Glycine-β-cyclodextrin-assisted cometabolism of phenanthrene and pyrene by Pseudomonas stutzeri DJP 1 from marine sediment

Cometabolic degradation is currently an effective and extensively way to remove high molecular weight polycyclic aromatic hydrocarbons(HMW-PAHs).Unfortunately,due to low bio-accessibility and high biotoxicity,the cometabolic degradation rate of HMW-PAHs is limited.Glycine-β-cyclodextrin(GCD)was obtained through amino modification ofβ-cyclodextrin(BCD)and added to cometabolic system of phenanthrene(PHE)and pyrene(PYR)to assist PYR biodegradation.Results show that the addition of GCD(100 mg/L)effectively improved the removal rate of PYR(20 mg/L)by 42.3%.GCD appeared to increase the bio-accessibility and reduce the biotoxicity of PHE and PYR,and then promoted the growth of Pseudomonas stutzeri DJP1 and stimulated the elevation of dehydrogenase(DHA)and catechol 12 dioxygenase(C12O)activities.The phthalate metabolic pathway was accelerated,which improved the cometabolic degradation.This study provided a new reference for the cometabolic degradation of HMW-PAHs.

Switch of phosphorylation to O-GlcNAcylation of AhR contributes to vascular oxidative stress induced by benzo[a]pyrene

Benzo[a]pyrene(B[a]P)is a food contaminant toxic for cardiovascular diseases.The nuclear translocation of Arylhydrocarbon receptor(AhR)plays an important role in B[a]P-induced oxidative stress and vascular diseases.We confi rmed that B[a]P promoted ROS production in vascular smooth muscle cells(VSMCs)in vitro and in vivo,associated with the nuclear translocation of AhR.It is known that phosphorylation inhibits while dephosphorylation of AhR promotes nuclear translocation of AhR.However,from the posttranslational modifi cation level,the mechanism by which B[a]P activates and regulates the nuclear translocation of AhR is unclear.Co-immunoprecipitation results showed that cytoplasmic AhR was phosphorylated before B[a]P stimulation,and switched to O-GlcNAcylation upon B[a]P 1-h stimulation in VSMCs,suggesting there may be a competitively inhibitory relationship between O-GlcNAcylation and phosphorylation of AhR.Next,siRNAs of O-linked N-acetylglucosamine transferase(OGT),O-GlcNAcase(OGA)and OGA inhibitor PUGNAc were used.SiOGT blocks but siOGA and PUGNAc promote B[a]P-dependent AhR nuclear translocation and oxidative stress.Ser11 may be the competitive binding site for phosphorylation and O-GlcNAcylation of AhR.Phosphorylation-mimic variant inhibits but O-GlcNAcylation of AhR promotes AhR nuclear translocation and oxidative stress.Our fi ndings highlight a new perspective for AhR nuclear translocation regulated by the competitive modifi cation between phosphorylation and O-GlcNAcylation.

基于β-糊精氧化石墨烯管尖固相萃取/高效液相色谱检测生活饮用水中苯并[a]芘

以自制的β-糊精氧化石墨烯(β-CD@GO)装填入10mL移液器吸头作为固相萃取剂,结合高效液相色谱法对生活饮用水中苯并[a]芘进行检测,并对固相萃取条件进行了优化。苯并[a]芘在0.1~50μg/L范围内线性关系良好(r=0.9996),检出限为3ng/L(S/N=3)。在加标水平为0.5、5、40μg/L时,方法回收率为89.2%~92.5%,相对标准偏差为3.7%~5.2%。该方法操作简便快速、选择性好、灵敏度高、有机溶剂消耗少,可用于生活饮用水中苯并[a]芘快速检测分析。

Inhibitory effects of RRR-α-tocopheryl succinate on benzo (a) pyrene (B (a) P)-induced forestomach carcinogenesis in female mice

