锌对染汞孕鼠胚胎毒性的影响及其机理研究

目的:探讨妊娠期补锌对染汞孕鼠胚胎发育毒性的保护作用.方法:建立孕鼠动物模型,应用不同剂量的氯化甲基汞(0.01、0.05、2.00mg/kg·d)及5.00mg/kg·d硫酸锌于妊娠6～9天连续灌胃.蒸馏水灌胃为对照组,观察孕鼠及胚胎的汞毒性及硫酸锌的影响.应用ICP-MS法测定各组胎鼠脑组织汞含量;Western blot法检测各组胎鼠脑bcl-2蛋白表达情况;TUNEL法检测各组胎鼠脑细胞凋亡情况.结果:各组均未发现死胎、吸收胎及畸形胎;0.01、0.05mg/kg·d氯化甲基汞对孕鼠及胎鼠生长发育没有明显的抑制作用;2.00mg/kg·d氯化甲基汞可以明显抑制孕鼠体重增长及胎鼠身长、体重及尾长的增长(P＜0.05),但对孕鼠产仔数、胎窝总重及胎盘总重没有明显的影响,0.05mg/kg·d、2.00mg/kg·d 氯化甲基汞组胎鼠脑组织汞含量较对照组明显升高(P＜0.05),bcl一2蛋白表达明显下降(P＜0.05),脑细胞凋亡较对照组明显升高(P＜0.05);应用硫酸锌预处理后,氯化甲基汞对孕鼠及胚胎的毒性作用明显降低(P＜0.05),胎鼠脑组织汞含量较染汞组明显降低(P＜0.05),bcl-2蛋白表达明显升高(P＜0.05),胎鼠脑细胞凋亡明显降低(P＜0.05).结论:孕期补锌可以降低氯化甲基汞对孕鼠胚胎的毒性作用,其机制与锌通过升高bel-2蛋白的表达而抑制细胞凋亡有关.     

全氟辛烷磺酸盐对胚胎期大鼠雄性生殖系统的影响

目的:研究全氟辛烷磺酸盐(PFOS)对胚胎期大鼠雄性生殖系统发育的影响.方法:PFOS分别以5、10、20 mg· kg-1·d-1灌胃染毒孕12-19天的SD母鼠,染毒结束后,测量雄性胎鼠体重、身长、睾丸重量、AGD;酶联免疫吸附法检测雄性胎鼠睾丸内睾酮水平;实时荧光定量PCR法测睾丸组织类固醇激素合成急性调节蛋白(StAR)、胰岛素样因子3(INSL3)mRNA的相对表达量.结果:与对照组相比,高剂量染毒组雄性胎鼠体重、体长、AGD长度显著降低(P＜0.01),睾丸重量减轻(P＜0.05);高剂量染毒组雄性胎鼠睾丸中内睾酮水平下降(P＜0.05);高剂量染毒组雄性胎鼠睾丸组织中StAR mRNA的表达量降低(P＜0.05),而中剂量染毒组StAR mRNA和INSL3 mRNA表达量则明显升高(P＜0.01).结论:孕期染毒PFOS对雄性胚胎生殖系统的发育有毒性作用,其机制可能与PFOS影响睾酮合成和INSL3 mRNA的表达有关.     

