Genotoxic effects of arsenic: prevention by functional food-jaggery

Arsenic contamination in groundwater is global human health hazard. There is no effective remedial action of chronic arsenicosis, however, a well-nourished diet can modulate the onset of adverse health effects and the delayed effect of arsenic in drinking water. In the present work, genotoxic effects induced by arsenic through parenteral administration and ameliorate by jaggery. Chromosomal aberrations were more pronounced in arsenic treated mice, while supplementation of jaggery with arsenic reduced the incidence of the aberrations. The outcome of study showed that Jaggery the natural functional food has the efficiency to encounter the genotoxic effects induced by arsenic.     

涑水河闻喜河段污水及其沿岸井水遗传毒物污染状况的研究

目的与方法 :应用蚕豆和大蒜根尖细胞微核技术对涑水河闻喜河段污水及其沿岸井水遗传毒物的污染状况进行了检测。结果 :蚕豆检测结果表明 ,涑水河闻喜河段 5个采样点河水都受到了遗传毒物的污染 ,污染程度依次为东桥 >吕庄水库 >店头>孙村 >苏村 ;在近岸 5个样点中店头、孙村、吕庄水库和东桥 4个样点的井水被污染 ,在远岸 5个样点中吕庄水库和东桥 2个样点的井水被污染。用大蒜检测河水的结果与蚕豆检测的结果一致 ,呈高度正相关 (r =0 .95 0 3,P <0 .0 1)。大蒜检测沿岸井水的结果表明 ,近岸的店头和东桥 2个样点的井水被污染 ,远岸的东桥样点的井水被污染 ,与蚕豆检测结果呈正相关 (r=0 .8790 ,P <0 .0 2 5 )。结论 :以上结果显示 ,涑水河闻喜河段河水及其沿岸的部分井水均受到了遗传毒物不同程度的污染。大蒜可作为检测细胞遗传损伤的植物加以开发利用。     

Antimutagenic potential of the Thai herb, Mucuna collettii Lace

Mucuna collettii Lace is a Thai herb with a long record of consumption among mature Thai males for the promotion of sexual potency. The mutagenic and antimutagenic potentials of Mucuna collettii extract were carried out by using the Ames test pre-incubation method in the presence and absence of S9 mixture. Salmonella typhimurium strains TA 98 and TA 100 were applied as the tester strains. Prior to mutagenic and antimutagenic tests, the survival of the tester strains was performed by treating with the plant extract. Results showed Mucuna collettii extract exhibited strong cytotoxic effects in a dose-dependent manner. Toxicity of the plant was confirmed in mice in which negative adverse effect was found in kidney, uterus, ovary, and testis. Mucuna collettii extract in the presence and absence of S9 mixture was negative for mutagenic Ames test. Mucuna collettii extract in the presence and absence of S9 mixture was positive for antimutagenic Ames test towards either one or both of the tested mutagens: 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (AF-2) and benzo(a)pyrene. The antimutagenic activity of the plant extract was confirmed in rec-assays. Micronucleus test demonstrated that Mucuna collettii extract at high dose and a long incubation time could induce micronucleus formation in tested animals, but less than the response of the positive control. The overall mutagenic and antimutagenic assays are further evidences for the antimutagenic potential of Mucuna collettii.     

In vitro study of mutagenic potential of Bidens pilosa Linné and Mikania glomerata Sprengel using the comet and micronucleus assays

Teas of Bidens pilosa and Mikania glomerata are popularly consumed to medicinal ends. The capacity to induce DNA damages and mutagenic effects of these teas were evaluated, in vitro, on HTC cells, with comet assay and micronucleus test. The teas tested at various doses were prepared differently: infusion of Mikania glomerata (IM) and Bidens pilosa (IB), macerate of Mikania glomerata in 80% ethanol (MM80) and decoction of Bidens pilosa (DB). In IM and MM80, the quantity of coumarin was determined by high-performance liquid chromatography (HPLC) with UV detection. Methylmethanesulfonate was utilized as positive control, phosphate-buffered saline as negative control, 80% ethanol as solvent control and 2-aminoanthracene as drug metabolism control. The comet assay demonstrated genotoxic effects for both plants. The genotoxic potential of IB was upper than DB, showing dose-response. In the MN test, excepting IM 40 microL/mL, all treatments was not mutagenic. The effects did not show direct relation with cumarin quantity present in IM and MM80. The results demonstrated DNA damages at the highest concentrations of alcoholic macerate (10 and 20 microL/mL) and infusion of Mikania glomerata (20 and 40 microL/mL) and of Bidens pilosa infusion (40 microL/mL). Thus, both dose and preparation-form suggest caution in the phytotherapeutic use of these plants.     

