Effects of indirubin and isatin on cell viability,mutagenicity, genotoxicity and BAX/ERCC1 gene expression

Context: Indigofera suffruticosa Miller (Fabaceae) and I. truxillensis Kunth produce compounds, such as isatin (ISA) and indirubin (IRN), which possess antitumour properties. Their effects in mammalian cells are still not very well understood.

Objective: We evaluated the activities of ISA and/or IRN on cell viability and apoptosis in vitro, their genotoxic potentials in vitro and in vivo, and the IRN- and ISA-induced expression of ERCC1 or BAX genes.

Materials and methods: HeLa and/or CHO-K1 cell lines were tested (3 or 24?h) in the MTT, Trypan blue exclusion, acridine orange/ethidium bromide, cytokinesis-blocked micronucleus (CBMN) and comet (36, 24 and 72?h) tests after treatment with IRN (0.1 to 200?μM) or ISA (0.5 to 50?μM). Gene expression was measured by RT-qPCR in HeLa cells. Swiss albino mice received IRN (3, 4 or 24?h) by gavage (50, 100 and 150?mg/kg determined from the LD₅₀ – 1?g/kg b.w.) and submitted to comet assay in vivo.

Results: IRN reduced the viability of CHO-K1 (24?h; 5 to 200?μM) and HeLa cells (10 to 200?μM), and was antiproliferative in the CBMN test (CHO-K1: 0.5 to 10?μM; HeLa: 5 and 10?μM). The drug did not induce apoptosis, micronucleus neither altered gene expression. IRN and ISA were genotoxic for HeLa cells (3 and 24?h) at all doses tested. IRN (100 and 150?mg/kg) also induced genotoxicity in vivo (4?h).

Conclusion: IRN and ISA have properties that make them candidates as chemotherapeutics for further pharmacological investigations.     

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.     

Application of the buccal micronucleus cytome assay and analysis of PON1Gln192Arg and CYP2A6*9(−48T>G) polymorphisms in tobacco farmers

Tobacco is a major Brazilian cash crop. Tobacco farmers apply large amounts of pesticides to control insect growth. Workers come into contact with green tobacco leaves during the tobacco harvest and absorb nicotine through the skin. In the present study, micronucleus frequency, cell death, and the frequency of basal cells were measured in tobacco farmers using the buccal micronucleus cytome assay (BMCyt), in parallel with measurement of blood butyrylcholinesterase (BChE) and nicotine levels. Polymorphisms in PONIGln192Arg and CYP2A6*9(?48T>G) were evaluated to verify the relationship between genetic susceptibility and the measured biomarkers. Peripheral blood and buccal cell samples were collected from 106 agricultural workers, at two different crop times (during pesticide application and leaf harvest), as well as 53 unexposed controls. BMCyt showed statistically significant increases in micronuclei, nuclear buds, and binucleated cells among exposed subjects in differentiated cells, and in micronuclei in basal cells. In addition, the exposed group showed higher values for condensed chromatin, karyorrhectic, pyknotic, and karyolitic cells, indicative of cell death, and an increase in the frequency of basal cells compared to the unexposed control group. A slight difference in mutagenicity using the BMCyt assay was found between the two different sampling times (pesticide application and leaf harvest), with higher micronucleus frequencies during pesticide application. Elevated cotinine levels were observed during the leaf harvest compared to the unexposed controls, while BChE level was similar among the farmers and controls. PONIGln192Arg and CYP2A6*9(?48T>G) polymorphisms were associated with DNA damage induced by pesticides and cell death. Environ. Mol. Mutagen., 2012. © 2012 Wiley Periodicals, Inc.     

