalein.     

Evaluation of the mutagenic potential of the antichagasic drug Rochagan in healthy and chagasic rodents

Benznidazole (bz) is the active component of the antichagasic drug Rochagan. Tests were carried out to detect the induction of chromosomal aberrations and micronuclei in rodent bone marrow cells and peripheral blood cells, respectively. Rats were exposed to acute treatment with Rochagan by gavage at total doses of 150, 300, 1500, 2000 and 3000 mg bz/kg body weight and killed at different times. In the chronic treatments, healthy and chagasic Balb/c mice were treated with Rochagan by gavage at a dose of 100 mg bz/kg/day for 10 and 25 days. No significant increase in frequency of chromosomal aberrations in bone marrow cells or of micronuclei in peripheral blood cells was detected in the animals acutely or chronically exposed to Rochagan in vivo.     

Clastogenicity of carbazole in mouse bone marrow cells in vivo

Clastogenicity of carbazole was evaluated by employing mouse in vivo chromosomal aberration (CA) test. Carbazole administered intraperitoneally (i.p.) at the rate of 25, 50, 100, 150 and 200 mg/kg b.w. to Swiss albino mice in vivo resulted in mitotic depression and induction of chromosomal aberrations. Dose related decrease in mitotic index (MI) and increase in the frequencies of chromosomal aberrations per cell (CAs/cell) and percent abnormal cells were recorded in bone marrow cells. However, statistically significant reduction in MI and increase in CAs/cell and percent abnormal cells were found only for the two higher doses. The results obtained indicate that carbazole or its metabolite, if any, is moderately clastogenic in the bone marrow cells of Swiss albino mice.     

Radiation protection of DNA by ferulic acid under in vitro and in vivo conditions

The effect of ferulic acid was studied on γ-radiation-induced relaxation of plasmid pBR322 DNA and induction of DNA strand breaks in peripheral blood leukocytes and bone marrow cells of mice exposed to whole body γ-radiation. Presence of 0.5 mM ferulic acid significantly inhibited the disappearance of supercoiled (ccc) plasmid pBR322 with a dose modifying factor (DMF) of 2.0. Intraperitoneal administration of different amounts (50, 75 and 100 mg/kg body weight) of ferulic acid 1 h prior to 4 Gy γ-radiation exposure showed dose-dependent decrease in the yield of DNA strands breaks in murine peripheral blood leukocytes and bone marrow cells as evidenced from comet assay. The dose-dependent protection was more pronounced in bone marrow cells than in the blood leukocytes. It was observed that there was a time-dependent disappearance of radiation induced strand breaks in blood leukocytes (as evidenced from comet parameters) following whole body radiation exposure commensuration with DNA repair. Administration of 50 mg/kg body weight of ferulic acid after whole body irradiation of mice resulted disappearance of DNA strand breaks at a faster rate compared to irradiated controls, suggesting enhanced DNA repair in ferulic acid treated animals. (Mol Cell Biochem xxx: 209–217, 2005)     

mFISH analysis of chromosomal damage in bone marrow cells collected from CBA/CaJ mice following whole body exposure to heavy ions (<Superscript>56</Superscript>Fe ions)

To date, there is scant information on in vivo induction of chromosomal damage by heavy ions found in space (i.e. ⁵⁶Fe ions). For radiation-induced response to be useful for risk assessment, it must be established in in vivo systems especially in cells that are known to be at risk for health problems associated with radiation exposure (such as hematopoietic cells, the known target tissue for radiation-induced leukemia). In this study, the whole genome multicolor fluorescence in situ hybridization (mFISH) technique was used to examine the in vivo induction of chromosomal damage in hematopoietic tissues, i.e. bone marrow cells. These cells were collected from CBA/CaJ mice at day 7 following whole-body exposure to different doses of 1 GeV/amu ⁵⁶Fe ions (0, 0.1, 0.5 and 1.0 Gy) or ¹³⁷Cs γ rays as the reference radiation (0, 0.5, 1.0 and 3.0 Gy, at the dose rate of 0.72 Gy/min using a GammaCell40). These radiation doses were the average total-body doses. For each radiation type, there were four mice per dose. Several types of aberrations in bone marrow cells collected from mice exposed to either type of radiation were found. These were exchanges and breaks (both chromatid- and chromosome-types). Chromosomal exchanges included translocations (Robertsonian or centric fusion, reciprocal and incomplete types), and dicentrics. No evidence of a non-random involvement of specific chromosomes in any type of aberrations observed in mice exposed to ⁵⁶Fe ions or ¹³⁷Cs γ rays was found. At the radiation dose range used in our in vivo study, the majority of exchanges were simple. Complex exchanges were detected in bone marrow cells collected from mice exposed to 1 Gy of ⁵⁶Fe ions or 3 Gy of ¹³⁷Cs γ rays only, but their frequencies were low. Overall, our in vivo data indicate that the frequency of complex chromosome exchanges was not significantly different between bone marrow cells collected from mice exposed to ⁵⁶Fe ions or ¹³⁷Cs γ rays. Each type of radiation induced significant dose-dependent increases (ANOVA, P < 0.01) in the frequencies of chromosomal damage, including the numbers of abnormal cells. Based upon the linear-terms of dose-response curves, ⁵⁶Fe ions were 1.6 (all types of exchanges), 4.3 (abnormal cells) and 4.2 (breaks, both chromatid- and chromosome-types) times more effective than ¹³⁷Cs γ rays in inducing chromosomal damage.     

