Maternal and fetal chromosomal aberrations in mice following prenatal exposure to subembryotoxic doses of lead nitrate

Sidestream Smoke Extracts from Harm-Reduction and Conventional Camel Cigarettes Inhibit Osteogenic Differentiation via Oxidative Stress and Differential Activation of intrinsic Apoptotic Pathways

Epidemiological studies suggest cigarette smoking as a probable environmental factor for a variety of congenital anomalies, including low bone mass, increased fracture risk and poor skeletal health. Human and animal in vitro models have confirmed hypomineralization of differentiating cell lines with sidestream smoke being more harmful to developing cells than mainstream smoke. Furthermore, first reports are emerging to suggest a differential impact of conventional versus harm-reduction tobacco products on bone tissue as it develops in the embryo or in vitro. To gather first insight into the molecular mechanism of such differences, we assessed the effect of sidestream smoke solutions from Camel (conventional) and Camel Blue (harm-reduction) cigarettes using a human embryonic stem cell osteogenic differentiation model. Sidestream smoke from the conventional Camel cigarettes concentration-dependently inhibited in vitro calcification triggered by high levels of mitochondrially generated oxidative stress, loss of mitochondrial membrane potential, and reduced ATP production. Camel sidestream smoke also induced DNA damage and caspase 9-dependent apoptosis. Camel Blue-exposed cells, in contrast, invoked only intermediate levels of reactive oxygen species insufficient to activate caspase 3/7. Despite the absence of apoptotic gene activation, damage to the mitochondrial phenotype was still noted concomitant with activation of an anti-inflammatory gene signature and inhibited mineralization. Collectively, the presented findings in differentiating pluripotent stem cells imply that embryos may exhibit low bone mineral density if exposed to environmental smoke during development.

Modified natural clinoptilolite detoxifies small mammal's organism loaded with lead II: genetic, cell, and physiological effects

The detoxification capacity of the clinoptilolite modification KLS-10-MA used as food additive in small mammals, chronically lead-exposed, was proven for the first time. The modified clinoptilolite was prepared based on natural Bulgarian clinoptilolite deposits. As a powder, it was mechanically mixed at 12.5% concentration with the conventional forage for small rodents. Lead in the form of aqueous solution of Pb(NO(3))(2) was diluted in the drinking water. In the ecotoxicological experiment covering 90 days, imprinting control region laboratory mice were used. They were allocated into four groups: group 1, (control): animals fed with conventional food for small rodents and water; group 2: animals fed with conventional food + clinosorbent KLS-10-MA and water; group 3: animals fed with conventional food and water + Pb(NO(3))(2); and group 4: animals fed with conventional food + KLS-10-MA and water + Pb(NO(3))(2). A group of non-exposed healthy animals was fed with conventional forage mixed with KLS-10-MA to prove eventual toxicity of the sorbent and influence on growth performance. The changes in the chromosome structure, mitotic index, erythrocyte form, erythropoiesis, and body weight gain were recorded. On day 90, the following relations were established: Pb-exposed and clinoptilolite-supplemented mice exhibited 2.3-fold lower chromosome aberrations frequency, 2.5-fold higher mitotic index, and 1.5-fold higher percentage normal erythrocytes 1.3-fold higher body weight compared to Pb-exposed and unsupplemented animals. The obtained data showed that the sorbent is practically non-toxic. The results of the present study encourage a further elaboration of a reliable drug based on the tested substance in the cases of chronic lead intoxication.

A core in vitro genotoxicity battery comprising the Ames test plus the in vitro micronucleus test is sufficient to detect rodent carcinogens and in vivo genotoxins

In vitro genotoxicity testing needs to include tests in both bacterial and mammalian cells, and be able to detect gene mutations, chromosomal damage and aneuploidy. This may be achieved by a combination of the Ames test (detects gene mutations) and the in vitro micronucleus test (MNvit), since the latter detects both chromosomal aberrations and aneuploidy. In this paper we therefore present an analysis of an existing database of rodent carcinogens and a new database of in vivo genotoxins in terms of the in vitro genotoxicity tests needed to detect their in vivo activity. Published in vitro data from at least one test system (most were from the Ames test) were available for 557 carcinogens and 405 in vivo genotoxins. Because there are fewer publications on the MNvit than for other mammalian cell tests, and because the concordance between the MNvit and the in vitro chromosomal aberration (CAvit) test is so high for clastogenic activity, positive results in the CAvit test were taken as indicative of a positive result in the MNvit where there were no, or only inadequate data for the latter. Also, because Hprt and Tk loci both detect gene-mutation activity, a positive Hprt test was taken as indicative of a mouse-lymphoma Tk assay (MLA)-positive, where there were no data for the latter. Almost all of the 962 rodent carcinogens and in vivo genotoxins were detected by an in vitro battery comprising Ames+MNvit. An additional 11 carcinogens and six in vivo genotoxins would apparently be detected by the MLA, but many of these had not been tested in the MNvit or CAvit tests. Only four chemicals emerge as potentially being more readily detected in MLA than in Ames+MNvit--benzyl acetate, toluene, morphine and thiabendazole--and none of these are convincing cases to argue for the inclusion of the MLA in addition to Ames+MNvit. Thus, there is no convincing evidence that any genotoxic rodent carcinogens or in vivo genotoxins would remain undetected in an in vitro test battery consisting of Ames+MNvit.

