Genetic toxicology studies with glutaraldehyde.

Glutaraldehyde (GA; CAS no. 111-30-8) has a wide spectrum of industrial, scientific and biomedical applications, with a potential for human exposure particularly in its biocidal applications. The likelihood for genotoxic effects was investigated in vitro and in vivo. A Salmonella typhimurium reverse mutation assay showed no evidence for mutagenic activity with strains TA98, TA1535, TA1537 and TA1538, with or without metabolic activation. However, there was a weak mutagenic response (1.9-2.3-fold at the highest non-toxic concentration) with TA100 in the presence of metabolic activation. In a Chinese hamster ovary (CHO) forward gene mutation assay (HGPRT locus) there were no consistent, statistically significant, reproducible or dosage-related increases in the frequency of 6-thioguanine resistant cells. There were no reproducible or dosage-related increases in sister chromatid exchanges in an in vitro test in CHO cells. An in vitro cytogenetics study in CHO cells showed no evidence for an increase in chromosomal aberrations on treatment with GA, either in the presence or absence of metabolic activation. In vivo, a mouse peripheral blood micronucleus test showed no increase in micronucleated polychromatophils at sampling times of 30, 48 and 72 h after acute gavage dosing with GA at 40, 80 and 125 mg kg(-1) (corresponding to 25, 50 and 85% of the LD(50)). The absence of an in vivo clastogenic potential was confirmed by no increase in chromosomal aberrations in a rat bone marrow cytogenetics study with sampling at 12, 24 and 48 h after acute gavage dosing with GA (12.5, 30 or 60 mg kg(-1) with males, and 7.5, 20 or 40 mg kg(-1) with females). Thus, in this series of tests, GA produced genotoxic effects in vitro only in a bacterial reverse mutation assay with no evidence for in vivo genotoxicity.     

甲基叔丁基醚遗传毒性研究

甲基叔丁基醚（ＭＴＢＥ）是一种新型的汽油添加剂，被用来提高汽油辛烷值和减少汽车尾气中有害物质的排放。我们采用Ａｍｅｓ试验、程序外ＤＮＡ合成（ＵＤＳ）试验和细胞微核试验等反映不同遗传学终点的系列试验，检测了国产ＭＴＢＥ的遗传毒性。在Ａｍｅｓ试验（ＴＡ９８和ＴＡ１００菌株）中，在加和不加Ｓ－９的情况下，ＭＴＢＥ均未表现出致突变性。大鼠肝细胞ＵＤＳ试验显示，ＭＴＢＥ具有轻微的ＤＮＡ损伤作用。在ＮＩＨ３Ｔ３细胞微核试验中，ＭＴＢＥ呈现阴性结果。上述结果提示，ＭＴＢＥ在ＤＮＡ水平具有一定的遗传毒性     

氯化锂对小鼠生殖和胚泡细胞遗传毒性的研究

目的：观察氯化锂的遗传毒性特征并对其毒作用机制做一切初步探讨。方法：以氯化锂为受试物,昆明种小鼠为受试对象,进行小鼠生殖细胞遗传毒性试验。结果：氯化锂经口灌胃染毒后,小鼠睾丸细胞染色体畸变率增加,着床前胚泡细胞微核率增加,结论：一定剂量的氯化锂对小鼠生殖和胚泡细胞具有遗传性毒性用。     

危险品货运站空气污染物对DNA的损伤作用

目的探讨危险品货运站空气污染物的DNA损伤作用。方法应用SOS/umu试验,大鼠肺Ⅱ型细胞的DNA交联试验和单细胞凝胶电泳试验,检测危险品货运站空气污染物对DNA的损伤情况。结果空气污染物在81,163,325,650μg/10μl的剂量范围,不加S9活化系统的条件下,污染物显示遗传毒性,存在剂量-反应关系(r=0.994,P<0.01);加入S9活化系统后,污染物未显示出遗传毒性。在1.02,2.03,4.06,8.13 mg/ml的剂量范围内,污染物能引起大鼠肺Ⅱ型细胞DNA产生双链间的交联和单链断裂,存在剂量-反应关系(r交联=0.981,r断裂=0.987,P<0.01)。结论危险品货运站空气污染物具有DNA损伤作用。     

