绿茶对微囊藻毒素LR诱导肝细胞凋亡、Bcl-2表达及骨髓嗜多染红细胞微核的影响

背景与目的:研究绿茶(green tea,GT)对微囊藻毒素LR(MC-LR)诱导肝细胞凋亡、Bcl-2蛋白表达及微核发生的影响以探讨毒性拮抗机制.材料与方法:雄性小鼠50只随机分为5组,分别为空白对照、MC-LR染毒组、GT高低剂量拮抗组和环磷酰胺对照组.实验第1 d起GT高、低剂量拮抗组小鼠每日分别给予12 g/L和2 g/L两种浓度的GT自由饮用,连续18 d.自第6 d开始,染毒小鼠每日给予MC-LR 10 μg/kg腹腔注射1次,空白对照给予DMSO腹腔注射,连续13 d.环磷酰胺对照组以50 mg/kg剂量间隔24 h两次给药后6 h取材.小鼠处死后采用免疫组化和计数法对肝细胞凋亡、Bcl-2蛋白表达以及骨髓嗜多染红细胞(PCEs)微核发生率进行检测和分析.结果:(1)MC-LR染毒明显诱导小鼠肝细胞凋亡增加.高剂量GT处理后明显抑制MC-LR染毒所致小鼠肝细胞凋亡的发生(P＜0.05);(2)单纯MC-LR染毒肝细胞Bcl-2表达未见明显变化,GT各剂量组小鼠肝脏Bcl-2的表达明显增加,与MC-LR染毒组相比差异具有统计学意义(P＜0.01).(3)GT拮抗组小鼠骨髓嗜多染红细胞微核率(PCEs-MN)与MC-LR染毒对照和空白对照相比,其差异均无统计学意义(P＞0.05).结论:GT能上调抑癌基因Bcl-2的表达,抑制细胞凋亡.MC-LR染毒及GT拮抗对微核发生均未有显著影响.     

鼎力健胶囊的安全性试验

背景与目的:鼎力健胶囊是由蚂蚁粉与中药组成的复方制剂,为确定其对人体健康是否会造成损害,对其进行食品安全性毒理学评价.材料与方法:用急性毒性试验、小鼠骨髓细胞微核试验、小鼠精子畸形试验和Ames试验方法对鼎力健胶囊的急性毒性和遗传毒性进行研究.结果:急性毒性试验大鼠、小鼠最大耐受剂量(maximum tolerated-dose,MTD)均＞20.0 g/kg体重,属无毒级物质;Ames试验、小鼠骨髓细胞微核试验和小鼠睾丸精子畸形试验结果均为阴性.结论:鼎力健胶囊无急性毒性和致突变性.     

Anti-clastogenic effect of magnolol on benzo(a)pyrene-induced clastogenicity in mice.

It was previously reported that magnolol strongly inhibited the mutagenicity induced by the indirect mutagens [benzo(a)pyrene (B(a)P), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-aminodipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2), 2-aminoanthracene (2AA), and 7,12-dimethylbenz[a]anthracene (DMBA)] in Salmonella typhimurium TA98 and TA100 in the Ames test, and that the mechanism of this anti-mutagenic effect may involve the inhibition of the metabolic activation of indirect mutagen enzymes. In this study, the in vivo anti-clastogenic effect of magnolol against clastogenicity induced by B(a)P was evaluated using the micronucleus test in mice. Animals were treated with an oral administration of magnolol (1, 10, and 100 mg/kg) at -24, 0, 24, 48, 72, and 96 h before a single intraperitoneal injection of B(a)P. Peripheral blood specimens were prepared 48 h after administration of B(a)P, and analyzed by the acridine orange (AO) technique. The results indicated that magnolol inhibited clastogenicity induced by B(a)P at various administration times. In order to elucidate the mechanism behind this effect, we measured the activity of the detoxifying enzymes [UDP-glucuronosyltransferase (UGT) and glutathione-S-transferase (GST)] and antioxidative enzymes [superoxide dismutase (SOD) and catalase] in the liver when treated with an oral administration of magnolol at various administration times. Its effect on clastogenicity created by exposure to oxidative DNA damage-inducing X-ray irradiation was also evaluated using the micronucleus test in mice. Results showed that magnolol increased the activity of both UGT and SOD enzymes, and also inhibited the clastogenicity induced by X-ray irradiation. Magnolol had an anti-clastogenic effect on B(a)P in the micronucleus test as well as an anti-mutagenic effect on indirect mutagens in the Ames test. The anti-clastogenic effect of magnolol was also suggested by the increases in UGT and SOD enzyme activity, and by the attenuation of oxidative damage induced by X-ray irradiation.     