The role of urinary pH in o‐phenylphenol‐induced cytotoxicity and chromosomal damage in the bladders of F344 rats

o‐Phenylphenol (OPP) is a widely used fungicide and antibacterial agent that at high doses has been shown to cause bladder cancer in male F344 rats. The mechanisms underlying OPP‐induced bladder carcinogenicity remain unclear but it has been proposed that a non‐enzymatic pH‐dependent autoxidation of phenylhydroquinone (PHQ), a primary metabolite of OPP, may be a key step in OPP‐induced rat bladder carcinogenesis. To investigate this mechanism and to provide insights into the potential human health relevance of OPP‐induced cancer, a series of in vitro and in vivo experiments were conducted. In human lymphoblastoid TK‐6 cells and rat bladder epithelial NBT‐II cells, strong increases in cytotoxicity were seen at a constant concentration of PHQ by increasing the buffer pH as well as by increasing concentrations of PHQ at a constant pH. In in vivo studies, male rats were administered OPP (4,000 and 8,000 ppm) in a diet supplemented with either 1% ammonium chloride or 3% sodium bicarbonate to produce acidic and alkaline urinary pH, respectively. Significant increases in cell proliferation as detected by 5‐bromo‐2′‐deoxyuridine incorporation and micronucleus formation were seen in the bladder cells of OPP‐treated rats with neutral or alkaline urinary pH but not in animals with the acidified urine. The results from these in vitro and in vivo studies provide support for the autoxidation hypothesis of bioactivation, and provide additional evidence that urinary pH can significantly influence the genotoxicity and carcinogenicity of this important agent. Environ. Mol. Mutagen. 57:210–219, 2016. © 2016 Wiley Periodicals, Inc.     

脾胃湿热证胃炎患者舌苔脱落细胞中微核细胞及P53表达

[目的]探讨脾胃湿热证和脾气虚证慢性浅表性胃炎患者舌苔脱落细胞微核细胞和P53表达的意义.[方法]用Feulgen法和免疫细胞化学法显示正常对照者及脾胃湿热和脾气虚患者舌苔脱落细胞中微核细胞、P53表达.[结果]脾胃湿热组和脾气虚组微核细胞的反应强度及出现频率均高于正常对照组(均P＜0.05);脾气虚组的P53阳性反应高于正常对照组,差异有统计学意义(P＜0.05).[结论]微核细胞在两患者组的舌苔脱落细胞内反应强度及出现频率较高,提示有较多的分裂畸变细胞;而P53的表达与微核细胞的出现有关,两者可能代表了证候发展不同的过程.     

Earthworm biomarker responses on exposure to commercial cypermethrin

Cypermethrin is a synthetic pyrethroid insecticide used worldwide in agriculture, home pest control, disease vector control, and food safety. It accumulates in soil. Therefore, traces of cypermethrin may frequently appear in vegetables grown in contaminated soil. There is a push now to develop biomarkers as early warning indicators of environmental pollution. In this study, DNA damage (tail DNA%, tail length, and olive tail moment), the micronucleus, neutral red retention (NRR) time, and pinocytic adherence ability of coelomocytes were investigated in Pheretima peguana earthworms exposed to cypermethrin in filter paper tests. The NRR time of earthworm coelomocytes decreased significantly at a concentration of 3.5 × 10^?3 µg · cm^?2 (1/100 LC₅₀) after 48 h exposure, with a highly negative correlation with cypermethrin concentration. Pinocytic adherence ability of coelomocytes also declined significantly at a cypermethrin concentration of 3.5 × 10^?2 µg · cm^?2 (1/10 LC₅₀). The DNA damage to earthworm coelomocytes (tail DNA%, tail length, and olive tail moment) increased considerably at the highest concentration (3.5 × 10^?1 µg · cm^?2) although the correlation between tail DNA% and cypermethrin concentration was low. Thus, physiological biomarkers were more sensitive than the genotoxic effects in earthworms exposed to commercial cypermethrin. Although a suite of earthworm biomarkers could be used to evaluate cypermethrin terrestrial pollution, the NRR test is easier to conduct and a more sensitive indicator. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 597–606, 2015.     

应用微核实验和彗星电泳实验评价氯化镧90d喂养对小鼠遗传毒性作用

[目的]应用微核实验和彗星电泳实验评价氯化镧亚慢性染毒致小鼠遗传毒性作用. [方法]将100只SPF级ICR小鼠随机分为5组:4个氯化镧染毒组和1个对照组,每组20只,雌雄各半.5个剂量组分别以灌胃的方式给予不同浓度的氯化镧溶液(0、10、20、50和100 mg/kg).每周染毒6次,连续染毒13周后,取小鼠外周血进行彗星实验及镧含量的测定,取小鼠骨髓观察骨髓细胞微核率. [结果]镧染毒剂量达50 mg/kg时,彗星细胞的尾长及尾部DNA含量与对照组相比,差异有统计学意义(P＜0.05),小鼠骨髓细胞微核率与对照组相比,差异有统计学意义(P＜0.05).4个氯化镧染毒组血液中均有不同程度的镧的蓄积,与对照组相比,差异均有统计学意义(P＜0.05). [结论]稀土镧元素可以在血液中蓄积,具有一定的遗传毒性.     

