Genotoxicity and mutagenicity of electronic waste leachates using animal bioassays

Human exposure to electronic waste (e-waste) is increasing, especially in developing nations. This has potential short and chronic adverse health risks. Information is currently scarce on potential genotoxicity of e-waste leachate. In this study, the potential mutagenic and genotoxic effects of leachates from e-waste dumpsites at two electronic markets in Lagos, Nigeria, were investigated. The assays utilized were: bone marrow micronucleus (MN) and chromosome aberration (CA), spermatogonia CA, sperm morphology, and sperm count in mice. Experiments were carried out at concentrations of 1%, 5%, 10%, 25%, and 50% (v/v; leachate: distilled water) of leachate samples. MN analysis showed a concentration-dependent induction of micronucleated polychromatic erythrocytes (MNPCE) across the treatment groups. In the CA tests (bone marrow and spermatogonia), there was concentration-dependent significant reduction in mitotic index and induction of different types of CA. Assessment of sperm shape showed a significant increase in sperm abnormalities with significant decrease in mean sperm count in treated groups. Heavy metals analyzed in the tested samples are believed to contribute significantly to the observed genetic damage. This indicates that e-waste contains potential genotoxic agents; and constitutes a genetic risk in exposed human population.     

Assessment of micronuclei and chromosomal anomalies of five biocompatible materials in mice

In vivo genetic toxicology tests measure direct DNA damage or the formation of gene or chromosomal mutations, and are used to predict mutagenic and carcinogenic potential of compounds for regulatory purposes. These adverse genotoxic effects may be manifested in the form of gene mutations, structural chromosomal aberrations (CA), recombination, and numerical changes. The present investigation was carried to assess genotoxic effects of five different implantable biomaterials developed in different laborataries of Sree Chitra Tirunal Institute of Medical Sciences and Technology. All biomaterials were developed for clinical applications. CA and micronuclei (MN) studies are biomarkers of genotoxicity testing. Leachants from the extract of biomaterials are capable of inducing structural and numerical chromosomal changes. The studies were conducted in Swiss albino mice with the physiological saline extract of materials together with cyclophosphamide and physiological saline as positive and negative controls. Animals were administered intraperitoneally (ip) with a single injection of test, positive (cyclophosphamide), and negative (physiological saline) control and sacrificed after 24 or 48?h. Bone marrow cells were collected for CA and MN assays. Data showed that all five biomaterials did not significantly exert genotoxic effects. Hence, the study indicates that these biomaterials do not induce any chromosomal anomalies.     

In vitro genotoxicity of extracellular extract from Nostoc piscinale

The extracellular extract obtained from 3 weeks incubation of the soil isolate cyanobacterium strain Nostoc piscinale GT-319 in BG-11 broth medium showed cytotoxic activity against Chinese Hamster Ovary (CHO) cells. Based on comet assay, a concentration of 333 µg mL^?1 (IC₅₀) produced DNA breakages in CHO cells. The concentration of 481 mg kg^?1 (LD₅₀) produced acute toxicity in mice at 48 h.     

室内空气高浓度苯系物的蚕豆根尖遗传毒性研究

蚕豆根尖微核(micronucleus,MCN)检测技术是一项检测水环境致突性因素的成熟技术,该研究采用敏感的松滋青皮蚕豆为材料,在密闭容器中模拟室内空气的高浓度苯系物污染,对蚕豆根尖进行染毒,然后用显微镜观察蚕豆根尖细胞中的微核.通过对实验结果进行污染指数(PI)和t检验分析表明:在所有实验浓度下,苯、甲苯和二甲苯都对蚕豆根尖细胞产生了遗传毒害效应;对受试物质量浓度和微核率进行一元线性回归分析后得到线性方程,表明二者间存在线性关系.该实验结果还表明,利用蚕豆根尖微核检测技术检测室内空气中较高浓度的苯系物污染是完全可行的.      

取代苯对人体细胞的定量结构—遗传毒性研究

通过微核实验,测定了 36 种取代苯类化合物对人体外周血淋巴细胞的遗传毒性;并构建了遗传毒性与分子结构参数之间的 QSAR 模型.结果表明,有 34 种化合物显著地导致了微核的产生,具有明显的遗传毒性;遗传毒性的大小与分子结构描述符辛醇-水分配系数(MlogP)、x 轴主惯性矩(Principalx)、γ 极化率[Polar(γ)]等存在良好的结构-活性相关关系,所建模型的相关系数 R² =0.718,具有较高的预测能力,可用来预测取代苯类化合物的遗传毒性.     

