Reproductive toxicity and underlying mechanisms of di(2-ethylhexyl) phthalate in nematode Caenorhabditis elegans

DEHP (di(2-ethylhexyl) phthalate) is an endocrine disruptor commonly found in plastic products that has been associated with reproduction alterations, but the effect of DEHP on toxicity is still widely unknown. Using DEHP concentrations of 10, 1, and 0.1 mg/L, we showed that DEHP reduced the reproductive capacity of Caenorhabditis elegans after 72 hr. of exposure. DEHP exposure reduced the reproductive capacity in terms of decreased brood sizes, egg hatchability (0.1, 1 and 10 mg/L), and egg-laying rate (1 and 10 mg/L), and increased numbers of fertilized eggs in the uterus (1 and 10 mg/L). DEHP also caused damage to gonad development. DEHP decreased the total number of germline cells, and decreased the relative area of the gonad arm of all exposure groups, with worms in the 1 mg/L DEHP exposure group having the minimum gonad arm area. Additionally, DEHP caused a significant concentration‐dependent increase in the expression of unc-86. Autophagy and ROS contributed to the enhancement of DEHP toxicity in reducing reproductive capacity, and glutathione peroxidase and superoxide dismutase were activated as the antioxidant defense in this study. Hence, we found that DEHP has a dual effect on nematodes. Higher concentration (10 mg/L) DEHP can inhibit the expression of autophagy genes (atg-18, atg-7, bec-1, lgg-1 and unc-51), and lower concentrations (0.1 and 1 mg/L) can promote the expression of autophagy genes. Our data highlight the potential environmental risk of DEHP in inducing reproductive toxicity toward the gonad development and reproductive capacity of environmental organisms.     

Nickel accumulation and its effect on biomass, protein content and antioxidative enzymes in roots and leaves of watercress (Nasturtium officinale R. Br.)

In order to understand its response towards nickel stress,watercress(Nasturtium officinale R.Br.) was exposed to nickel(1-25 mg/L) for 1,3,5 and 7 days.The accumulation and translocation of nickel were determined and the influence of nickel on biomass,protein content and enzymatic antioxidants was examined for both roots and leaves.It was determined that N.officinale could accumulate appreciable amounts of Ni in both roots and leaves.Nickel accumulated particularly in the roots of plants.Biomass increased at low nickel concentrations but certain measurable change was not found at high concentrations.Under stress conditions the antioxidant enzymes were up-regulated compared to control.An increase in protein content and enzyme activities was observed at moderate exposure conditions followed by a decline at both roots and leaves.The maximum enzyme activities were observed at different exposure conditions.Our results showed that N.officinale had the capacity to overcome nickel-induced stress especially at moderate nickel exposure.Therefore,N.officinale may be used as a phytoremediator in moderately polluted aquatic ecosystems.     

Nickel accumulation and its effect on biomass, protein content and antioxidative enzymes in roots and leaves of watercress （Nasturtium officinale R. Br.）

In order to understand its response towards nickel stress, watercress (Nasturtium o cinale R. Br.) was exposed to nickel (1–25 mg/L) for 1, 3, 5 and 7 days. The accumulation and translocation of nickel were determined and the influence of nickel on biomass, protein content and enzymatic antioxidants was examined for both roots and leaves. It was determined that N. o cinale could accumulate appreciable amounts of Ni in both roots and leaves. Nickel accumulated particularly in the roots of plants. Biomass increased at low nickel concentrations but certain measurable change was not found at high concentrations. Under stress conditions the antioxidant enzymes were up-regulated compared to control. An increase in protein content and enzyme activities was observed at moderate exposure conditions followed by a decline at both roots and leaves. The maximum enzyme activities were observed at di erent exposure conditions. Our results showed that N. o cinale had the capacity to overcome nickel-induced stress especially at moderate nickel exposure. Therefore, N. o cinale may be used as a phytoremediator in moderately polluted aquatic ecosystems.     