蝉棒束孢子实体的致畸性评价及对高血糖小鼠血糖的影响

对妊娠第7-16天Wistar大鼠连续给予口服蝉棒束孢子实体低、中、高3个剂量（0.85、1.70、3.40g/kg）10d,观察给药组对大鼠孕期体重、死胎率、吸收胎率、活胎数、每窝平均胎仔数、胎鼠重、胎鼠身长、前囟宽度、子宫连胎重及胎鼠外观、内脏发育、骨骼发育的影响,研究妊娠动物接触蝉棒束孢子实体后引起的致畸可能性。对正常小鼠、STZ致高血糖模型小鼠给予口服不同剂量的人工培植蝉棒束孢子实体（0.4、0.25、0.125g/kg）,测定空腹血糖及糖耐量,评价蝉棒束孢子实体的降血糖作用。结果表明：与阴性对照组相比,人工培植蝉棒束孢子实体各剂量组在大鼠孕期体重、死胎率、吸收胎率、胎鼠重、胎鼠身长和前囟宽度、胎鼠外观、内脏和骨骼发育等方面均无显著性差异（P>0.05）;与模型对照组（0g/kg BW）相比,人工培植蝉棒束孢子实体中、低两个剂量组均能降低STZ致高血糖模型小鼠给葡萄糖后0.5h血糖水平（P<0.05）,低剂量组能明显降低高血糖模型小鼠0-2h血糖曲线下面积,且对小鼠体重及正常小鼠空腹血糖均无不良影响。提示人工培植蝉棒束孢子实体对大鼠无明显的母体毒性、胚胎毒性和致畸性;对高血糖小鼠具有降血糖的作用。     

氧氟沙星对小鼠生殖毒性和致畸性的研究

目的研究氧氟沙星对昆明系小鼠胚胎和胎鼠发育的影响,确定其是否存在生殖毒性和致畸性。方法①雄鼠分别灌服各剂量氧氟沙星,连续10d,末次给药24h后与母鼠合笼,在妊娠第三天取胚胎,记录各剂量组胚胎发育率。②孕鼠妊娠零天给药,分别经口灌服高、中、低剂量[36、72和360mg(kg.bw)]氧氟沙星溶液,连续给药3d,在妊娠第三天收集胚胎,记录胚胎发育率。③孕鼠妊娠零天给药,分别经口灌服各剂量氧氟沙星溶液,连续给药10d,在妊娠第16天取出胎鼠,记录胎鼠体重、胎盘重、活胎数、胎鼠外观畸形和内脏畸形等指标。结果给药组与对照组相比,雄鼠服用高剂量组360mg(kg.bw)氧氟沙星对着床前胚胎发育影响显著(P<0.05),而中等剂量和低剂量组对着床前胚胎发育的影响不显著(P>0.05)。雌鼠服用不同剂量氧氟沙星对着床前胚胎发育影响不显著(P>0.05)。氧氟沙星对受孕鼠的活胎数和吸收胎数均无明显影响,给药组的活鼠体重、胎盘重均未见明显差异(P>0.05);药物组和对照组均未出现外观畸形和内脏畸形,也不存在剂量和效应关系。结论孕鼠服用不同剂氧氟沙星对昆明系小鼠胚胎和胎鼠发育无明显的影响,表明氧氟沙星对雌性鼠不具有明显的生殖毒性和致畸性;但雄鼠服用高剂量氧氟沙星对着床前胚胎发育影响显著。     

三聚氰胺对SD孕鼠及胎鼠的毒作用

为阐明三聚氰胺对孕鼠和胎鼠毒性作用,将40只SD孕鼠随机分为高剂量组(Ⅰ)、中剂量组(Ⅱ)、低剂量组(Ⅲ)及空白对照组(Ⅳ),共4组,于妊娠第6~19天,分别经口灌服800 mg/kg·d、200 mg/kg·d、20 mg/kg·d和0 mg/kg·d三聚氰胺混悬液。染毒期间,观察孕鼠中毒表现,以及不同妊娠时间体重变化;于妊娠第20天处死母鼠,检测血清尿素氮、肌酐及尿酸,胎鼠及胎盘重量等指标;观察母鼠和胎儿肾脏、胎盘组织病理变化。结果显示,在染毒期,Ⅰ、Ⅱ组母鼠出现精神差等症状;与Ⅳ组相比,Ⅰ、Ⅱ组母鼠、胎鼠和胎盘重量,血液生化指标有显著或极显著差异(P0.05或P0.01),且Ⅰ、Ⅱ组母鼠、胎鼠肾脏以及胎盘有明显病理变化;但3个剂量水平的三聚氰胺对胚胎的存活无影响,也不产生致畸作用。     