AIM To study the inhibitory effects of VES( RRR-α-tocopheryl Succinate, VES ), aderivative of natural Vitamin E, on benzo (a)pyrene (B (a) P)-induced forestomach tumor infemale mice.METHODS The model of B (a)P-inducedforestomach tumor was established according tothe methods of Wattenberg with slightmodifications. One hundred and eighty femalemice (6 weeks old) were divided into six groupsequally; negative control (Succinic acid),vehicle control ( Succinate + B (a) P), positivecontrol(B(a) P), high VES(2.5g/kg. b. w + B(a)P), Iow VES(1 .25 g/kg. b. w + B(a) P) ig as wellas VES by ip (20 mg/kg, b. w + B(a) P). Exceptthe negative control group, the mice wereadministrated with B(a)P ig. and correspondingtreatments for 4 weeks to study the anti-carcinogenetic effect of VES during the initiationperiod. The experiment lasted 29 weeks, inwhich the inhibitory effects of VES both ontumor incidence and tumor size were tested.RESULTS The models of B (a)P-inducedforestomach tumor in female mice wereestablished successfully. Some werecauliflower-like, others looked like papilla, evena few were formed into the ulcer cavities. VES at1.25 g/kg. b. w, 2.5 g/kg. b.w. by ig and 20 mg/kg. b. w. via ip could decrease the number oftumors per mouse (1.7 ± 0. 41, 1.6 ± 0.34 and 1.1±0.43), being lower than that of B(a)P group(5.4 ± 0.32, P＜0.05). The tumor incidence wasinhibited by 18.2%, 23.1% and 50.0%. VES at1.25g/kg.b.w., 2.5 g/ kg.b.w. by ig and20 mg/kg. b.w. via ip reduced the total volumeof tumors per mouse (54.8 ± 8.84, 28.4 ± 8.32and 23.9± 16.05), being significantly lower thanthat of B(a)P group (150.2±20.93, P＜0.01).The inhibitory rates were 63.5%, 81.1% and84.1%, respectively.CONCLUSION VES has inhibitory effects on B(a) P-induced forestomach carcinogenesis infemale mice, especially by ip and it may be apotential anti-cancer agent in vivo.

Biodegradation of benzo[a]pyrene in soil by Mucor sp.SF06 and Bacillus sp.SB02 co-immobilized on vermiculite

Two indigenous microorganisms, Bacillus sp. SB02 and Mucor sp. SF06, capable of degrading polycyclic aromatic hydrocarbons （PAHs） were co-immobilized on vermiculite by physical adsorption and used to degrade benzo[a] pyrene （BaP）. The characteristics of BaP degradation by both free and co-immobilized microorganism were then investigated and compared. The removal rate using the immobilized bacterial-fungal mixed consortium was higher than that of the freely mobile mixed consortium. 95.3% of BaP was degraded using the co-immobilized system within 42 d, which was remarkably higher than the removal rate of that by the free strains. The optimal amount of inoculated co-immobilized system for BaP degradation was 2%. The immobilized bacterial-fungal mixed consortium also showed better water stability than the free strains. Kinetics of BaP biodegradation by co-immobilized SF06 and SB02 were also studied. The results demonstrated that BaP degradation could be well described by a zero-order reaction rate equation when the initial BaP concentration was in the range of 10--200 mg/kg. The scanning electronic microscope （SEM） analysis showed that the co-immobilized microstructure was suitable for the growth of SF06 and SB02. The mass transmission process of co-immobilized system in soil is discussed. The results demonstrate the potential for employing the bacterial-fungal mixed consortium, co-immobilized on vermiculite, for in situ bioremediation of BaP.

Antioxidant responses to benzo[a]pyrene,tributyltin and their mixture in the spleen of Sebasticus marmoratus

It has been reported that there is an interaction between Benzo[a]pyrene （BaP）, a widespread carcinogenic polycyclic aromatic hydrocarbon, and tributyltin （TBT）, an organometal used as an antifouling biocide. This study was therefore designed to examine the potential in vivo influence of BaP, TBT and their mixture on splenic antioxidant defense systems of Sebastiscus marmoratus. The fish were exposed to water containing environmentally relevant concentrations of BaP, TBT and their mixture. Spleens were collected for biochemical analysis after exposure for 7, 25, 50 d and after recovery for 7, 20 d. Cotreatment with BaP and TBT for 7 d potentiated the induction of glutathione peroxidase （GPx） activity by BaP or TBT alone. The cotreatment for 25 and 50 d resulted in inhibition of GPx activity, which was similar to the effect of TBT. Splenic glutathione S-transferase （GST） activities were significantly elevated in S. marmoratus exposed to BaP starting from 7 d and remained high up to 25 d. However, no further activity change was found with prolonged exposure. Cotreatment of BaP and TBT primarily inhibited the GST activity, which was similar to the effect of TBT. Cotreatment with BaP and TBT for 25 or 50 d potentiated the depletion of GSH （glutathione） by BaP or TBT alone. MDA （malondialdehyde） contents in spleen of S. marmoratus were not significantly altered compared with the control during the test period. Spleen, as an immune organ, is sensitive to exposure of BaP or TBT. It should have an effective mechanism to counteract oxidative damage. Antioxidative defense systems in spleen of S. marmoratus should be considered as potential biomarkers. Short-term exposure of BaP or TBT could result in induction of antioxidant defense system. A significant decrease of these indices, such as GSH, GST, GPx might indicate more severe contamination.

