Detection of micronucleus and abnormal nucleus in erythrocytes from the gill and kidney of Labeo bata cultivated in sewage-fed fish farms.

Determination of genotoxic effect in fish, micronucleus test as well as the study of the abnormal shape of nuclei is a suitable measure, in which the presence or absence of genotoxins can be detected in water. In the present study, micronuclei and abnormal nuclei frequencies were scored in the gill and kidney erythrocytes of the fish Labeo bata grown in the sewage-fed fish farms of East Calcutta wetlands. Three experimental sites were chosen, namely, Bantala, Chowbaga and Chingrihata (basically these sites have sewage-fed fishponds), which were compared with fishponds of no sewage influence as the control area. Highly significant differences (P<0.001) were noticed for micronucleus frequencies in the gill and kidney erythrocytes of experimental fishes, where kidney erythrocytes showed an increased value than gill erythrocytes without any statistical differences. The frequencies of nuclear abnormalities such as necrotic cells, apoptotic cells, notch nucleated cells and binucleated cells were also counted separately for gill and kidney erythrocytes, in which significantly (P<0.001, P<0.01, P<0.05) increased values were obtained in comparison to control populations. These genotoxicity results confirmed that the sewage-fed ponds contain genotoxic metals such as Cr, Zn, Cu, Pb, Mn, Fe through wastewater and sludge because of the direct use of sewage water without pretreatment which may lead to health risks among humans through chronic consumption of fish from these experimental fish ponds. Other vertebrates grown in sewage-fed ponds may also suffer a certain amount of genotoxic substances.     

冠状动脉支架生物相容性的系统评价

目的应用动物实验方法对聚酯聚乙烯复合膜/聚乙烯(冠状动脉支架)进行血液、遗传毒性和肌肉的生物相容性评价。方法依据ISO10993-10方法通过对家兔血液相容性试验、遗传毒性试验和肌肉植入后局部反应试验进行生物相容性评价。结果凝血酶时间(TT)、凝血酶原时间(PT)、部分凝血活酶时间(APTT)在使用支架前后无明显差异,血浆纤维蛋白原(Fg)水平在术后1～4h逐渐下降,至24h恢复正常;血小板计数从1h开始下降,至24h后逐步恢复正常。局部肌肉临床解剖和组织学观察未见异常、未见染色体发生畸变。包装材料无泄漏情况、包装材料与细菌培养基接触部位未见细菌生长。结论聚酯聚乙烯复合膜/聚乙烯(冠状动脉支架)对兔的凝血功能没有影响,由于创伤24h内对血栓形成有一定的影响,24h后对血栓形成无影响;无遗传毒性、无局部肌肉刺激反应;包装材料无泄漏、可以阻菌,延长了支架的货架期。     

Toxicological potential of 2-alkylcyclobutanones – specific radiolytic products in irradiated fat-containing food – in bacteria and human cell lines

Food irradiation has been considered as a safe processing technology to improve food safety and preservation, eliminating efficiently bacterial pathogens, parasites and insects. This study aims to characterize the toxicological potential of 2-alkylcyclobutanones (2-ACBs), radiolytic derivatives of triglycerides, formed uniquely upon irradiation of fat-containing food. In irradiated food they are generated proportionally to fat content and absorbed radiation dose.

The cyto- and genotoxic potentials of various highly pure synthetic 2-ACBs were studied in bacteria and human cell lines. While pronounced cytotoxicity was evident in bacteria, no mutagenic activity has been revealed by the Ames test in Salmonella strains TA 97, TA 98 and TA 100. In mammalian cells genotoxicity was demonstrated mainly by the induction of DNA base lesions recognized by the Fpg protein as determined by both the Comet Assay and the Alkaline Unwinding procedure. Formation of DNA strand breaks was observed by the Alkaline Unwinding procedure but not by the Comet Assay. The extent of cytotoxicity and genotoxicity were dependent on chain length and degree of unsaturation of the fatty acid chain. Further studies will have to clarify mechanisms of action and potential relevance for human exposure situation.     

Protective effects of Hibiscus tiliaceus L. methanolic extract to V79 cells against cytotoxicity and genotoxicity induced by hydrogen peroxide and tert-butyl-hydroperoxide

Plants of the genus Hibiscus thrives produce a diversity of molecules with bioactive properties. In a previous study of Hibiscus tiliaceus L. methanolic extract (HME) using bacteria and yeast, as test media, it has been shown that HME strongly inhibited the mutagenic action of H₂O₂ or tert-butyl-hydroperoxide (t-BHP). Here, our interest is to evaluate the genotoxicity and the antigenotoxic/antimutagenic properties of HME using oxidative challenge with H₂O₂ and t-BHP in V79 cells. We determined cytotoxicity using clonal survival assay; evaluated DNA damage using the comet assay and the micronucleus test in binucleated cells besides of the lipid peroxidation degree and the reduced glutathione content. We examined the ability of HME in quenching hydroxyl radical by means of a HPLC-based method utilizing the hypoxanthine/xanthine oxidase assay. At concentrations ranging from 0.001 to 0.1 mg/mL, HME was not cytotoxic, genotoxic or mutagenic. Treatment with non-cytotoxic concentrations of HME increased cell survival after H₂O₂ and t-BHP exposure and prevented DNA damage. The pre-treatment with HME also was able to decrease the mutagenic effect of these genotoxins, evaluated using the micronucleus test. HME prevented the increase in lipid peroxidation and decrease in GSH content in response to the oxidative challenge. Therefore, the ability in preventing against H₂O₂- and t-BHP-induced GSH depletion and lipid peroxidation was probably a major contribution to the cytoprotective effects. Moreover, HME acts as a hydroxyl radical scavenger. In summary, HME did not have a harmful or inhibitory effect on the growth of V79 cells and presented antioxidant activity, consequently, both antigenotoxic and antimutagenic effects against oxidative DNA damage.     