Single-Dose Toxicity of Individual and Combined Sterigmatocystin and 5-Methoxysterigmatocistin in Rat Lungs

Sterigmatocystin (STC) and 5-methoxysterigmatocystin (5-M-STC) are mycotoxins produced by common damp indoor Aspergilli series Versicolores. Since both STC and 5-M-STC were found in the dust of indoor occupational and living areas, their occupants may be exposed to these mycotoxins, primarily by inhalation. Thus, STC and 5-M-STC were intratracheally instilled in male Wistar rats using doses (0.3 mg STC/kg of lung weight (l.w.); 3.6 mg 5-M-STC/kg l.w.; toxin combination 0.3 + 3.6 mg/kg l.w.) that corresponded to concentrations detected in the dust of damp indoor areas in order to explore cytotoxicity, vascular permeability, immunomodulation and genotoxicity. Single mycotoxins and their combinations insignificantly altered lactate-dehydrogenase activity, albumin, interleukin-6, tumor necrosis factor-α and chemokine macrophage inflammatory protein-1α concentrations, as measured by ELISA in bronchioalveolar lavage fluid upon 24 h of treatment. In an alkaline comet assay, both mycotoxins provoked a similar intensity of DNA damage in rat lungs, while in a neutral comet assay, only 5-M-STC evoked significant DNA damage. Hence, naturally occurring concentrations of individual STC may induce DNA damage in rat lungs, in which single DNA strand breaks prevail, while 5-M-STC was more responsible for double-strand breaks. In both versions of the comet assay treatment with STC + 5-M-STC, less DNA damage intensity occurred compared to single mycotoxin treatment, suggesting an antagonistic genotoxic action.     

益母草碱对胚胎-胎仔发育毒性和遗传毒性的评价

目的 检测益母草碱的发育毒性和遗传毒性。方法 在SD孕鼠妊娠第6~15天经口灌胃给予500、1 000和2 000 mg/kg体重的益母草碱,同时设溶媒对照组,经口灌胃0.5% CMC-Na溶液。妊娠第20天剖杀孕鼠,分析其生殖毒性。分别采用反映基因突变的鼠伤寒沙门菌回复突变试验（Ames试验）、反映染色体畸变的细胞染色体畸变试验（体外培养CHO）和ICR小鼠骨髓微核试验（体内）检测益母草碱的遗传毒性。结果 在500、1 000和2 000 mg/kg剂量益母草碱的作用下孕鼠的增重与对照组相比,差异均无统计学意义;各受试剂量组孕鼠各项指标与对照组相比,差异均无统计学意义;各剂量组胎鼠各类指标与溶媒对照组相比,无明显差异。Ames试验结果提示：在0.5、5、50、500、5 000 μg/皿受试剂量下,在有或无代谢活化S9系统时,与溶媒对照组相比,受试物对组氨酸缺陷型鼠伤寒沙门菌（TA97、TA98、TA100、TA102及TA1535）所诱发的回复突变菌落数均相近。染色体畸变试验结果显示：250、500和1 000 μg/ml 3个剂量的受试物,对有或无代谢活化系统S9培养的CHO细胞的染色体畸变率无明显影响。微核试验显示100、500和2 000 mg/kg各个剂量组对ICR小鼠的微核诱发率与溶媒对照组比较均无显著差异（P>0.05）。结论 益母草碱在500、1 000和2 000 mg/kg剂量下未观察到明显的母体毒性、胚胎毒性、胎儿毒性和致畸作用。益母草碱对鼠伤寒沙门菌无致突变性,对哺乳动物培养细胞的染色体无致畸变作用,对ICR小鼠无诱发骨髓嗜多染红细胞微核的效应。上述结果表明在本试验条件下,益母草碱无发育和遗传毒性。     