Photochemical behavior of benzo[a]pyrene on soil surfaces under UV light irradiation

The rates of photodegradation and photocatalysis of benzo [a]pyrene （BaP） on soil surfaces under UV light have been studied. Different parameters such as temperature, soil particle sizes, and soil depth responsible for photodegradation, catalyst loads and wavelength of UV irradiation blamed for photocatalysis have been monitored. The results obtained indicated that BaP photodegradation follows pseudo-first-order kinetics. BaP photodegradation was the fastest at 30℃ . The rates of BaP photodegradation at different soil particle size followed the order： less than 1 mm〉less than 0.45 mm〉less than 0.25 mm. When the soil depth increased from 1 mm to 4 ram, the half-life increased from 13.23 d to 17.73 d. The additions of TiO2 or Fe2O3 accelerated the photodegradation of BaP, and the photocatalysis of BaP follows pseudo-first-order kinetics. Changes in catalyst loads of TiO2 （0.5%, 1%, 2%, and 3% （wt）） or Fe203 （2%, 5%, 7%, and 10% （wt）） did not significantly affect the degradation rates. Both BaP photocatalysis in the presence of TiO2 and Fe2O3 were the fastest at 254 nm UV irradiation.

苯并[a]芘恶性转化16HBE细胞元素组分析及铜与顺铂或长春瑞滨联用对细胞增殖的作用

目的研究苯并[a]芘(BaP)致细胞恶性转化中元素组的变化,探讨铜与顺铂或长春瑞滨联用对细胞增殖的影响。方法以16HBE细胞和BaP恶性转化细胞T-16HBE-C1细胞为研究对象,采用电感耦合等离子质谱分析44种元素在2种细胞中的含量,采用偏最小二乘回归分析元素含量对2种细胞的区分能力,采用MTT法检测铜(0,237,340,487,1000和1432μmol·L^(-1))、顺铂(0,4.4,6.1,8.6,12.0和16.8μmol·L^(-1))和长春瑞滨(0,3.8,9.8,25.0,40.0和64.0μmol·L^(-1))对2种细胞存活率的影响,计算半数抑制浓度(IC_(50))。根据IC_(50)比例制备铜与顺铂混合物和铜与长春瑞滨混合物,采用MTT法检测其对细胞存活率的影响,并采用等效线图法分析铜与顺铂或长春瑞滨的联合作用。采用MTT法检测铜(0,50,100,200,400和800μmol·L^(-1))与IC_(50)的顺铂或长春瑞滨联用对T-16HBE-C1细胞存活率的影响。结果在2种细胞中共检出29种元素,其中铜、锌、银、硒和铷含量在T-16HBE-C1细胞中较16HBE细胞降低(P<0.01,P<0.05),钼、砷、锂、锗、锶、镍、镧、汞、铁和铯含量升高(P<0.01,P<0.05)。元素含量可用于区分16HBE和T-16HBE-C1细胞。铜可抑制16HBE和T-16HBE-C1细胞增殖,IC_(50)分别为(613±16)μmol·L^(-1)和(776±15)μmol·L^(-1)(P<0.01)。铜与顺铂混合物(1∶69.5)和铜与长春瑞滨混合物(1∶33.4)抑制T-16HBE-C1细胞增殖,且铜与顺铂和长春瑞滨具有相加作用。与单独IC_(50)浓度的顺铂(11.2μmol·L^(-1))或长春瑞滨(23.2μmol·L^(-1))相比,当铜>400μmol·L^(-1),其与IC_(50)浓度的顺铂或长春瑞滨联合作用可抑制T-16HBE-C1细胞增殖。结论16HBE细胞经BaP恶性转化后元素含量和相关关系发生改变。铜可抑制T-16HBE-C1细胞增殖,且在高浓度时与顺铂和长春瑞滨具有相加的联合作用。

Isolation of marine benzo[a]pyrene-degrading Ochrobactrum sp. BAP5 and proteins characterization