Effect of herbicide acetochlor on cytochrome P450 monooxygenases and GST of earthworms Eisenia fetida

To assess the sublethal toxicity of the herbicide acetochlor to earthworms and to find out biomarkers possible inducted under acetochlor exposure, Eiseniafetida was exposed to artificial soils supplemented with different concentrations of acetochlor（5, 10, 20, 40 and 80 mg/kg soil）. Effects of the acetochlor on cytochrome P450 monooxygenases p-nitroanisole O-demethylase（ODM）, aldrin epoxidase（AE） and glutathione-S-transferases （GSTs） activities were determined. The results revealed cytochrome P450 monooxygenases were elevated with increasing concentrations of acetochlor, and the AE activity increased significantly compared with control at the concentration of 80 mg/kg （P〈0.05）. However, ODM activity from E. fetida was not induced significantly by acetochlor at all treatments（P〉0.05）. Sodium dodecyl sulfate-polyacryamide gel electrophoresis（SDS-PAGE） showed that one protein band was visualized and no evident differences were found in protein profiles between treatments and control. The GST activity increased significantly with longer duration（P〈0.05） and increasing concentrations of acetochlor exposure（P〈0.05）. This study showed that the monooxygenases and GSTs activities in E. fetida could be induced by acetochlor, and thus, the AE and GST could be used in sublethal assays for soil contamination surveys and GST could be used as biomarkers of acetochlor exposure in E. fetida.     

Alterations of endogenous metabolites in urine of rats exposed to decabromodiphenyl ether using metabonomic approaches

There is large usage of polybrominated diphenyl ethers （PBDEs） especially for decabromodiphenyl ether （BDE-209, Deca-BDE） in controlling the risks of fire. The toxicological effects of PBDEs are worth being concerned about. Female SD rats were daily gavaged with BDE-209 ether at the dose of 100 mg/kg for 20 days. Histological observation was performed for the screening of the target organs for BDE-209 exposure. The distribution and metabolism of PBDEs in the exposed main organs were evidenced by HRGC-HRMS. Alterations of the endogenous metabolite concentrations in urine were investigated using metabonomic approaches based on IH NMR spectrum. Histopathological changes including serious edema in kidney, hepatocellular spotty necrosis and perivasculitis in liver indicated that BDE-209 caused potential influences on endogenous metabolism in the exposed liver and the kidney. BDE-209 was found to be highly accumulated in lipid, ovary, kidney and liver after 20 days＇ exposure. Occurrence of other lower brominated PBDEs in the rats demonstrated that reductive debromination process happened in vivo. Hydroxylated and methoxylated-BDEs, as metabolism products, were also detected in the rat tissues. A total of 12 different endogenous metabolites showed obvious alterations in urine from the exposed rats, indicating the disturbance of the corresponding internal biochemical processes induced by BDE-209 exposure. These findings in vivo suggested the potential health risk might be of concern due to the toxicological effects of BDE-209 as a ubiquitous compound in the environment.     

Upper Yellow River air concentrations of organochlorine pesticides estimated from tree bark, and their relationship with socioeconomic indices

Organochlorine pesticide(OCP) concentrations in tree bark from the upper Yellow River region were determined. Total OCP concentrations ranged from 2.7 to 82 ng/g dw, with a mean of 20 ng/g dw. Concentrations of total(Σ) DDTs(0.49–37 ng/g dw), HCHs(0.55–4.5 ng/g dw), and HCB(0.1–1.0 ng/g dw) were much higher than the other OCPs and accounted for 89% of the ΣOCP concentrations. p,p′-DDT was the dominant member of the DDT pesticide group and-HCH was the dominant HCH isomer. The p,p′-DDT/p,p′-DDE and-HCH/-HCH ratios suggested that there were recent DDT and-HCH releases. OCP concentrations in the air were estimated from the tree bark, and the estimated median ΣDDTs, ΣHCHs, and HCB concentrations in the air were 0.09, 0.14, and 0.024 pg/m3, respectively. The relationship between total OCP concentrations and socioeconomic and natural environment indices were assessed using multiple linear regression analysis, and a regression equation including all these factors was obtained. Population density and tertiary industry were the two dominant factors that appeared to affect OCP concentrations in the upper Yellow River region.     