Mentha piperita (Linn.) leaf extract provides protection against radiation induced chromosomal damage in bone marrow of mice

Oral administration of M. piperita (1 g/kg body weight/day) before exposure to gamma radiation was found to be effective in protecting against the chromosomal damage in bone marrow of Swiss albino mice. Animals exposed to 8 Gy gamma radiation showed chromosomal aberrations in the form of chromatid breaks, chromosome breaks, centric rings, dicentrics, exchanges and acentric fragments. There was a significant increase in the frequency of aberrant cells at 6 hr after irradiation. Maximum aberrant cells were observed at 12 hr post-irradiation autopsy time. Further, the frequency of aberrant cells showed decline at late post-irradiation autopsy time. However, in the animals pretreated with Mentha extract, there was a significant decrease in the frequency of aberrant cells as compared to the irradiated control. Also significant increase in percentage of chromatid breaks, chromosome breaks, centric rings, dicentrics, exchanges, acentric fragments, total aberrations and aberrations/damaged cell was observed at 12 hr post-irradiation autopsy time in control animals, whereas Mentha pretreated irradiated animals showed a significant decrease in percentage of such aberrations. A significant decrease in GSH content and increase in LPO level was observed in control animals, whereas Mentha pretreated irradiated animals exhibited a significant increase in GSH content and decrease in LPO level but the values remained below the normal. The radioprotective effect of Mentha was also demonstrated by determining the LD(50/30) values (DRF = 1.78). The results from the present study suggest that Mentha pretreatment provides protection against radiation induced chromosomal damage in bone marrow of Swiss albino mice.     

Comparison of the level of sister chromatid exchanges and chromosome aberrations induced by chemical mutagens in vitro and in vivo

The paper presents results of a study of a dose dependence of induction of SCE and chromosomal aberrations at the exposure of human lymphocytes in vitro and bone marrow cells of mice in vivo to 5 alkylating chemicals. The efficiency of SCE induction in vitro is found to be 300-30 times as high as that of arising of chromosomal aberrations. The same regularity is observed in experiments in vivo, but the ratio is reduced to 60-20 times.     

Correlation of the sister chromatid exchange level with chromosome aberrations induced by chemical mutagens in vivo

The data on the dose dependencies of the induction of sister chromatid exchanges (SCE) and chromosomal aberrations during exposure of mouse bone marrow cells in vivo to 5 alkylating substances are provided. The efficacy of SCE induction was found to be higher than that of chromosomal aberrations. It was established that SCE induced by chemical mutagens in vivo and in vitro are more sensitive and stable tests than chromosomal aberrations.     

A comparative study on the genotoxic effect of pyrimethamine in bone marrow and spermatogonial mice cells

Pyrimethamine is an antimalarial agent widely used in clinical therapy. We aimed to compare its mutagenic potential in mammalian spermatogonial and bone marrow cells. For studying chromosomal aberrations mice were treated acutely (single treatment) with 4 dose levels of pyrimethamine (5, 10, 20 and 40 mg/kg). Pyrimethamine was found to produce a significant increase in structural chromosomal aberrations after acute treatment in bone marrow cells of mice (p < 0.001). It also induced chromosome abnormalities in spermatogonial cells (p < 0.05) at the highest dose.     

Lack of detectable transmissible chromosomal instability after in vivo or in vitro exposure of mouse bone marrow cells to 224Ra alpha particles

Several studies over recent years have highlighted the possibility that radiation can induce transmissible genomic instability. Most of these involve in vitro irradiation and usually in vitro culture. Here it is reported that the short-half-life bone-seeking alpha-particle emitter (224)Ra did not induce excess transmissible chromosomal instability in CBA/H mouse bone marrow cells in a 100-day period after in vivo or in vitro exposure. Similarly, no excess transmissible chromosomal instability could be detected after in vivo whole-body X irradiation. It was noted, however, that short-term culture of murine bone marrow cells elevated yields of aberrations, as did transplantation of untreated marrow into radiation-ablated hosts. These findings emphasize the sensitivity of murine hemopoietic tissue to experimental manipulation and reinforce the importance of appropriate concurrent control experiments in any investigation of transmissible genomic instability.     