A bacterial strain BAP5 with a relatively high degradation ability of benzo[a]pyrene （BaP） was isolated from marine sediments of Xiamen Western Sea, China and identified as Ochrobactrum sp. according to 16S rRNA gene sequence as well as Biolog microbial identification system. Strain BAP5 could grow in mineral salt medium with 50 mg/L of BaP and degrade about 20% BaP after 30 d of incubation. Ochrobactrum sp. BAP5 was able to utilize other polycyclic aromatic hydrocarbons （PAHs） （such as phenanthrene, pyrene and fluoranthene） as the sole carbon source and energy source, suggesting its potential application in PAHs bioremediation. The profile of total soluble protein from Ochrobactrum sp. BAP5 was also investigated. Some over- and special-expressed proteins of strain BAP5 when incubated with the presence of BaP were detected by two-dimensional polyacrylamide gel electrophoresis, and found to be related with PAHs metabolism, DNA translation, and energy production based on peptide fingerprint analysis through matrix-assisted laser desorption/ionization-time of flight mass spectrometry.

苯并(a)芘诱导的肺细胞癌变过程中时间异质性的拉曼光谱分析

目的肺癌在生物学特性、基因组变异、增殖速度及化疗响应方面的时间异质性,构成了对有效治疗的显著阻碍。肺癌时间异质性的复杂性,结合其空间异质性,为研究带来了极大挑战。本文将为肺癌研究开辟新的方向,有助于更深入地理解肺癌的时间异质性,从而提升对肺癌的治疗成功率。方法应用拉曼光谱显微技术作为监测肺癌细胞生物分子组成实时变化的有力工具,揭示了疾病的时间异质性。通过拉曼光谱与多元统计分析的结合,对苯并(a)芘处理后人类肺上皮细胞的生物分子变化进行了细致观察。结果随时间推移,核酸、脂质、蛋白质及类胡萝卜素含量呈现下降趋势,而葡萄糖浓度上升。这些变化模式暗示,苯并(a)芘可导致遗传物质结构损伤、促进脂质过氧化、干扰蛋白质代谢、降低类胡萝卜素生成,并改变葡萄糖代谢路径。运用拉曼光谱技术,以实时、无侵入性、非破坏性的方式监控肺癌细胞内的生物分子动态,进而阐明其关键分子特性。结论本项研究深化了对肺癌演进的认识,并为发展个性化治疗策略提供支持,助力提升患者的临床治疗效果。

In vitro Study on Role of Hsp70 Expression in DNA Damage of Human Embryonic Lung Cells Exposed to Benzo[a]pyrene

Objective Benzo[a]pyrene (B[a]P), a ubiquitous environmental pollutant, is a potent procarcinogen and mutagen that can elicit tumors, leading to malignancy. Heat shock proteins (Hsp) have been shown to protect cells against damages caused by various stresses including exposure to numerous chemicals. Whether Hsps, or more specifically Hsp70, are involved in repair of B[a]P-induced DNA damage is currently unknown. Methods We assessed the potential role of the inducible form of Hsp70 in B[a]P-induced DNA damage of human embryonic lung (HEL) cells using immunoblot and the comet assay (i.e., the single cell gel electrophoresis assay). Results Exposure to B[a]P induced a dose-dependent decrease in the level of Hsp70, but a dose-dependent +-increase in DNA damage both in untreated (control) HEL cells and in cells preconditioned by a heat treatment. Heat preconditioning prior to B[a]P exposure potentiated the effect of B[a]P at a low dose (10 μmol/L), but appeared to be protective at higher doses. There was a negative correlation between Hsp70 level and DNA damage in the non-preheated as well as in the preconditioned cells. Conclusion These data suggest that exposure of HEL cells to B[a]P may induce a dose-dependent reduction in the levels of the inducible Hsp70. The detailed mechanisms for the reduction of Hsp70 levels by B[a]P and the role of Hsp70 in DNA damage under different concentrations of B[a]P remains to be determined.