Effects of chronic exposure to nonylphenol on locomotor activity and social behavior in zebrafish (Danio rerio)

Nonylphenol(NP),a xenoestrogen ubiquitously found in aquatic ecosystems,is of high environmental concern.The present work assessed the effects of exposure to NP on locomotor activity and social behavior in male and female zebrafish(Danio rerio),to evaluate the possible hazard of NP to fish behavior and to pursue a potential biomarker of NP contamination.Fish were randomly divided into six groups.Five groups were receiving 0.1,1,10,50 and 100 μg/L nominal concentrations of NP for 60 days,respectively.A sixth control group was given the same treatment as the other five groups,but no NP.Locomotor activity,aggressive behavior,group preference and leaving shoal were examined.NP exposure showed marked influence on locomotor activity of the male zebrafish,whereas that of the female was not significantly affected by NP.Aggressive behavior and group preference were significantly affected by NP exposure in both male and female groups.Locomotor activity and aggressive behavior of the male and group preference of both male and female zebrafish were clearly inhibited at 100 μg/L NP.No significant alteration in leaving shoal was observed under NP exposure.The results suggested that changes in locomotor activity and aggressive behavior of the male and group preference of both male and female may be used as an ecologically relevant integrative biomarker of NP contamination.     

Distribution of persistent organochlorine pesticides in tissue/organ of silver carp (Hypophthalmichthys molitrix) from Guanting Reservoir, China

The concentration of organochlorine pesticides（OCPs） in tissues and organs of silver carp（Hypophthalmichthys mofitrix） from Guanting Reservoir were investigated to evaluate the pollution potential and distribution of OCPs. A total of 16 OCPs were measured and the concentrations were in the range of 1.61-69.01 ng/g wet weight（ww） for total OCPs, 0.16- 0.75 ng/g ww for HCB. 0.75 -26.80 ng/g ww for SHCH（sum of α-,β-, γ- and δ-HCH） and 0.68-35.94 ng/g ww for SDDT（ sum of p, p＇-DDE, p, p＇-DDD, o, p＇-DDT and p, p＇- DDT）. The mean concentrations of total OCPs, HCB, ∑HCH, and ∑DDT were 18.04, 0.96, 7.14 and 9.28 ng/g ww, respectively. Among the organochlorine pesticides, β-HCH and p, p＇-DDE were the most dominant compounds in tissue and organ with the average concentrations of 4.42 and 8.14 ng/g, respectively. The results obtained in this study show that the levels of 16 OCP residues found in silver carps are low and pose no threat to human health and wildlife fed upon them on the basis of existing related quality guidelines. However, recent input of lindane and DDT might still exist in the area investigated and further investigation should be carried on.     

Effects of p,p'-DDE exposure on gonadal development and gene expression in Japanese medaka (Oryzias latipes)

Although 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE),the major and most persistent metabolite of dichlorodiphenyl-trichloroethane (DDT),was continually detected in wild fishes that showed abnormal gonad development such as intersex,little is known about the impact of p,p'-DDE exposure on gonad development in fishes.To survey the effects of p,p'-DDE on gonadal development and gene expressions,male juvenile (20-d post hatch) Japanese medaka (Oryzias latipes) was exposed to 1,5,20,and 100 μg/L p,p'-DDE for two months.Increased hepatosomatic index (HSI) and decreased gonadosomatic index (GSI) were found in the p,p'-DDE-treated groups.Intersex was found in 100 μg/L p,p'-DDE exposure group,as well as 100 ng/L 17α-ethynylestradiol (EE2)group.By quantitative real-time RT-PCR,it was found that gene expressions of vitellogenins (VTG-1,VTG-2),choriogenins (CHG-H,CHG-L),and estrogen receptor α (ER-α) in the liver of the fish were significantly up-regulated by p,p'-DDE exposure.VTC-1 and VTG-2 were recommended as the preferred biomarker for assessing anti-androgenic p,p'-DDE because they were the highest up-regulated among the genes and showed good dose-response relationship.The up-regulated ER-α suggested that a potential synergetic effect would occur when p,p'-DDE coexists with other ER-α-binding endocrine-disrupting chemicals (EDCs).     

