An Improved Chemical Substitute for Fetal Calf Serum for the Micronucleus Test

The routine use of the micronucleus test in the mutagenicity evaluation of xe-nobiotics is limited by high cost and limited availability of fetal calf serum. On the other hand, there are disadvantages, such as hypotonic damage and clumping of cells, associated with the use of mineral medium substitutes for fetal calf serum. Alternatively, we recommend a chemical medium containing Hanks' buffered salt solution, 1% (w/v) bovine serum albumin, and 0.15% (w/v) ethylenediaminetetraacetic acid, final pH 7.4, to preserve morphology, density and homogeneity of bone marrow cells. Mast cell granules are efficiently removed from rat bone marrow preparations by washing twice with this medium. The morphological preservation of cells is further enhanced by fixation with 70 % (v/v) ethanol for 5 min. The proposed medium provides a cost-effective and convenient substitute for fetal calf serum with substantially improved quality of bone marrow preparations for the micronucleus test.     

Determination of genotoxic and antigenotoxic effects of wild-grown Reishi mushroom (Ganoderma lucidum) using the hen’s egg test for analysis of micronucleus induction

ABSTRACT

The micronucleus (MN) technique is commonly used for genotoxicity testing. The hen’s egg test (HET) for analysis of MN induction (HET-MN) is an inexpensive, rapid and simple genotoxicity assay that is compatible with animal protection and ethical considerations. Ganoderma lucidum (Curtis) P. Karst is known also as reishi mushroom and mushroom of immortality. It has long been used to treat disorders including fungal infections, influenza, common cold, hepatitis, diabetes, high cholesterol and cancer in many countries including China and Japan. G. lucidum strengthens the immune system and reduces the side effects of chemo- and radiotherapy. We investigated the possible genotoxic and antigenotoxic effects of the aqueous extract of wild-grown G. lucidum from Turkey using the HET-MN test. Three different doses of aqueous extract of G. lucidum, 50 µg/egg vitamin C as an antigenotoxic agent and 50 µg/egg cyclophosphamide as a genotoxic compound were injected separately or together into fertilized chicken eggs at incubation day 8. Embryonic peripheral blood smears were prepared and stained with a modified May-Grünwald-Giemsa method on incubation day 11. The frequencies of MN and nuclear abnormalities in erythrocytes were determined using light microscopy. Although the aqueous extract G. lucidum exhibited no genotoxic effect, it did exhibit an antigenotoxic effect. Our findings suggest that G. lucidum extract is a valuable natural antigenotoxic agent.     

Evaluation of genotoxicity using the micronucleus assay and nuclear abnormalities in the tropical sea fish Bathygobius soporator (Valenciennes, 1837) (Teleostei, Gobiidae)

The micronucleus and nuclear abnormalities assays have been used increasingly to evaluate genotoxicity of many compounds in polluted aquatic ecossystems. The aim of this study is to verify the efficiency of the micronucleus assay and nuclear abnormality assay in field and laboratory work, when using erythrocytes of the tropical marine fish Bathygobius soporator as genotoxicity biomarkers. Gill peripheral blood samples were obtained from specimens of Bathygobius soporator. In order to investigate the frequencies of micronuclei and to assess the sensitivity of species, the results were compared with samples taken at the reference site and maintained in the laboratory, and fish treated with cyclophosphamide. The micronucleus assay was efficient in demonstrating field pollution and reproducing results in the labotatory. There were significant higher frequencies of micronuclei in two sites subject to discharge of urban and industrial effluents. The nuclear abnormality assay did not appear to be an efficient tool for genotoxicity evaluation when compared with field samples taken at a reference site in laboratory, with a positive control.     

Toxicity and genotoxicity of wastewater from gasoline stations

The toxicity and genotoxicity of wastewater from eight gasoline stations in Brasília, Brazil's capital city, was studied by assessing chromosomal aberrations, chromosomal malsegregation and the mitotic index in Alliumcepa root cells, and the occurrence of micronucleus and nuclear abnormalities in peripheral erythrocytes of tilapia fish (Oreochromis niloticus). The content of gasoline station effluents was also analyzed based on several physico-chemical parameters. None of the wastewater samples was genotoxic to A. cepa root cells, although cell proliferation was significantly inhibited, especially at the highest concentrations. Likewise, no micronuclei were observed in O. niloticus peripheral erythrocytes, even after exposure to high concentrations, but there was an increase in the number of nuclear abnormalities and fish mortality. These results show that although the effluent from gasoline stations is processed by an oil/water separation system before being discharged into the main sewage system, the wastewater still contains toxic compounds.     