孕期高果糖摄入对胚胎发育和胎盘血管因子的研究

目的：探讨孕期高果糖摄入对胚胎发育的影响及胎盘血管因子对其影响的机制。方法：成年雌性SD大鼠与正常饮食雄性大鼠进行交配,孕鼠随机分为5组,分别是对照组、正常剂量果糖组、高剂量果糖组、高剂量蔗糖组和超高剂量果糖组,在孕期分别给予1mL去离子水、1.6g/kg、4.8g/kg、4.5g/kg和8.0g/kg的果糖水和蔗糖水灌胃,连续干预3w,于第3w末处死孕鼠,麻醉、取血并剖取胎鼠,检查胎鼠的一般状况、着床、死胎、吸收胎、外观畸形等,制作子代内脏和骨骼标本,观察内脏和骨骼的情况;称量胎重和胎盘重,观察各组间胎盘血管内皮生长因子（VEGF）、血管内皮生长因子受体-1（sFlt-1）和一氧化氮（NO）的变化。结果：对孕鼠连续进行3w的果糖干预后,超高剂量果糖组子代出生体重显著低于对照组（P＜0.05）;高剂量果糖组、高剂量蔗糖组和超高剂量果糖组子代与对照组和正常剂量果糖组相比,死胎数和吸收胎数显著增加（P＜0.05）;但各组子代并没有发生骨骼畸形和内脏出血。超高剂量果糖组胎盘重量显著低于对照组（P＜0.05）;高剂量果糖组、高剂量蔗糖组和超高剂量果糖组胎盘中VEGF和NO水平显著低于对照组和正常剂量果糖组（P＜0.05）;胎盘中sFlt-1水平明显高于对照组和正常剂量果糖组（P＜0.05）。结论：孕期高果糖摄入可增加子代发生死胎和吸收胎等不良结局的风险,胎盘中VEGF、NO的水平降低和sFlt-1水平增高可能是导致子代发生不良结局的原因,具体机制值得深入研究。     

蛇毒心脏毒素对动物细胞的遗传损伤和生殖毒性研究

目的 应用眼镜蛇毒心脏毒素（ＣＴＸ）作用于小鼠的骨髓细胞和生殖细胞,以探讨ＣＴＸ对动物体的生殖毒性和遗传毒性。方法 对小鼠腹腔注射不同剂量ＣＴＸ,通过生殖毒性实验和致突变实验,分析孕鼠的胚胎存活率,骨髓细胞和精母细胞的染色体畸变率。结果：ＣＴＸ能影响胎鼠的生长发育,使孕鼠的增重和活胎率均明显地降低（Ｐ〈０．００１）,染色体畸变实验显示ＣＴＸ０．４ｍｇ／ｋｇ剂量上精母细胞多倍体和非整倍体细胞数目增高     

电磁脉冲对孕鼠及其胚胎的影响

目的：探讨电磁脉冲（electromagneticpulses,E脚）对孕期小鼠及其胚胎发育的影响。方法：采用不同场强的EMP（分别为0、50、100、200、400kV·m-1）辐照器官形成期的BALB／c孕鼠,于孕18天解剖小鼠,测量孕鼠体重增长值、脏器／体重,胎盘重、胎鼠体重、身长、尾长,并记录吸收胎、死胎、生长发育迟缓及畸胎的数量。结果：各辐照剂量组孕鼠体重增长值、脏器／体重与对照组相比均无显著性差异（P〉0．05）;胎盘重、胎鼠体重、身长、尾长数值明显低于对照组（P〈O．01）。50、400kV·m-1和100、200、400kV·m-1辐照组可分别导致死胎率和生长发育迟缓率增加（P〈0．05）,在400kV·m-1的EMP辐照组中,畸胎数也有升高的趋势,其中,畸胎主要表现为肢体和骨发育异常。结论：本实验条件下,不同场强的EMP辐照可对器官形成期小鼠胚胎的生长发育产生一定的影响,胚胎肢芽及骨发育可能是EMP作用的特殊靶点。     