Oxidative stress and genotoxicity in Rhinella arenarum (Anura: Bufonidae) tadpoles after acute exposure to Ni-Al nanoceramics

The employ of nanomaterials (NMs) has exponentially grown due to the large number of technological advances in industrial, pharmaceutical and medical areas. That is the case of alumina (Al) nanoparticles which are extensively employed as support in heterogeneous catalysis processes. However, these NMs can cause great toxicity because of their ubiquitous properties, such as extremely small size and high specific surface area. So, it is required to assess the potential deleterious effects of these NMs on living organisms. In the present study, we analyze the oxidative stress and genotoxic potential of a nanoceramic catalyst Ni/<gamma>-Al₂O₃ (NC) and the NMs involved in their synthesis, <gamma>-Al₂O₃ support (SPC) and NiO/<gamma>-Al₂O₃ precursor (PC) on Rhinella arenarum larvae. Biomarkers of oxidative stress and genotoxic damage were measured in tadpoles exposed to 5 and 25 mg/L of each NMs for 96 h. The results indicated an inhibition of catalase activity in tadpoles exposed to both concentrations of PC and to 25 mg/L of SPC and NC. Moreover, both exposure concentrations of PC and NC significantly inhibited superoxide dismutase activity. Exposure to the three NMs caused inhibition of glutathione S-transferase activity, but there were no significant variations in reduced glutathione levels. Oxidative stress damage (lipid peroxidation) was observed in tadpoles treated with 25 mg/L PC, while the other treatments did not produce alterations. The MNs frequency significantly increased in larvae exposed to 25 mg/L PC indicating irreversible genotoxic damage. The results show that these NMs exert genotoxic effects and antioxidant defense system disruption in R. arenarum larvae.     

石棉纤维间接作用的细胞毒性及遗传毒性

目的 探讨石棉纤维与培养的人肺泡上皮细胞间接作用（纤维不与细胞直接接触）后的细胞毒性和遗传毒性，以及活性氧在其中的作用。方法 用固体作用物与培养细胞隔开的TRANSWELL培养板，观察由国际抗癌团体（UICC）提供标准温石棉对人肺泡上皮（A549）细胞间接作用及直接作用不同时间后的细胞毒性和遗传毒性。同时，在染毒过程中分别加入活性氧清除剂[过氧化氢酶（CAT）细胞间接作用及直接作用不同时间后的细胞毒性和遗传毒性。同时，在染毒过程中分别加入活性氧清除剂[过氧化氢酶（CAT），超氧化物歧化酶（SOD），甘露醇（Mannitol)]，以观察活性氧在石棉间接作用引起的细胞毒性及遗传毒性中的影响。结果 UICC温石棉纤维直接与A549细胞接触，作用24h,在40μg/ml时可引起细胞存活率明显下降，而石棉纤维间接与细胞作用24h，则在80μg/ml时才引起细胞存活率的明显下降，在石棉直接作用时，3种抗氧化剂均可部分抑制石棉导致的细胞存活率下降，但均未抑制到对照组水平；而在石棉间接作用时，3种抗氧化剂均可完全抑制石棉纤维导致的细胞存活率下降，UICC温石棉纤维直接与A549细胞接触，作用24h，在10μg/ml时即可明显引起细胞DNA链断裂，而石棉纤维间接与细胞作用24h，即使在80μg/ml时也未能引起细胞DNA链断裂程度的明显增加。而当较高浓度的温石棉与A549细胞间接作用3h，均可引起细胞DNA链断裂的明显增加，3种抗氧化剂均可明显抑制石棉纤维导致的细胞DNA链断裂，其中，甘露醇和SOD可完全抑制石棉的这种损伤作用。结论 石棉纤维在不与细胞直接接触时也可通过其表面产生的活性氧造成靶细胞损伤和遗传物质的损伤，该研究结果可为对石棉采取表面改性以降低石棉纤维的毒性提供理论依据。     