金针菇多糖通过调节髓系细胞生成缓解苯并[a]芘染毒小鼠血管炎症

金针菇多糖(Flammulina velutipes polysaccharide,FVP)具有良好的抗炎、抗氧化作用。为进一步探讨FVP缓解血管损伤的效果和作用机制,构建苯并[a]芘(benzo[a]pyrene,Ba P)小鼠染毒模型,通过免疫组化检测血管炎症因子表达量;使用流式细胞术分析外周血和脾脏中促炎细胞比例及骨髓造血细胞亚群构成。结果显示,FVP处理缓解Ba P诱导的白介素-6、单核细胞趋化蛋白-1和细胞间黏附分子-1等血管促炎因子的表达。此外,FVP处理显著抑制Ba P诱发的小鼠外周血中单核细胞、巨噬细胞和中性粒细胞以及脾脏中巨噬细胞和中性粒细胞比例的增加。进一步分析骨髓造血细胞亚群构成发现,Ba P处理后增加了小鼠骨髓中造血祖细胞和粒细胞巨噬细胞祖细胞的比例,减少了造血干细胞和普通髓系祖细胞的比例,而FVP处理后逆转了这一现象,使骨髓造血细胞亚群恢复至健康对照水平。同时细胞水平上的研究表明,FVP可抑制Ba P诱导Raw264.7细胞产生的氧化应激。综上,FVP可能是通过维持骨髓造血系统的稳态、调节促炎细胞向循环系统的输出和下调外周促炎细胞的比例缓解Ba P引发的血管炎症损伤。

苯并[a]芘和慢性压力应激暴露对小鼠肝脏代谢的影响

环境污染和慢性压力是影响人类健康的两大类常见风险因子,本研究通过表征苯[a]并芘(benzo[a]pyrene,B[a]P)与慢性压力应激(chronic unpredictable mild stimulation,CUMS刺激)暴露对小鼠肝脏代谢的影响,并探讨了同时暴露时两大风险因子之间潜在的相互作用.采用靶向代谢组学结合多元统计学方法分析了两个剂量B[a]P(2.0 mg·kg^(-1)·d^(-1)和20.0 mg·kg^(-1)·d^(-1))与CUMS刺激单独或联合暴露21 d后,雄性C57BL/6J小鼠肝脏中氨基酸代谢、TCA循环和胆汁酸代谢的变化.研究发现,2.0 mg·kg^(-1)·d^(-1)B[a]P可使小鼠肝脏中精氨琥珀酸、精氨酸和丙氨酸显著升高,谷氨酰胺显著降低;20.0 mg·kg^(-1)·d^(-1)B[a]P则主要导致丙氨酸显著上升,谷氨酰胺下降.慢性压力应激使小鼠肝脏同型半胱氨酸的含量显著下降. B[a]P与慢性压力应激同时暴露时,小鼠肝脏氨基酸和胆汁酸代谢会发生显著变化.进一步采用代谢扰乱度(metabolic effect level index,MELI)评估了两个风险因子的联合作用效果,发现2.0 mg·kg^(-1)·d^(-1)B[a]P和慢性压力应激同时暴露对小鼠氨基酸代谢、TCA循环和胆汁酸代谢的影响分别为拮抗、协同和加和作用;而20 mg·kg^(-1)·d^(-1) B[a]P和慢性压力应激同时暴露的小鼠氨基酸代谢和胆汁酸代谢的影响均为加和作用,TCA循环为拮抗作用.结果表明,不同剂量的B[a]P和CUMS暴露造成小鼠肝脏氨基酸代谢和胆汁酸代谢紊乱,差异的代谢物与两者单独暴露时明显不同,且代谢的变化与B[a]P暴露剂量密切相关.

Combined effect of tributyltin and benzo[a] pyrene on the levels of sex hormone and vitellogenin in female Sebastiscus marmoratu

Tributyltin（TBT）, an organometal used as an antifouling biocide, has been reported to induce masculinization of fish. Benzo [a]pyrene （BaP）, a widespread carcinogenic polycyclic aromatic hydrocarbon, has been reported that its microsomal metabolites can produce an estrogenic response when tested in vitro. This study was therefore designed to examine the potential in vivo influence of TBT, BaP and their mixture on sex hormone levels in serum of Sebastiscus marmoratus, which were given 2 separate intraperitoneally （ip） injections（a single injection every 7 d） of TBT（0.5, 1, 5 and 10 mg/kg）, BaP（0.5, 1, 5 and 10 mg/kg）, or both in combination（0.5, 1, 5 and 10 mg/kg）; control fish received olive oil vehicle only. Six days after the 2nd injection, serum samples were collected and analyzed for sex hormone levels and alkali labile protein phosphorus （ALPP）, which is related to the yolk precursor protein vitellogenin. The pollutants at all doses significantly reduced serum testosterone, estradiol and ALPP content after 2 injections compared with the corresponding controls. The reduction of the estradiol levels should be response for the decrease of the vitellogenin levels. The results in the present study suggested that aromatase seems not the major target acted by TBT and BaP in fish. This study demonstrated that TBT or BaP exposure both inhibit the reproductive potential in female Sebastiscus marmoratus. Combined effect of TBT and BaP on the serum testosterone, estradiol and ALPP was not antagonism from the anticipation.