Wentilactone A的遗传毒性评价

目的 检测Wentilactone A的遗传毒性。方法 应用经典遗传毒性检测组合(Ames试验、体外培养CHO细胞染色体畸变试验和小鼠骨髓微核试验)检测Wentilactone A的遗传毒性。结果 Ames试验结果提示,Wentilactone A在每皿5 000、500、50、5、0.5 μg 5个剂量下,在加和不加代谢活化系统（S9）时,对鼠伤寒沙门菌均无致突变性。CHO细胞染色体畸变试验结果提示,在终浓度23.74、47.48、94.96 μg/ml 3个剂量组,在加和不加S9中,于作用4 h和24 h的条件下培养的CHO细胞,均未诱发染色体畸变。小鼠骨髓微核试验在100、200、400 mg/kg 3个剂量下作用24 h以及400 mg/kg剂量下作用48 h对骨髓细胞的微核诱发率,与溶剂对照组比较均无显著差异（P>0.05）。结论 Wentilactone A对鼠伤寒沙门菌无致突变性,对CHO细胞的染色体无致畸变作用,对ICR小鼠无诱发骨髓细胞微核的效应。上述结果提示Wentilactone A不具有遗传毒性和潜在致癌性。     

鸡蛋花提取物的抗突变活性研究

目的 探讨鸡蛋花提取物是否具有抗突变活性,为其开发应用提供实验依据.方法 采用高内涵体外微核实验和Ames实验,计数微核细胞数、回复突变菌落数,计算微核细胞率、相对菌落数及其抑制率;评价不同浓度的鸡蛋花提取物的抗突变效应.结果 高内涵体外微核实验中鸡蛋花提取物20、10mg/mL 2个剂量预处理致突变剂条件下的微核细胞率与致突变剂对照组比较差异有统计学意义(P＜0.01);鸡蛋花提取物与致突变剂同时加入条件下未观察到抗突变效应.Ames实验中鸡蛋花提取物预处理致突变剂条件下对TA98、TA100的相对回变菌落数与致突变剂对照组比较差异有统计学意义(P＜0.01或P＜0.05),且呈一定的剂量-反应关系;同时加入条件下只在25 mg/皿剂量组呈现出对致突变剂的抑制作用.结论 本实验条件下,鸡蛋花提取物能够直接灭活致突变剂,具有一定的拮抗突变的作用.     

In vitro genotoxic and cytotoxic effects of doxepin and escitalopram on human peripheral lymphocytes

Antidepressants are drugs used for the treatment of many psychiatric conditions including depression. There are findings suggesting that these drugs might have genotoxic, carcinogenic, and/or mutagenic effects. Therefore, the present in vitro study is intended to investigate potential genotoxic and cytotoxic effects of the antidepressants escitalopram (selective serotonin reuptake inhibitor) and doxepin (Tricyclic antidepressant) on human peripheral lymphocytes cytokinesis-block micronucleus (CBMN), sister chromatid exchange (SCE), and single cell gel electrophoresis (alkaline comet assay) were used for the purpose of the study. In the study, four different concentrations of both drugs (1, 2.5, 5, and 10?µg/mL) were administered to human peripheral lymphocytes for 24?h. The tested concentrations of both drugs were found to exhibit no cytotoxic and mitotic inhibitory effects. SCE increase caused by 5 and 10?µg/mL of escitalopram was found statistically significant, while no statistically significant increase was observed in DNA damage and micronucleus (MN) formation. Moreover, the increase caused by doxepin in MN formation was not found statistically significant. Besides, 10?µg/mL of doxepin was demonstrated to significantly increase arbitrary unit and SCE formation. These findings suggest that the investigated concentrations of escitalopram and doxepin were non-cytotoxic but potentially genotoxic at higher concentrations.