SD大鼠胚胎-胎仔发育毒性试验的基础数据

目的 检测胚胎-胎仔发育毒性试验中SD大鼠妊娠期的体重、生殖功能指标及胎鼠的各项发育指标,为SD大鼠的发育毒性研究提供参考数据.方法 395只SD雌性大鼠,交配成功后,于妊娠第20天剖检孕鼠,检查孕鼠的内脏器官有无异常,称量子宫重量、窝重和胎盘重量,计数黄体数、着床数、活胎数、吸收胎数和死胎数.胎鼠共5272只,将一半胎鼠放人固定液中做内脏检查,另一半胎鼠进行骨骼检查,检查胎鼠外观、内脏和骨骼有无异常和变异.结果 和结论 建立SD大鼠胚胎-胎仔发育毒性试验中各项指标的数据库,求得各指标的正常值及标准差,95％的可信区间,为生殖毒性研究提供正常值的参考依据.     

孕期大鼠暴露PFOS对胎鼠肝脏毒性的影响

目的:研究在孕期暴露PFOS对胎鼠的肝脏毒性的影响.方法:将孕期为12天的16只SD雌性大鼠,随机分为4组给予不同剂量的PFOS[0(对照),5,10,20 mg·kg-1],连续灌胃7天,在GD19天时对母鼠和胎鼠的体重、胎鼠肝脏的生化指标、母鼠血清的生化指标进行了相应的检测.结果:与对照组相比,母鼠体重在20 mg·kg-1组显著下降(P＜0.001);胎鼠的体重和体长在20mg·kg-1组显著下降(P＜0.001);胎鼠的肝脏重量降低,呈剂量依赖性,并伴有肝细胞浊肿、变性甚至坏死;10 mg· kg-1组胎鼠肝脏中的酶活性(ALT、AST、GGT和ALP等)显著升高(P＜0.001);母鼠血清的大部分生化指标未发生明显变化.结论:孕期大鼠暴露在PFOS的环境下会严重损伤胎鼠的肝脏功能.     

Microbial Responses to Environmentally Toxic Cadmium

Abstract We analyzed the soil microbial communities from one uncontaminated and two metal-impacted soils and found that while cadmium adversely affected the numbers of culturable bacteria in all soils, cadmium-resistant isolates were found from each of the soils. With exposure to 24 and 48 μg ml^-1 soluble cadmium, the metal-contaminated soil communities were more resistant than the uncontaminated soil community. In addition, in one metal-stressed soil, the resistant population became more resistant with increased cadmium levels. Ribosomal 16S DNA sequencing identified the isolates as Arthrobacter, Bacillus, or Pseudomonas spp. Further characterization demonstrated that two of the isolates were highly resistant to soluble cadmium with maximum resistance at 275 μg ml^-1 cadmium. These isolates were also resistant to a variety of antibiotics, namely ampicillin, gentamicin, penicillin, and streptomycin, but no overall correlation was found between enhanced antibiotic resistance and cadmium resistance. One Pseudomonas isolate H1 did become more resistant with increasing cadmium levels, suggesting a different resistance mechanism at high cadmium concentrations. Received: 29 April 1999; Accepted: 7 July 1999; Online Publication: 30 November 1999     

木槿品种对镉胁迫的生理响应及耐镉能力评价

研究镉胁迫对木槿的生理影响,比较木槿品种的镉耐受能力,为镉污染地区的植物材料选择提供依据.以3个木槿品种为材料,采取盆栽控制试验,测定其生长、生理指标,通过隶属函数分析综合比较品种耐镉能力.木槿的株高与地径增长量、叶绿素A+B与可溶性蛋白含量随胁迫浓度增加呈先上升后降低或逐渐降低趋势,而且随时间延长,降低程度不断加强;...     