Flow cytometric analysis of micronuclei in peripheral blood reticulocytes III. An efficient method of monitoring chromosomal damage in the beagle dog.

Erythrocyte-based micronucleus tests have traditionally analyzed bone marrow because splenic filtration in most species removes micronucleated cells from peripheral blood. We have evaluated a flow cytometric method for monitoring micronucleated reticulocyte frequencies (%MN-RET) in the peripheral blood of beagle dogs treated with cyclophosphamide (CP) and have found that analysis of micronucleated reticulocytes (MN-RETs) in peripheral blood is a suitable surrogate for bone marrow analysis. The three-color flow cytometric method uses anti-CD71 labeling to identify reticulocytes and Plasmodium berghei-containing erythrocytes as a calibration standard. The spontaneous %MN-RET determined by flow cytometry was 0.31 +/- 0.09% (n = 22) for peripheral blood, compared with 0.38 +/- 0.13% (SD, n = 12) for bone marrow, and 0.27 +/- 0.08% (n = 12) for peripheral blood by microscopic scoring with acridine orange staining. The kinetics of appearance and disappearance of MN-RETs in blood were determined by collecting daily samples after iv treatment with CP. The maximum frequency occurred approximately 48 h after dosing. Frequencies of MN-RETs in peripheral blood at steady state following daily CP treatment were 55-68% of corresponding bone marrow values assessed by microscopy and 55-112% as assessed by flow cytometry. This difference is presumably due to splenic removal, which appears slightly less stringent than that previously reported for CP-treated Sprague-Dawley rats. Responses in bone marrow and peripheral blood were highly correlated and similar to or greater than those reported in mice and rats at equitoxic doses.     

Genotoxicity testing of aqueous extracts of Mahwangyounpae-tang, a polyherbal formula

Mahwangyounpae-tang (MT), consisting of 22 types of herbal extracts has been used for thousands of years in Korean traditional medicine for the oral treatment of respiratory diseases including asthma. As part of a safety evaluation of MT extracts for use in asthma, the potential genotoxicity of an aqueous MT extract was evaluated using the standard battery of tests (bacterial reverse mutation assay; chromosomal aberrations assay; mouse micronucleus assay) recommended by Korea Food and Drug Administration (KFDA). The MT extract was determined not to be genotoxic under the conditions of the reverse mutation assay, chromosomal aberrations assay and mouse micronucleus assay. Use of MT is presently expected to be safe, as anticipated intake is small compared to the doses administered in the genotoxicity assays and may, after further toxicity research, prove to be a useful anti-asthma agent.     

多环芳烃致4种细胞彗星尾矩和双核细胞微核率变化差异的研究

目的探讨彗星尾矩和双核细胞微核(CBMN)率两个指标对多环芳烃反应动力学的差异。方法应用4株细胞系,分别是中国仓鼠卵巢细胞CHO-K1、小鼠成纤维细胞NIH3T3、中国仓鼠肺成纤维细胞CHL、人胚肺成纤维细胞HELF,给予不同浓度的苯并(a)芘[B(a)P]处理,观察彗星尾矩和CBMN率的变化情况。阳性对照分别是过氧化氢和环磷酰胺。结果在所应用的B(a)P浓度范围内,4种细胞均在较低剂量下就出现了明显的拖尾(CHO-K1:0.5μmol/L;NIH3T3:0.75μmol/L;CHL:0.5μmol/L;HELF:0.3125μmol/L),并且随作用浓度的增加,彗星尾矩呈直线形上升趋势,各组与其邻近的较低剂量组相比,差异有显著性。CBMN率在中剂量组才出现显著升高(CHO-K1:2.0μmol/L;NIH3T3:1.5μmol/L;CHL:2.0μmol/L;HELF:1.25μmol/L),达到一定作用剂量后,CBMN率的上升趋于平缓,其剂量反应曲线基本呈S型。结论彗星尾矩和CBMN率对多环芳烃动力学反应模式不同,敏感性不同,在进行环境致癌物早期效应标志物研究时,应合理地将两种方法相结合,综合评价化学物所致遗传损伤。     