On the bioactivation and genotoxic action of fluoranthene

Fluoranthene (FA) was studied with respect to possible mechanisms of its high mutagenicity but low carcinogenicity, in comparison with the corresponding properties of benzo[a]pyrene (BaP), and with regard to the synergism of these two compounds shown by van Duuren and Goldschmidt (J Natl Cancer Inst 56, 1976, 1237). FA and BaP activated by S9 from Aroclor 1254 (PCB)-treated rats induce HPRT mutations in CHO cells with about equal effectiveness at the same exposure doses, which also lead to the same frequencies of repairable DNA adducts, enzyme-induced strand breaks being used as an indirect measure of adducts to DNA. FA was also shown to be an efficient inducer of SCE in human peripheral lymphocytes cocultivated with PCB-treated HepG2 cells or with liver cells from PCB-pretreated rats. For the induction of SCE, FA and BaP were shown to act additively. From metabolic studies with liver microsomes from C57B1/6 mice it is concluded that, whereas BaP induces the metabolism of BaP to the mutagenic epoxide, neither BaP nor FA is able to induce the metabolism of FA. In mutation experiments with V79 cells (XEM2) constitutive for P450 IA1 activity, BaP 7,8-diol but not FA 2,3-diol provokes a high frequency of HPRT mutations. In cells constitutive for P450 IA2 enzymatic activity FA and BaP are but weakly mutagenic and practically nonmutagenic, respectively. Due to the additivity of the genotoxic effects of FA and BaP, induction of an error-prone condition by the latter compound seems to be excluded. It therefore appears that for an explanation of the difference in carcinogenic potency between FA and BaP, indications that BaP but not FA acts as a promoter should be studied further.     

甲状腺素对甲亢女性患者淋巴细胞的遗传毒性研究

目的：研究甲状腺素对甲亢女性患者的遗传学毒性作用。方法：利用细胞松弛素－B抑制细胞的胞质分裂的实验方法,促使体外培养的血细胞产生双核淋巴细胞微核。结果：甲亢缓解患者的培养淋巴细胞经激素诱导和未经激素诱导两组的双核淋巴细胞的微核率相比较具有显著性的差异（P＜001）且激素诱导组有异常微核的为25例。结论：甲状腺素可诱导患者淋巴细胞的微核率升高,全血培养的双核淋巴细胞微核率能反映出甲状腺素对细胞内DNA的毒性作用。     

Co-exposure of iron oxide nanoparticles and glyphosate-based herbicide induces DNA damage and mutagenic effects in the guppy (Poecilia reticulata)

Iron oxide nanoparticles (IONPs) have been tested to remediate aquatic environments polluted by chemicals, such as pesticides. However, their interactive effects on aquatic organisms remain unknown. This study aimed to investigate the genotoxicity and mutagenicity of co-exposure of IONPs (γ-Fe₂O₃ NPs) and glyphosate-based herbicide (GBH) in the fish Poecilia reticulata. Thus, fish were exposed to citrate-functionalized γ-Fe₂O₃ NPs (0.3 mg L⁻¹; 5.44 nm) alone or co-exposed to γ-Fe₂O₃ NPs (0.3 mg L⁻¹) and GBH (65 and 130 μg of glyphosate L⁻¹) during 14 and 21 days. The genotoxicity (DNA damage) was analyzed by comet assay, while the mutagenicity evaluated by micronucleus test (MN test) and erythrocyte nuclear abnormalities (ENA) frequency. The co-exposure induced clastogenic (DNA damage) and aneugenic (nuclear alterations) effects on guppies in a time-dependent pattern. Fish co-exposed to NPs and GBH (130 μg glyphosate L⁻¹) showed high DNA damage when compared to NPs alone and control group, indicating synergic effects after 21 days of exposure. However, mutagenic effects (ENA) were observed in the exposure groups after 14 and 21 days. Results showed the potential genotoxic and mutagenic effects of maghemite NPs and GBH co-exposure to freshwater fish. The transformation and interaction of iron oxide nanoparticles with other pollutants, as herbicides, in the aquatic systems are critical factors in the environmental risk assessment of metal-based NPs.     

Single-cell gel electrophoresis (SCG)-A review and discussion

Single-cell gel electrophoresis (SCG) is a simple, sensitive and effective technique. Being able to reflect quantitatively the genotoxicity of many hazardous agents, it is promising for application in environmental genotoxic monitoring and the study of carcinogenesis. In clinics, it can be used to evaluate the DNA repair ability and monitor DNA breaks during cancer therapy. As a biomarker, it has its own merits and limitations, being different from other biomarkers such as sister chromatid exchange (SCE) test and micronuclei (MN) assay. In many studies, it is more sensitive than SCE or MN. Combination studies with other biomarkers like SCE, MN, chromosomal aberration, bcl-2 and genetic polymorphisms have begun to demonstrate its great importance for the understanding of carcinogenesis and the genotoxicities of environmental factors.