Cadmium binding to human alpha 2-macroglobulin

alpha 2-Macroglobulin (alpha 2M) is one of the major cadmium-binding proteins of human plasma. As determined with equilibrium dialysis, alpha 2M bound 4.6 (+/- 0.7) mol Cd2+ per mol protein with an apparent dissociation constant of (9.6 (+/- 5.0] X 10(-7) M. Methylamine-modified alpha 2M (alpha 2M-Me) had a similar affinity for Cd2+ (Kd,app = 5.3 X 10(-7) M), but fewer binding sites. Cadmium produced a small increase in the amidolytic activity of trypsin in the presence of alpha 2M and soybean trypsin inhibitor. Using the binding parameters determined from the equilibrium dialysis studies, the Cd2+ concentration which produced a half-maximal increase in amidolytic activity corresponded to saturation of all Cd2+-binding sites in one-half of the alpha 2M molecules. From these results, a model is proposed in which one Cd2+-binding site is present in each of the four polypeptide chains which compose alpha 2M.     

Compartmentation of Cadmium and Iron in Mesembryanthemum crystallinum Plants during the Adaptation to Cadmium Stress

The common ice plants (Mesembryanthemum crystallinum) at the stage of five leaf pairs were exposed to cadmium chloride solutions (1, 0.1, and 0.01 mM) under the conditions of water culture. After five days, the partition of cadmium and iron in the plant organs and in the cell structures of the apical root region were investigated. Plant adaptation to excess cadmium in the environment was assessed by an increase in the leaf and root weight, a change in peroxidase activity, and an accumulation of proline. The common ice plant accumulated cadmium mainly in the root system. At a high concentration of cadmium in the nutrient solution (1 mM), its content in the root exceeded 2 g/kg fr wt, while at a concentration of 0.01 mM, it was as low as 10 mg/kg. Dithizone staining of transverse sections of the root apical region showed that, after a 48-h-long exposure of plants to 0.1 mM cadmium chloride, cadmium was localized in the cell walls of endodermis and metaxylem. The level of cadmium in leaves varied from 0.5 to 18 mg/kg fr wt. However, there was only a weak correlation between cadmium accumulation and the extent of a biomass decrease in the leaves of various stories, when cadmium concentration in the medium (1 mM cadmium chloride) was toxic. This fact could be related to a marked efflux of endogenous iron from old leaves into the young ones and to a change in the cadmium/iron ratio in the tissues. Proline accumulation in the third leaf pair and in the roots occurred at a relatively low cadmium content (10–12 mg/kg fr wt) in these organs. Maxima of activity of all three forms of peroxidase, viz., soluble, ionically-bound, and covalently-bound peroxidases, in roots were found at a high accumulation of cadmium in these organs (45 mg/kg fr wt). These maxima exceeded 3–4-fold the activity in aging leaves containing 5 mg cadmium/kg fr wt. A decrease in peroxidase activity in leaves was accompanied by a 3.3-fold decrease in iron content; thus, it could be caused by a deficiency of available iron necessary for the enzyme functioning. It was concluded that the resistance of Mesembryanthemum crystallinum, a halophyte, to excess cadmium content in the medium was achieved by its predominant accumulation in roots, where excess cadmium is compartmentalized in the apoplast and seems to be subjected to detoxification through pectate formation. Moreover, the leaves and, particularly, the roots are characterized by a high activity of the antioxidant systems, such as guaiacol-dependent peroxidases, and an occurrence of proline at modest cadmium concentrations.     

Silicon Alleviation of Cadmium Toxicity in Mangrove (Avicennia marina) in Relation to Cadmium Compartmentation

Mangrove plants seem to be highly tolerant of high levels of heavy-metal pollution. Recently, some researchers have focused on the mechanisms involved in their metal uptake and tolerance. However, the important mechanisms involved are still only partly understood. This investigation studied whether silicon (Si) affected cadmium (Cd) subcellular distribution in the leaves and root tips of Avicennia marina (Forsk.) Vierh seedlings, resulting in the amelioration of the toxicity of Cd. The results showed that Si partly overcame the reduction in growth due to Cd. This amelioration was correlated with a reduction in Cd uptake and alteration of Cd subcellular distribution. The mechanisms of Si amelioration of Cd stress were tissue dependent. In the leaves and root tips, Si reduced Cd concentration in subcellular fractions, Cd mobility, and the concentration of biologically active Cd in the cell wall active space. Si did not change the distribution of Cd between compartments in the leaves, but it increased the proportion of Cd in the cell walls and reduced the proportion of Cd in the symplast of the root tips.     