五氯酚对稀有鮈鲫胚胎毒性效应研究

研究五氯酚(PCP)对稀有鮈鲫(Gobiocypris rarus)胚胎的致畸和毒性效应.以7.5,30,60,120,250μg/L5个浓度的PCP对0hpf(hpf,受精卵孵出时间)的稀有鮈鲫胚胎进行暴露染毒,同时设置空白对照组、二甲基亚砜溶剂对照组和雌二醇(EE2,2.5ng/L)阳性对照组.在立体显微镜下观察整个胚胎的发育过程,统计胚胎的孵化率、96hpf相对存活率和各时期的畸形率,并利用半定量RT-PCR检测胚胎中CYP1A基因和p53基因mRNA的表达.结果表明,PCP暴露能延迟稀有鮈鲫胚胎发育,并造成胚胎卵凝结、心包囊肿、脊柱弯曲等多种畸形甚至死亡.随着PCP暴露浓度的升高,稀有鮈鲫胚胎的孵化率和96hpf相对存活率降低,各时期的畸形率增加,并呈现一定的浓度效应.稀有鮈鲫胚胎CYP1A基因和p53基因mRNA表达被显著诱导,并随PCP浓度的升高而增加.PCP对稀有鮈鲫胚胎发育表现为显著的毒性效应.稀有鮈鲫胚胎孵化率、96hpf相对存活率、各时期畸形率及CYP1A基因和p53基因的诱导表达可以作为评价PCP毒性作用的敏感指标.     

有机质对p,p′-DDE在土壤中的吸附影响

为研究有机质对p, p′-DDE在土壤中的吸附影响因素,采用批量试验方法,分析p, p′-DDE在包气带土壤及含水层土壤上吸附量的变化及有机质对p, p′-DDE在土壤中的吸附影响.结果表明,p, p′-DDE在土壤中的吸附均符合先快后慢、最后达到吸附平衡的规律;其吸附动力学曲线用一级和二级反应动力学方程均能较好拟合,说明p, p′-DDE在这两种物质中的吸附以简单吸附为主,同时包含表面吸附、颗粒内部扩散等过程.包气带土壤和含水层土壤等温吸附线的拟合相关系数(R2)均大于0.95,符合Freundlich模型和线性模型,而含水层样品与Freundlich模型拟合得更好,表明p, p′-DDE在包气带土壤中的吸附以单分子层吸附为主,而在含水层土壤中的吸附还伴随着多分子层吸附的复杂过程;去除内源DOM(溶解性有机质)后,样品对p, p′-DDE的吸附量呈增加趋势,按吸附增加量由小到大的排序为1-1(0~10 cm) < 1-2(120~150 cm) < 2-4(100~120 cm),说明内源DOM的存在总体上抑制了p, p′-DDE的吸附,并且w(DOM)越高,其抑制作用越强;外源DOM的加入抑制了土壤对p, p′-DDE的吸附;去除有机质后样品对p, p′-DDE的吸附量与w(黏土矿物)具有正相关性.研究显示,有机质对土壤中有机污染物的吸附迁移研究对土壤修复有重要意义,需要对有机质影响土壤的吸附机制进行更深层次的研究.      

壬基酚在鱼体组织中的累积及对鱼类性腺的影响

采用HPLC法测定了在一定条件下暴露后鲤鱼和草鱼体内壬基酚的含量和分布,分析了鱼类性腺重量的变化.结果表明,在试验浓度下,20～25d后鲤鱼和草鱼体内的壬基酚可达到累积和释放的动态平衡,其最大累积系数分别为84.3和78.8,累积规律为鲤鱼>草鱼,肝脏>肌肉.受试雌鱼的性腺重量有明显的提高,相当于100ng/L17β-雌二醇(E₂)作用下鱼类性腺重量的34%～41%,表明壬基酚对鱼类具有一定的雌激素活性,且壬基酚的生物累积性和雌激素活性在产生时间和活性数值方面均是同步的和成正相关的.     