Cytotoxic effects of antimony trichloride on mice in vivo.

Clastogenic effects of antimony trichloride, used in small industries, were monitored in laboratory bred white Swiss mice in vivo, following oral administration by gavaging, after 6, 12, 18 and 24 h. Chromosomal aberrations were principally breaks and damaged cells observed from bone marrow preparations. The frequencies of chromosomal aberrations were directly related to the dose used and were significantly higher than the control. The chemical did not alter the frequency of dividing cells to any significant level.     

Chromosomal damage induced by maleic hydrazide in mammalian cells in vitro and in vivo

The induction of sister-chromatid exchanges (SCE) and chromosomal aberrations (Ch.Ab.) by the herbicide maleic hydrazide (MH) has been investigated in Chinese hamster ovary (CHO) cells grown in vitro and in bone marrow cells of mice treated in vivo. MH induces SCE and Ch.Ab. in CHO cells without metabolic activation; however, no induction of SCE was found in the in vivo experiments.     

Chromosomal aberrations in the bone marrow cells of mice induced by accelerated (12)C(6+) ions

The whole bodies of 6-week-old male Kun-Ming mice were exposed to different doses of (12)C(6+) ions or X-rays. Chromosomal aberrations of the bone marrow (gaps, terminal deletions and breaks, fragments, inter-chromosomal fusions and sister-chromatid union) were scored in metaphase 9h after exposure, corresponding to cells exposed in the G(2)-phase of the first mitosis cycle. Dose-response relationships for the frequency of chromosomal aberrations were plotted both by linear and linear-quadratic equations. The data showed that there was a dose-related increase in the frequency of chromosomal aberrations in all treated groups compared to controls. Linear-quadratic equations were a good fit for both radiation types. The compound theory of dual radiation action was applied to decipher the bigger curvature (D(2)) of the dose-response curves of X-rays compared to those of (12)C(6+) ions. Different distributions of the five types of aberrations and different degrees of homogeneity were found between (12)C(6+) ion and X-ray irradiation and the possible underlying mechanism for these phenomena were analyzed according to the differences in the spatial energy deposition of both types of radiation.     

The in vivo effects of interleukin 1. I. Bone marrow cells are induced to cycle after administration of interleukin 1

We have previously reported that interleukin 1 (IL-1) administration 20 hr before irradiation protects mice from lethal effects of radiation. The recovery of total nucleated bone marrow cells and of hematopoietic progenitor cells was enhanced in IL-1 treated, as compared to untreated, irradiated mice. This suggested that IL-1 administration may affect the cells in the bone marrow of normal mice. Intraperitoneal administration of recombinant IL-1 resulted in bone marrow cell enlargement and increased cycling of these enlarged cells. In addition, the capacity of bone marrow cells from IL-1 treated mice to proliferate in response to granulocyte macrophage-colony-stimulating factor (GM-CSF) in cell suspension cultures was enhanced. The above effects were not genetically restricted as C57BL/6, B6D2F1, C3H/HeN, and C3H/HeJ mice showed similar responses. A comparative study showed that 100 ng of IL-1 was much more effective in stimulating bone marrow cells by the above criteria than 5 micrograms GM-CSF. Since IL-1, unlike CSF, can not be demonstrated to have a direct in vitro stimulatory effect on bone marrow cells, the aforementioned in vivo effects of IL-1 are presumably mediated by other hematopoietic growth factors. We have previously shown that IL-1 induces the appearance of high titers of CSF in the serum. Consequently hematopoietic growth factors that are generated at local sites following IL-1 administration may mediate the observed cell cycling effect.     

Radioprotective effect of rhizome extract of Zingiber montanum in Rattus norvegicus

The present study aims at determining the ability of 60% ethanol extract of the rhizome of Zingiber montanum (J. K?nig) A. Dietr. to protect bone marrow cells in vivo from radiation-induced chromosomal aberrations. Albino rats (Rattus norvegicus, 2n = 42) were used to carry out investigations on the radioprotective properties of Z. montanum. Acute toxicity of the extract was determined, and a suitable injectable dose was selected for intra-peritoneal administration. The LD(50) of the extract calculated for 72 h was 2.9 g/kg, and the calculated LD(10) dose was 1.7 g/kg. The calculated maximum tolerated dose of the rhizome extract was 1.3 g/kg. Rats were divided into 12 groups (with or without the administration of extract) and exposed to different radiation doses from 1 to 5 Gy. Whole-body irradiation of rats showed a significant dose-dependent increase in different types of chromosomal aberrations. The most common chromosomal aberrations were breaks, fragments, gaps, rings, endoreduplications and dicentric chromosomes. Ethanol extract of rhizome at a dose of 0.5 g/kg did not show any significant increase in chromosomal aberrations in unirradiated animals as compared to that of the control group. Intra-peritoneal administration of the extract at a dose of 0.5 g/kg considerably reduced the frequency of the aberrations stated above in irradiated animals with DMF value of 1.36 at 1 to 5 Gy dose range of gamma radiation. The incidence of micronucleated polychromatic erythrocytes and micronucleated normochromatic erythrocytes due to the radiation exposure was considerably reduced in extract-treated groups of animals with DMFs 1.34 and 1.17, respectively, as compared to that of the extract-untreated groups. Our results suggest that rhizome extract of Z. montanum may have a potential in protecting normal hematopoietic cells from radiation-induced damage.     