Identification of Barley Varieties Tolerant to Cadmium Toxicity

Two successive hydroponic experiments were carried out to identify barley varieties tolerant to Cd toxicity via examining Soil–Plant Analyses Development (SPAD) value, plant height, leaves and tillers per plant, root number and volume, and biomass accumulation. The results showed that SPAD values (chlorophyll meter readings), plant height, leaf number, root number and volume, and biomass accumulation of shoot/root were significantly reduced in the plants grown in 20 μM Cd nutrient solution compared with control, and the uptake and translocation of Zn, Mn, and Cu was also strictly hindered. Furthermore, there was a highly significant difference in the reduction in these growth parameters among varieties, and varieties “Weisuobuzhi” and “Jipi 1” showed the least reduction both in the two experiments, suggesting their high tolerance to Cd toxicity, while “Dong 17” and “Suyinmai 2” with the greatest reduction and the toxicity symptoms appeared rapidly and severely, denoting as Cd-sensitive varieties. Significant variety difference in Cd concentration was also found, with Weisuobuzhi containing the highest and Jipi 1 the lowest Cd concentration in shoots.     

Calcium Decreases Cadmium Concentration in Root but Facilitates Cadmium Translocation from Root to Shoot in Rice

Journal of Plant Growth Regulation - Understanding cadmium (Cd) accumulation in rice is important for the development of plant-based strategies for crop safety. Cd and calcium (Ca) are antagonistic...     

Structural Changes in Radish Seedlings Exposed to Cadmium

Radish (Raphanus sativus L. cv. Redondo Vermelho) seedlings were analysed by light and scanning electron microscopy to characterize the structural changes caused by the exposure to 0.5 or 1.0 mM cadmium chloride for 24, 48 and 72 h. The analyses showed changes in the anatomical and morphological characteristics of roots, stems and leaves of two-week-old seedlings. In all tissues, pressure potential was decreased. Premature death with the disintegration of the epidermis and an increase in the number of root hairs was observed in roots exposed to Cd. The stem of seedlings exposed to Cd exhibited more cells layers in the cambial region. The main effects observed in leaves in response to Cd were stomatal closure, lack of cell wall thickening and alterations in the shape of the chloroplasts. It is suggested that the structural changes observed in seedlings treated with Cd were mainly caused by a Cd-induced decrease in water uptake.     

Dietary Exposure to Lead and Cadmium in Yugoslavia

Abstract

Lead exposure still represents a matter of health concern especially in Yugoslavia. To assess the exposure of normal urban population to lead and cadmium through food, a preliminary monitoring was performed on a small group of urban population. Lead, cadmium and some essential elements (calcium, zinc, iron, copper and manganese) were analysed in collected duplicate diet samples and compared to similar population in Sweden. We found that dietary exposure to lead and cadmium is similar to other countries although Yugoslav urban population is exposed to much higher concentrations of lead in air than in cities of developed countries, due to high lead in gasoline. However, daily intake of some essential elements was significantly lower.

Also populations living around lead smelters in various parts of Yugoslavia are still exposed to elevated environmental lead and cadmium levels. To assess the exposure of the population living in this area, a cumulative long-term exposure to lead was determined by measuring lead in deciduous teeth. Concentrations of lead and cadmium in vegetables, soil and meals from the same region were also analysed. Values obtained for lead and cadmium in food products grown in exposed and control area were found to be related to respective concentrations of these elements in soil as well as to the distance from the smelter. Meals prepared in this region show the same trend, revealing very high intake particularly of lead.

The influence of nutritional factors, i.e. dietary calcium on lead metabolism, was also studied. Blood lead concentration was determined in two groups of peasant women living in two regions with different dietary calcium intake. Lower blood lead values were found in the higher dietary calcium intake region.