氟对斑马鱼生殖毒性研究

为了探讨氟对鱼类的生殖毒性效应,以成年斑马鱼为试验对象,氟化钠暴露45 d和90 d后,运用组织切片观察斑马鱼性腺组织的发育情况,采用酶联免疫分析法测定性腺中雌二醇（Estradiol,E2）、卵黄蛋白原（Vitellogenin,VTG）和睾酮（Testosterone,T）的含量,并使用实时荧光定量PCR方法检测斑马鱼生殖相关基因的表达水平.结果显示：氟暴露会阻滞成年斑马鱼性腺发育,造成卵泡发育不良,精巢生精能力下降;同时降低雌性斑马鱼性腺中E2和VTG的含量,增加T的含量;雌性斑马鱼孕酮受体（Prg）和糖皮质激素受体（GR）基因相对表达量随氟浓度的增加呈先降后升的趋势,随着染毒剂量与时间的增加,雄激素受体（AR）基因相对表达量逐渐增加,而CYP19a基因相对表达量逐渐减少.雄性斑马鱼性腺中E2、VTG、T的含量及生殖相关基因表达的变化趋势则与雌性斑马鱼相反.综上所述,氟暴露可以通过影响斑马鱼体内性腺发育、E2、VTG、T含量及生殖相关基因表达来影响其生殖功能.实验结果可为进一步研究氟化物对水生动物的生殖毒性效应提供理论依据.     

Effects of ZnO nanoparticles on perfluorooctane sulfonate induced thyroid-disrupting on zebrafish larvae

Perfluorooctane sulfonate(PFOS) and ZnO nanoparticles(nano-ZnO) are widely distributed in the environment.However,the potential toxicity of co-exposure to PFOS and nano-ZnO remains to be fully elucidated.The test investigated the effects of co-exposure to PFOS and nano-ZnO on the hypothalamic–pituitary–thyroid(HPT) axis in zebrafish.Zebrafish embryos were exposed to a combination of PFOS(0.2,0.4,0.8 mg/L) and nano-ZnO(50 mg/L)from their early stages of life(0–14 days).The whole-body content of TH and the expression of genes and proteins related to the HPT axis were analyzed.The co-exposure decreased the body length and increased the malformation rates compared with exposure to PFOS alone.Co-exposure also increased the triiodothyronine(T3) levels,whereas the thyroxine(T4)content remained unchanged.Compared with the exposure to PFOS alone,exposure to both PFOS(0.8 mg/L) and nano-ZnO(50 mg/L) significantly up-regulated the expression of corticotropin-releasing factor,sodium/iodidesymporter,iodothyronine deiodinases and thyroid receptors and significantly down-regulated the expression of thyroid-stimulating hormone,thyroglobulin(TG),transthyretin(TTR) and thyroid receptors.The protein expression levels of TG and TTR were also significantly down-regulated in the co-exposure groups.In addition,the expression of the thyroid peroxidase gene was unchanged in all groups.The results demonstrated that PFOS and nano-ZnO co-exposure could cause more serious thyroid-disrupting effects in zebrafish than exposure to PFOS alone.Our results also provide insight into the mechanism of disruption of the thyroid status by PFOS and nano-ZnO.     