氯乙烯暴露对作业工人染色体的损伤

目的 探讨在我国目前职业卫生标准条件下,接触氯乙烯(VCM)能否对作业工人染色体造成损伤. 方法 选择上海某化工厂205名VCM作业工人为接触组,并以41名不接触VCM的健康志愿者为对照组;胞质分裂阻滞微核试验分析两组工人外周血淋巴细胞微核率.因素分析采用广义线性模型中的Poisson回归分析. 结果 VCM接触组工人和对照组人群外周血淋巴细胞微核率分别为(3.58±2.33)‰和(1.22±1.19)‰.Poisson回归分析VCM暴露与微核率之间的关系,最后进入方程的变量为VCM暴露、性别和年龄.在控制潜在的混杂因素如性别、年龄、吸烟和饮酒后VCM暴露的校正FR值及95%CI为3.104 3(2.352 3,4.194 6).以男性作为参比,女性FR值为1.182 3,95%CI为(1.024 9,1.362 5).年龄作为连续变量FR值为1.016 4,95%CI为(1.006 4,1.026 4). 结论 在当前我国职业卫生标准情况下,VCM暴露仍能够对作业工人遗传物质造成损害.     

抗着丝点抗体在鉴别微核起源上的应用

以抗着丝点抗体间接免疫荧光染色法（ＣＲＥＳＴ染色法）分析了纺锤体毒剂秋水仙素、有丝分裂抑制剂对苯二酚及多功能烷化剂丝裂霉素Ｃ诱发小鼠骨髓细胞微核的起源。结果指出，３种受试物均显著诱发小鼠骨髓嗜多染红细胞微核发生。秋水仙素诱发微核中，７１％含有着丝点，表现ＣＲＥＳＴ阳性，提示这些微核由完整落后染色体形成。对苯二酚诱发微核中，１９％为ＣＲＥＳＴ阳性，与对照无显著差异，说明其遗传毒性主要体现为染色体诱裂效应，丝裂霉素Ｃ在所有受试物中微核诱发率居首，但ＣＲＥＳＴ阳性率仅６％，显著低于对照，暗示该化合物具强烈的染色体诱裂效应，且诱裂部位可多集中在着丝粒处，使诱发微核内均无完整的着丝点功能结构，表现ＣＲＥＳＴ阴性，ＣＲＥＳＴ染色法能够为鉴别哺乳动物非整倍体诱发剂提供依据。     

人参茎叶总皂甙对遗传物质损伤的修复作用及其时间效应

本研究通过微核试验证明：给小鼠腹腔注射丝裂霉素Ｃ（ＭＭＣ）后，再给予人参茎叶总皂甙（ｇｉｎｅｓｅｎｏｓｉｄｅｓＧＮＳｉ．ｇｏｒｉ．Ｐ），可明显降低０．５、１．００ｍｇ／ｋｇＭＭＣ诱发的小鼠骨髓细胞微核率；时间效应试验证明；在诱变剂作用前，给予小鼠ＧＮＳ，降低微核细胞率效果更好，以作用４８ｈ效果最佳。     

DDNAQ致突变作用的研究

本研究对某厂１２２名接触１─〔２．４─二硝基〕苯氧基—５—〔３．４—二硝基〕苯氧基—４．８—二硝基蒽醌（ＤＤＮＡＱ）（车间空气粉尘浓度为０．１６ｍｇ／ｍ３）的工人和某厂１００名非接触工人进行了口腔粘膜上皮细胞微核检查，发现接触组微核人员出现率和平均微核率分别为７６．２２％和２％，显著高于非接触组相应的３０．００％（Ｐ＜０．０１）和０．４％（Ｐ＜０．０１）。是时，上述接触组和非接触组各１２名工人进行了中性白细胞ＤＮＡ含量测定，接触组（６００个细胞）ＤＮＡ含量为３．６７±０．３０，与非接触组（６００个细胞）的３．０２±０．１８相比较，差别显著（Ｐ＜０．０１）。此外，动物实验结果表明，小鼠受精卵染色体数目畸变细胞率，染毒组（０．８ｍｇ／ｋｇ·ｗｔ）为１８．７５％，显著高于对照组的８．７４％（Ｐ＜０．０５）；金黄地鼠胚胎早期培养细胞转化试验，染毒组（０．１ｕｇ／ｍｌ，１．０ｕｇ／ｍｌ转化克隆／总克隆为４／４６７、３／４４２（空白对照组为０／５０８），呈阳性结果。上述结果说明ＤＤＮＡＱ对遗传物质存在作用，应加强职业性接触工人卫生防护工作，保护工人及其后代的健康。