Protective effect of Hemidesmus indicus R.Br. root extract against cisplatin-induced cytogenetic damage in mouse bone marrow cells

The aqueous extract of Hemidesmus indicus roots was investigated for its in vivo antigenotoxic effect against cisplatin-induced cytogenetic damage. Swiss albino mice were administered with various doses of the extract either singly (50, 100 and 200 mg/kg body weight) or as split doses (10, 20 and 40 mg/kg bw/day) for five consecutive days by oral gavage. As endpoints, chromosome aberrations, micronuclei in polychromatic erythrocytes, mitotic index and PCE/NCE ratio were estimated. The extract protected the bone marrow cells from cisplatin-induced genotoxicity in an inverse dose-dependent manner. However, the extract was cytotoxic at all doses. But, under split dose regime it conferred a higher level of genoprotection and was not cytotoxic at the lower two doses. The presence of saponins, tannins, phenols, terpenoids, flavonoids and coumarins in the crude extract could explain these effects.     

Mucocytes with micronuclei and sowing with the coccoid forms of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in a mucous membrane of human stomach

In accordance with the solution of IARC, the Helicobacter pylori (H. pylori) refers to carcinogens of the first group. As the carcinogenic factors have a mutagen effect, we have undertaken the cytogenetic testing of 62 patients with chronic nonatrophic gastritis (40 of which have H. pylori-associated gastritis) by account of the micronuclei in mucocytes of tectorial-pit epithelium of the mucous membrane of the antral region of the stomach. The detection of H. pylori cells in the mucous membrane of the stomach (SMM) was performed with the help of immunocytochemical method that permitted us to visualize both the bacillar and coccoid forms, as well as to evaluate the degree of sowing of SMM with the coccoid forms of H. pylori. In the patient group with H. pylori-associated gastritis, the frequency rate of mucocytes with micronuclei in SMM appears to be considerably higher than in the group of patients whose SMM was not infected with H. pylori (P < 0,05). A high scale of sowing with the coccoid forms of H. pylori was accompanied by a significantly heightened level of mucocytes with micronuclei in the SMM. In connection with this and on the basis of modern notions of carcinogenesis, based on mutagen modifications in somatic cells, patients that exhibit high sowing with coccoid forms of H. pylori may be placed in the group of heightened oncologic hazards.     

应用蝌蚪快速检测环境变异的两种方法--微核试验和单细胞凝胶电泳

本文介绍了应用无尾两栖类动物的蝌蚪进行环境监测的两种方法——微核试验和单细胞凝胶电泳。此两种环境检测的方法与其他环境检测方法相比具有快速,简便,易操作,适于检测现场应用,可大面积推广等优点。     

稀土与铜对鲹鲦鱼红细胞微核及核异常的影响

研究了稀土元素镧与铜离子单独或联合作用时,对鲹鲦红细胞微核及核异常的影响。结果表明:处理24h,0.01～0.5mg/L的La3 能显著降低红细胞微核及核异常的发生,不具遗传毒性.但当浓度为1～50mg/L时则能诱发红细胞微核及核异常的发生,与对照组相比,相差显著或极显著(P<0.05或P<0.01),具较强的遗传毒性;铜能显著诱导红细胞微核及核异常的发生;联合作用时,微核率及核异常率明显低于Cu2 而高于La3 单独作用时的微核率和核异常率,提示一定浓度的稀土元素能减轻其他重金属元素引起的遗传毒性。     

SO2衍生物诱发蚕豆根尖细胞微核和后期异常的研究

研究SO₂体内衍生物--亚硫酸钠和亚硫酸氢钠混合液(3:1 mmol·L^-1/mmol·L^-1)诱发蚕豆根尖细胞微核和后期异常的效应。结果表明:SO₂衍生物处理可诱发蚕豆根尖间期细胞微核和核芽,使分裂后期出现多种染色体异常,如断片、桥以及滞后染色体等。异常细胞中以微核细胞和染色体断裂细胞居多。在一定浓度范围内,细胞异常率与处理液浓度之间表现正的线性相关。这些研究结果表明,蚕豆根尖间期微核和后期染色体异常有可能用作检测SO₂污染的生物剂量计。     

牡蒿提取物抗氧化作用和遗传毒性研究

本文旨在研究牡蒿提取物(Artemisia japonica Extract,AJE)对小鼠抗氧化作用和遗传毒性效果。在建立卡介苗(BCG)+脂多糖(LPS)诱导免疫性肝损伤小鼠模型的基础上,采用给小鼠灌胃不同浓度的AJE后,分别测定小鼠肝组织中丙二醛(MDA)、谷胱甘肽氧化酶(GSH-Px)和超氧化歧化酶(SOD)的活性。检查小鼠骨髓嗜多染红细胞微核率和小鼠精子畸形率。结果表明,在一定剂量范围内,牡蒿提取物有降低小鼠肝组织中MDA含量、升高GSH-Px和SOD活性的作用,微核试验和精子畸形试验结果均为阴性。说明AJE具有较强的抗氧化作用,无遗传毒性。