Genetic toxicity assessment using liver cell models: past,present, and future

ABSTRACT

Genotoxic compounds may be detoxified to non-genotoxic metabolites while many pro-carcinogens require metabolic activation to exert their genotoxicity in vivo. Standard genotoxicity assays were developed and utilized for risk assessment for over 40 years. Most of these assays are conducted in metabolically incompetent rodent or human cell lines. Deficient in normal metabolism and relying on exogenous metabolic activation systems, the current in vitro genotoxicity assays often have yielded high false positive rates, which trigger unnecessary and costly in vivo studies. Metabolically active cells such as hepatocytes have been recognized as a promising cell model in predicting genotoxicity of carcinogens in vivo. In recent years, significant advances in tissue culture and biological technologies provided new opportunities for using hepatocytes in genetic toxicology. This review encompasses published studies (both in vitro and in vivo) using hepatocytes for genotoxicity assessment. Findings from both standard and newly developed genotoxicity assays are summarized. Various liver cell models used for genotoxicity assessment are described, including the potential application of advanced liver cell models such as 3D spheroids, organoids, and engineered hepatocytes. An integrated strategy, that includes the use of human-based cells with enhanced biological relevance and throughput, and applying the quantitative analysis of data, may provide an approach for future genotoxicity risk assessment.     

Use of Comet and Micronucleus Assays to Measure Genotoxicity in Meadow Voles (<Emphasis Type="BoldItalic">Microtus pennsylvanicus</Emphasis>) Living in Golf Course Ecosystems Exposed to Pesticides

The purpose of this study was to conduct a biomonitoring study to measure the effects of pesticide exposure in meadow voles (Microtus pennsylvanicus) living in golf courses of the Ottawa/Gatineau region of Canada. In this article we present the results from the comet and micronucleus assay. Voles were captured in 2001 and 2002 at five golf courses and two reference sites. Blood was collected from sedated voles. Three animals from each course were euthanized to determine body burdens of historically used organochlorine (OC) and metal-based pesticides. Exposure to in-use pesticides was determined from detailed golf course pesticide use records. Comet tail length and tail moment were not related to body burdens of OC pesticides and metals historically used on these golf courses. In generally, tail length and moment significantly decreased in relation to days since last application of a pesticide, and to days since the last application of a specific fungicide (Daconil^®) containing a potentially genotoxic active ingredient (chlorothalonil). The slopes of these curves in 2002 were not significantly different than the half-life decay curve of chlorothalonil on vegetation. Both comet assay parameters appeared to increase in a dose-dependent manner with the amount of the last application Daconil^®. The number of micronucleated polychromatic erythrocytes was not related to any pesticide application parameter.     

The application of the cytokinesis-block micronucleus assay on peripheral blood lymphocytes for the assessment of genome damage in long-term residents of areas with high radon concentration

Estimating the effects of small doses of ionising radiation on DNA is one of the most important problems in modern biology. Different cytogenetic methods exist to analyse DNA damage; the cytokinesis-block micronucleus assay (CBMN) for human peripheral blood lymphocytes is a simple, cheap and informative cytogenetic method that can be used to detect genotoxic-related markers. With respect to previous studies on radiation-induced genotoxicity, children are a poorly studied group, as evidenced by the few publications in this area. In this study, we assessed radon genotoxic effects by counting micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) in the lymphocytes of children who are long-term residents from areas with high radon concentrations. In the exposed group, radon was found to cause significant cytogenetic alterations. We propose that this method can be employed for biomonitoring to screen for a variety of measures.     

Role of surface charge and oxidative stress in cytotoxicity and genotoxicity of graphene oxide towards human lung fibroblast cells

Recently, attempts have been made to apply graphene oxide (GO) in the field of biology and medicine, such as DNA sensing and drug delivery with some necessary modifications. Therefore, the toxicity of GO must be evaluated before it is applied further in biomedicine. In this paper, the cytotoxicity and genotoxicity of GO to human lung fibroblast (HLF) cells have been assessed with methyl thiazolyl tetrazolium (MTT), sub‐G1 measurement and comet assays, and the mechanism of its toxicity has been explored. Various modifications of GO have been made to help us determine the factors which could affect the toxicity of GO. The results indicated that cytotoxicity and genotoxicity of GO to HLF cells were concentration dependent, and the genotoxicity induced by GO was more severe than the cytotoxicity to HLF cells. Oxidative stress mediated by GO might explain the reason of its toxic effect. Furthermore, the electronic charge on the surface of GO would play a very important role in the toxicity of GO to HLF cells. Copyright © 2013 John Wiley & Sons, Ltd.