3,3''''-二氯联苯胺的急性毒性和体内遗传毒性研究

目的:研究3,3'-二氯联苯胺(DCB)的急性毒性和体内遗传毒性。方法:采用大鼠、小鼠急性毒性试验,小鼠微核试验,小鼠精母细胞染色体畸变试验和小鼠精子畸形试验。结果:经大、小鼠急性毒性试验,得DCB对大鼠、小鼠的LD50分别为4.64、3.16mg/kg,按毒性分级属微毒级物质。在小鼠微核试验中,DCB在高剂量(800mg/kg)时,能诱发小鼠嗜多染红细胞微核率升高(P<0.01);在小鼠精母细胞染色体畸变试验和小鼠精子畸形试验中,DCB在高剂量(216mg/kg)时可分别诱发小鼠精母细胞染色体畸变率和小鼠精子畸形率升高(P<0.01,P<0.01)。结论:在本实验条件下,DCB对实验动物具有一定的遗传毒性作用。     

Chlorinated river and lake water extract caused oxidative damage, DNA migration and cytotoxicity in human cells

Consumption of chlorinated drinking water is suspected to be associated with adverse health effects, including mutations and cancer. In the present study, the genotoxic potential of water from Donghu lake, Yangtze river and Hanjiang river in Wuhan, an 8-million metropolis in China, was investigated using HepG2 cells and the alkaline version of the comet assay. It could be shown that all water extracts caused dose-dependent DNA migration in concentrations corresponding to dried extracts of 0.167–167 ml chlorinated drinking water per ml medium. To explore whether the intracellular redox status is regulated by chlorinated drinking water, we determined lipid peroxidation (LPO) and depletion of reduced glutathione (GSH). The malondialdehyde (thiobarbituric acid (TBA)-reactive aldehydes) concentration increased after chlorinated drinking water treatment of HepG2 cells in a dose-dependent manner, the GSH content decreased. The activity of lactate dehydrogenase (LDH) increased in chlorinated drinking water treated HepG2 cells indicating cytotoxicity. In accordance with former studies which dealt with in vivo and in vitro micronucleus induction the present study shows that chlorinated drinking water from polluted raw water may entail genetic risks.     

Genotoxicity of PM10 and extracted organics collected in an industrial, urban and rural area in Flanders, Belgium

The variation in the genotoxic potency of PM10 in vitro in relation to the particle source type was investigated. Particles were collected at one urban, one rural, and one industrial site in Flanders. Genotoxicity was assessed using four different in vitro test systems exposed to PM10 in suspension and to the organic extracts of PM10. Two of these systems were bacterial assays: the Salmonella mutagenicity test and the Vitotox test. In addition, the Comet assay and Micronucleus test were performed using human blood cells. Results show that exposure to PM10 and the organic extracts from both urban and industrial areas causes significant genetic damage. The Salmonella mutagenicity test was most suitable for the screening of PM10 and the organic extracts; the Micronucleus test was most suitable only for the screening of organic extracts, and original particles were toxic for the exposed lymphocytes. Clear dose-response curves were not established in the Comet and Vitotox assay, and organic extracts were apparently toxic in the latter. The total polycyclic aromatic hydrocarbon content of the organic extracts, as measured with GC/MS, ranged between 1 and 6 ng/m3. Results obtained in this study suggest that PM10 causes DNA damage and mutations. The use of biological tests for the screening of air samples is useful to complement air quality control by chemical measurements.     

Dicentrarchus labrax biotransformation and genotoxicity responses after exposure to a secondary treated industrial/urban effluent