燃料油水溶液对牙鲆幼鱼的细胞毒性及DNA损伤

海洋溢油污染是当前世界各国普遍关注的环境问题之一,本实验以牙鲆(Paralichthys olivaceus)幼鱼为受试生物,研究了低剂量燃料油水溶液暴露对牙鲆幼鱼肝脏和鳃组织中超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化氢酶(Catalase,CAT)、过氧化物酶(Peroxidase,POD)、谷胱甘肽转硫酶(Glutathione S-transferase,GST)活性和脂质过氧化(Lipid peroxidation,LPO)水平、血细胞溶酶体膜稳定性的影响以及产生的DNA损伤。结果表明:(1)抗氧化酶活性及脂质过氧化水平对燃料油胁迫的响应存在明显的组织差异,且同一种酶活性在不同的时间对燃料油污染的响应也不同;(2)溶酶体膜稳定性随着燃料油浓度增大与实验时间的延长而降低(P0.05),解除污染后低浓度组(0.001 mg/L)恢复至对照组水平(P0.05),中(0.010 mg/L)、高(0.100 mg/L)浓度组则不能恢复至对照组水平(P0.05);(3)燃料油暴露可使牙鲆血细胞DNA受到明显损伤,染毒第15 d,低浓度组组与中浓度组血细胞DNA损伤为中度损伤,高浓度组为重度损伤,解除污染6 d后,低浓度组与中浓度组组恢复至轻度损伤,高浓度组恢复至中度损伤。因此,燃料油污染会对牙鲆造成脂质过氧化损伤,影响血细胞溶酶体膜的稳定性,最终对生物产生遗传损伤。     

甲醛对原癌基因c-myc、MDM2及抑癌基因p53的影响

为研究吸入性甲醛的毒性能否进入动物骨髓组织,引起骨髓组织基因表达发生改变,选择小鼠某些原癌基因和抑癌基因为研究对象,以SPF级balb/c雄性小鼠为材料,采用动态吸入方式染毒2周(5+2模式),染毒浓度分别为0, 0.5, 3.0mg/m3,用半定量RT-PCR方法检测不同浓度甲醛对小鼠染毒后骨髓组织细胞中c-myc、MDM2和p53基因表达的变化.结果表明,在不同浓度的甲醛暴露条件下,与空白对照组相比,小鼠骨髓组织中的c-myc基因,MDM2基因和p53基因表达均发生改变,在3.0mg/m3浓度组与空白对照组存在显著差异(P<0.05), c-myc基因,MDM2基因呈现表达上调,p53基因则呈现表达下调.吸入性甲醛的毒性能进入动物骨髓组织,并能引起骨髓组织基因表达发生改变.     

Bioaccumulation and the expression of hepatic cytochrome P450 genes in marine medaka (Oryzias melastigma) exposed to difenoconazole

This study was conducted to assess the effects of difenoconazole (DFZ), a triazole fungicide, on the hepatic biotransformation system and its bioaccumulation in marine medaka (Oryzias melastigma). Fish were exposed to DFZ (1, 10, 100, 1000 ng/L) for 180 days. The results showed that: (1) The mRNA levels of hepatic CYP1A1, CYP1B, CYP1C1, CYP27B and CYP3A40 were up-regulated, but those of CYP3A38 and CYP27A1 were down-regulated. (2) The activity of ethoxyresorufin-O-deethylase (EROD) and the content of reduced glutathione (GSH) in the liver were increased in the DFZ-treated groups, and glutathione S-transferase (GST) activity was increased in the 100 and 1000 ng/L groups. (3) DFZ was accumulated in the muscle and the biological concentration factors in the 10, 100, and 1000 ng/L groups were respectively 149, 81 and 25. These results suggested that long-term exposure to DFZ at low concentrations would result in a bioaccumulation of this compound and disturb the biotransformation system.     

Toxic effects of crude-oil-contaminated soil in aquatic environment on Carassius auratus and their hepatic antioxidant defense system

Under the indoor simulant conditions, toxic effects of crude-oil-contaminated soil which was put into aquatic environment on the young fishes Carassius auratus and their hepatic antioxidant system after a 20-d exposure were investigated. Results showed that the relationship between the mortality of C. auratus and the exposed doses could be divided into 3 phases: fishes exposed to the low dose groups (0.5-5.0 g/L) were dead due to the ingestion of crude-oil-contaminated soils in aquatic environment; at the m...