气态甲醛对人体颊黏膜细胞遗传毒性的研究

气态甲醛;遗传毒性;人体颊黏膜细胞;彗星实验;体外实验     

敌百虫致小鼠外周血淋巴细胞DNA-蛋白质交联作用研究

为探讨敌百虫致DNA-蛋白质交联作用,以昆明小鼠为受试动物,敌百虫按0、20、40、60 mg·kg-14个剂量水平,灌胃染毒小鼠2周。第5组以提取的正常小鼠外周血淋巴细胞经50μmol·L-1的H2O2处理为阳性对照组。采用经改进的彗星试验方法来检测染毒后外周血淋巴细胞DNA-蛋白质交联效应。结果表明,与空白组相比,各敌百虫染毒组都能引起DNA损伤作用(P0.01)并引起一定程度的DNA-蛋白质交联效应,在较高浓度(40、60 mg·kg-1)时DNA-蛋白质交联尤为明显,存在一定的潜在突变风险。     

Protective effect of Spirulina platensis against aluminium-induced nephrotoxicity and DNA damage in rats

The protective effect of Spirulina platensis (SP) powder against aluminium-induced nephrotoxicity and DNA damage in rats was studied. Male rats receiving daily 40 mg/kg b.wt. aluminium chloride (AlCl₃) orally had increased serum levels of urea and creatinine, up regulated kidney injury molecule-1 and tissue inhibitor of metalloproteinase-1 genes, down regulated catalase and glutathione peroxidase genes, and increased all parameters of kidney DNA damage using comet assay. Treatment with SP alleviated all AlCl₃-induced effects of toxicity, especially when the animals were pre-treated.     

离子液体氯化1-辛基-3-甲基咪唑对洋葱的遗传毒性作用

为探讨咪唑类离子液体氯化1-辛基-3-甲基咪唑([C_8mim][C1])对洋葱的遗传毒性,用浓度分别为2.5、5、10和20mmol·L~(-1)的[C_8mim][C1]处理洋葱内表皮细胞和洋葱根尖8 h,用浓度为10 mmol·L~(-1)的[C_8mim][C1]处理洋葱内表皮细胞和洋葱根尖4 h、8 h、12 h和24 h,研究[C_8mim][C1]对洋葱内表皮细胞核的影响和对洋葱根尖有丝分裂指数和染色体畸变的影响。结果显示,与对照组相比,随着[C_8mim][Cl]处理浓度和时间的增加,洋葱内表皮细胞核偏移率明显升高,根尖细胞有丝分裂指数显著降低,染色体畸变现象明显,畸变率升高。研究表明,当浓度达到2.5 mmol·L~(-1)时,[C_8mim][Cl]对洋葱具有遗传毒性。     

Cytotoxicity and genotoxicity evaluation of urban surface waters using freshwater luminescent bacteria Vibrio-qinghaiensis sp.-Q67 and Vicia faba root tip

The freshwater luminescent bacteria Vibrio-qinghaiensis sp.-Q67 test and the Vicia faba root tip test associated with solid-phase extraction were applied for cytotoxicity and genotoxicity assessment of organic substances in three rivers, two lakes and effluent flows from two wastewater treatment plants (WWTPs) in Xi'an, China. Although the most seriously polluted river with high chemical oxygen demand (COD) and total organic carbon (TOC) showed high cytotoxicity (expressed as TII₅₀, the toxicity impact index) and genotoxicity (expressed as RMCN, the relative frequency of micronucleus), no correlative relation was found between the ecotoxicity and organic content of the water samples. However, there was a linear correlative relation between TII₅₀ and RMCN for most water samples except that from the Zaohe River, which receives discharge from WWTP and untreated industrial wastewaters. The ecotoxicity of the organic toxicants in the Chanhe River and Zaohe River indicated that cytotoxic and genotoxic effects were related to the pollutant source. The TII₅₀ and RMCN were also found to correlate roughly to the dissolved oxygen concentration of the water. Sufficient dissolved oxygen in surface water is thus proved to be an indicator of a healthy water environmental condition.