In vivo cytogenetic effects of cooked food mutagens

Using a variety of in vivo cytogenetic endpoints, we have investigated the effects of several compounds formed during the cooking of meat. C57Bl/6 mice were used to test for an increase in the frequency of sister-chromatid exchanges (SCEs), chromosomal aberrations, and micronucleated erythrocytes by 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). MeIQx and DiMeIQx did not induce SCEs in mouse bone marrow cells. PhIP induced sister-chromatid exchanges, but not chromosomal aberrations in bone marrow. In peripheral blood lymphocytes, PhIP did induce aberrations at 100 mg/kg, the highest dose tested. PhIP induced a low but significantly increased frequency of micronuclei in normochromatic but not polychromatic erythrocytes in bone marrow and peripheral blood. However, dose responses were not observed. With the exception of the SCEs induced by PhIP, these results contrast with observations made in vitro, where these compounds were found to have significant genotoxicity in mammalian cells and a very high mutation frequency in prokaryotic systems.     

Sister chromatid exchange and chromosome aberrations induced by curcumin and tartrazine on mammalian cells in vivo

Sister chromatid exchanges (SCEs) and chromosomal aberrations induced by curcumin (a natural dye) and tartrazine (a synthetic dye) were studied on bone marrow cells of mice and rats following acute and chronic exposure via the diet. Except for two low concentrations in the curcumin and one low concentration in the tartrazine treated series a significant increase in SCEs was observed in all the concentrations of the two dyes tested. Except for two high concentrations during the 9 months treatment no significant increase in chromosomal aberrations was observed in the curcumin treated series, whereas tartrazine showed a significant increase in chromosomal aberrations in some of the higher concentrations in all the series tested. The results indicate that tartrazine is more clastogenic than curcumin.     

Radioprotective effects of Dragon's blood and its extract against gamma irradiation in mouse bone marrow cells

PurposeThe radioprotective effects of Dragon's blood (DB) and its extracts (DBE) were investigated using the chromosomal aberrant test, micronucleus and oxidative stress assay for anti-clastogenic and anti-oxidative activity.Materials and methodsAdult BALB/C mice were exposed to the whole body irradiation with 4 Gy ⁶⁰Co γ-rays. DB and DBE were administered orally once a day from 5 days prior to irradiation treatment to 1 day after irradiation. The mice were sacrificed on 24 h after irradiation. The cells of bone marrow were measured by counting different types of chromosomal aberrations and the frequency of micronuclei. Oxidative stress response was carried out by analysis of serum from blood.ResultsDB and DBE significantly decreased the number of bone marrow cells with chromosome aberrations after irradiation with respect to irradiated alone group. The administration of DB and DBE also significantly reduced the frequencies of micronucleated polychromatic erythrocytes (MPCE) and micronucleated normochromatic erythrocytes (MNCE). In addition, DB and DBE markedly increased the activity of antioxidant enzymes and the level of antioxidant molecular. Malondialdehyde (MDA) and nitric oxide (NO) levels in serum were significantly reduced by DB and DBE treatment.ConclusionsOur data suggested that DB and DBE have potential radioprotective properties in mouse bone marrow after ⁶⁰Co γ-ray exposure, which support their candidature as a potential radioprotective agent.     

Treatment of mice with a herbal preparation (Liv. 52) reduces the frequency of radiation-induced chromosome damage in bone marrow

Induction of chromosomal aberrations was studied from 1/4 to 14 days post irradiation in the bone marrow of mice treated or not with Liv. 52, a herbal preparation, prior to 4.5 Gy exposure. The frequency of chromatid and chromosomal aberrations started increasing at day 1/4 in the irradiation and Liv. 52 + irradiated groups. The highest frequency of aberrations was recorded at day 1/2 post exposure which declined after day 1 in both groups. The frequency of both types of aberrations was significantly lower in the Liv. 52 + irradiated group than in the irradiated group.