The present research work was designed to study Dicentrarchus labrax (sea bass) biotransformation and genotoxicity responses to the soluble fraction of a secondary treated industrial/urban effluent (SF-STIUE) discharged through a submarine pipe outlet into the Aveiro coastal area. Sea bass was exposed for 4, 8, 16, 24, 48, and 96 h to 0%, 0.1%, and 1% SF-STIUE and the following biological responses were measured: (1) liver cytochrome P450 (P450) content and ethoxyresorufin-O-deethylase (EROD) activity, as phase I biotransformation parameters; (2) liver gluthathione S-transferase (GST) activity as a phase II conjugation enzyme; (3) biliary and liver cytosol naphthalene (Naph)- and benzo(a)pyrene (B(a)P)-type metabolites, by fixed wavelength fluorescence detection (FF); (4) liver DNA strand breaks, erythrocytic micronuclei (EMN), and erythrocytic nuclear abnormalities (ENA) as genotoxicity parameters. Both SF-STIUE dilutions (0.1% and 1%) failed to significantly increase liver EROD activity, despite a significant increase of liver P450 at 16 and 48 h exposure to 0.1%. Liver GST activity increased significantly at 4h of sea bass exposure to 1% SF-STIUE, being inhibited at 96 h of exposure to this SF-STIUE dilution. Naph- and B(a)P-type metabolite contents were not significantly increased in bile. However, Naph-type metabolite contents increased significantly in liver cytosol at 4h exposure to 1% SF-STIUE, and at 24h exposure to 0.1% and 1% SF-STIUE. Furthermore, B(a)P-type metabolites increased significantly in liver cytosol at 4h exposure to 1% SF-STIUE, and 16 h exposure to 0.1% and 1% SF-STIUE. EMN and ENA frequencies increased significantly at 4, 8, 16, 24, 48, and 96 h exposure to 0.1% and 1% SF-STIUE. Liver DNA integrity decreased significantly at 96 h of sea bass exposure to 1% SF-STIUE. The STIUE discharged into Aveiro coastal area is of great ecotoxicological concern due to its genotoxic potential.     

Investigation of the role of the 2',3'-epoxidation pathway in the bioactivation and genotoxicity of dietary allylbenzene analogs

The genotoxic potential of naturally occurring allylbenzene analogs, including safrole, eugenol, estragole, and others, has been examined in many studies over the past 30 years. It has been established that these compounds are subject to biotransformation in the liver, which can lead to the formation of reactive electrophilic intermediates. The major route of bioactivation is via hydroxylation of the 1′ carbon atom of the allylic side chain. We have synthesized 2′,3′- (allylic) epoxide derivatives of allylbenzene, estragole eugenol and safrole, and have used them to characterize the genotoxic potential of epoxidation at the allylic double bond for allylbenzene and its naturally occurring analogs. In order to assert that this pathway has the potential for genotoxicity, it is necessary to demonstrate (1) that epoxide metabolites of these compounds are capable of forming covalent adducts with DNA bases; and (2) that these epoxide metabolites are actually formed in vivo. We have demonstrated that allylic epoxides derived from allylbenzene and estragole are capable of forming covalent adducts with all four deoxyribonucleotides in vitro and, in the case of deoxyguanosine, form at least four different adducts. We also deduce, from evidence obtained using the isolated perfused rat liver, that formation of potentially genotoxic 2′,3′ epoxide metabolites occurs readily in vivo, but that these metabolites are rapidly further metabolized to less toxic dihydrodiol or glutathione conjugates. We conclude that 2′,3′ epoxide metabolites of allylbenzene analogs are formed in vivo and that these epoxides are sufficiently reactive to facilely form covalent bonds with DNA bases. Epoxide formation at the allylic double bond represents, therefore, a potentially genotoxic bioactivation pathway for allylbenzene analogs. However, comparison of the relative kinetics of epoxide metabolism and epoxide formation suggests that a wide margin of protection from DNA covalent adduct formation exists in the rat liver, thus preventing genotoxicity resulting from this pathway to any significant degree. In this regard, we have also observed that the general rate of epoxide hydrolysis is much greater in human liver than in rat liver. We therefore suggest that while the epoxidation pathway poses a potential genotoxic threat to humans, no actual genotoxicity occurs as a result of this metabolic pathway.     

Review of the Toxicology of Three Alkyl Diamines

Three alkyl diamines, which are by-products formed and separated during the production of hexamethylene diamine, have been tested, mostly for their acute toxicity. This paper reviews methodologies used and the results obtained from these three chemicals. All three tested [2-methyl-1,5-pentanediamine (2-MP), 1,3-diaminopentane (DAMP), and 1,2-cyclohexanediamine (DCH)] were 95% pure and were supplied by the DuPont Company. The acute toxicity of all three chemicals is relatively low with acute oral lethal levels in the rat ranging from 1000 to 2300 mg/kg. Single 4-h inhalation exposures show similarly low toxicity with lethality produced in the rat at concentrations ranging from 2.9 to 4.3 mg/L. These diamines are severe skin irritants in both the rabbit and the guinea pig and are also severe eye irritants (studied only in 2-MP). Dermal sensitization was seen in the guinea pig with DAMP and DCH but not with 2-MP. The irritant dose of these materials was shown in repeated exposure inhalation studies when 2-MP and DCH produced irritation in the upper respiratory tract (point of contact) with some lower lung involvement but no significant systemic effects. 2-MP when fed to rats produced a slight body weight effect at dose equivalents of 800 mg/kg with no other parameters affected. All three materials were inactive in Salmonella, and 2-MP did not produce chromosomal aberrations in cultured human lymphocytes. The main effects of this series of diamines appear related to their irritant properties, and attention needs to be paid to their delayed hypersensitivity potential.