Bioaccumulation and damaging action of polymetal industrial dust on laboratory mice Mus musculus alba .II. Genetic, cell, and metabolic disturbances

An ecologo-toxicological experiment was carried out with laboratory mice Mus musculus alba of the inbred line BALB/c. The experimental animals (male and female) were exposed for 120 days to polymetal industrial dust containing zinc, copper, lead, and cadmium, which was mixed with conventional animal food. Chromosome aberration frequency and pathological changes in hematological indices, oxygen consumption, body temperature, and body weight were studied in the context of heavy metal bioaccumulation and interactions. Samples for analyses were taken on days 15, 40, 60, and 90. An increased frequency of chromosome aberrations (up to 22%), lead-induced anemia, and significant decreases in body temperature were observed. A strong correlation between hemoglobin content and oxygen consumption (O2/g h) was established. An increase in hematocrit, accompanied by a loss of body weight after day 60, suggests dehydration resulting from lead and cadmium poisoning.

A comparative analysis of the heavy metal loading of small mammals in different regions of Bulgaria II: chromosomal aberrations and blood pathology

Heavy metal content was monitored in small mammals inhabiting mountain ecosystems and two industrial polluted regions in Bulgaria. Rodents (Microtus arvalis, M. rossiaemeridionalis, Clethrionomys glareolus, Pitymys subterraneus, Chionomys nivalis, Apodemus flavicollis, A. sylvaticus, and Mus macedonicus) were used as zoomonitors. Pathological changes in chromosome status, hematological indices, and blood cell morphology were analyzed in the context of heavy metal bioaccumulation. Significant correlations were obtained between the heavy metal load of zoomonitors and the frequency of chromosomal aberrations and pathological changes in erythrocytes (mainly micronuclei and basophilic granulations). It is suggested that mercury is a strong damaging factor for chromosomes and red blood cell apparatus.

Genotoxic effect of lead nitrate on mice using SCGE (comet assay)

Single stranded DNA breakage induced by lead nitrate in mice has been studied in vivo using alkaline single cell gel electrophoresis (comet assay). Mice were administered orally 0.7, 1.4, 2.8, 5.6, 11. 2, 22.4, 44.8 and 89.6 mg/kg body weight of lead nitrate and the assay was performed on whole blood at 24, 48, 72 h, 1st and 2nd week. Significant increase in mean tail-length of DNA was observed at all time intervals after treatment with lead nitrate when compared to controls. The mean tail-length did not show a dose-related increase and the elevation in the mean tail-length was of a fluctuating type. Increase in mean tail-lengths clearly gives evidence that lead nitrate causes DNA damage effectively. The study indicates that the alkaline comet assay is a sensitive and rapid method to detect DNA damage caused by heavy metals.

Effect of various concentrations of lead nitrate on the induction of micronuclei in mouse bone marrow

The frequency of micronuclei was evaluated in the bone marrow of mice of either sex administered with 0, 0.625, 1.25, 2.5, 5, 10, 20, 40 and 80 mg/kg b.wt of lead nitrate at 12, 24 and 36 h post-treatment. The frequency of micronucleated polychromatic erythrocytes (MPCE) and micronucleated normochromatic erythrocytes (MNCE) increased significantly at 12, 24 and 36 h after treatment with lead nitrate compared to non-drug treated controls. The frequency of micronuclei did not show a dose related increase and the elevation in the frequency of micronuclei was fluctuating type. One important observation which emerged from this study was that the male mice were more sensitive to the induction of micronuclei compared to female mice. This was evidenced by higher frequencies of MPCE in males than females at all the doses for all the post-treatment time periods. The lead nitrate treatment resulted in a spurt in the erythropoiesis as is evidenced by a significant increase in the ratios of polychromatic to normochromatic erythrocytes (P/N ratio) compared to non-drug treated controls at 12, 24 and 36 h post-treatment. The P/N ratio was significantly higher in females than males at 12 and 24 h post-treatment.