苯并[a]芘对生殖系统的毒性作用及其机制研究进展

苯并[a]芘(benzo(a)pyrene,BaP)作为多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的成员,是最早发现也是最具有代表性的环境污染物,通过空气、食物、水源等途径进入人体,引起细胞氧化应激损伤、DNA损伤和基因异常表达导致细胞死亡。研究表明雄性与雌性动物经BaP染毒后,其生殖器官、生殖细胞甚至激素水平均会受到影响,进而影响受精卵形成和胚胎发育,造成不良妊娠结局。因此,近年来BaP的生殖毒性受到广泛关注,其作用机制包括改变胞内活性氧水平、诱导细胞DNA损伤以及调控生殖发育相关基因、类固醇合成相关基因和促凋亡基因影响生殖发育。BaP作为环境毒物,不仅可以影响生态环境的稳定性,还可以影响生物的生殖发育,损害生态环境中的物种多样性,从长远来看,BaP的不良影响不但会威胁到陆地与海洋生物种群的稳定,还会破坏陆地和海洋生态系统的功能。本文将从生殖健康、配子与合子形成以及胚胎发育的角度,详细阐述BaP染毒对生殖系统的毒性作用与机制,为预防BaP引起的生殖危害、减少不良妊娠结局提供理论依据,旨在为BaP的环境毒性行为和对生物的毒性研究提供有效借鉴,为合理预防和缓解因接触BaP等环境毒物而带来的健康影响提供参考。

EROD activities of liver in Mugil so-iuy exposed to benzo(a)pyrene,pyrene and their mixture

The effects on hepatic EROD (7-ethoxyresorufin O-deethylase) in Mugil so-iuy exposedto benzo(a)pyrene (BaP), pyrene and their mixtures of equal concentration were investigated, at concentrations of 0.1, 1.0, 5.0, 10.0, 50.0μg/dm3, in experimental condition. Time-effects and dose-response of the biochemical indexs were observed. The results showed that the hepatic EROD activities were induced by the exposure of BaP, pyrene and their mixtures at high concentration. Dose-response connections were that the hepatic EROD activities were elevated with increasing concentration of the pollutants. The combined effect of BaP and pyrene at 1:1 concentration ratio on hepatic EROD activity was antagonism.

活化过硫酸钠处理苯并[a]芘污染土壤的应用研究

为了研究异位化学氧化技术对苯并[a]芘污染土壤的修复效果,在实验室开展模拟化学氧化烧杯试验,对比测试了Fe^(2+)、生石灰及过氧化氢等药剂活化过硫酸钠的处理效果,试验结果发现生石灰活化表现出最好的修复效果,其次是亚铁盐活化。选用生石灰活化和硫酸亚铁活化的方式开展中试,结果表明生石灰活化的修复效果更优,并且确定过硫酸钠的投加量为土壤质量的1.0%。最后开展了约280 t污染土壤的工程应用,达到了修复目标。通过成本分析得知,生石灰活化的方式更经济。

Effects of benzo(a)pyrene exposure on the antioxidant enzyme activity of scallop Chlamys farreri

Scallop Chlamys farreri was exposed to different concentrations of benzo(a)pyrene (BaP) (0.5 μg/L, 1.0 μg/L, 10.0 μg/L and 50.0 μg/L) for 30 days in seawater. The 7-ethoxyresorufin O-deethylase (EROD) activity was significantly induced, and increased with the increasing BaP concentration. The glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), Glutathione peroxidase (GPx) activities increased in short time at low concentration of BaP, and was significantly depressed at high concentrations. Scallop gill was more sensitive to BaP than the digestive gland, and the digestive gland was the main tissue to deal with oxyradicals. The contents of malondialdehyde (MDA) increased with the exposure time and there was a positive correlation (concentration-effect) between the MDA content and the concentration of BaP. The biomarkers determined in this experiment had important roles in detoxification, and showed great potential as biomarkers for oxidative stress. Controlled laboratory experiments designed to simulate field exposure scenarios are particularly useful in ascertaining biomarkers suitable for use with complex contaminant mixtures in the marine environment.

短链脂肪酸对苯并[a]芘致小鼠认知功能障碍的影响

目的 观察短链脂肪酸(short-chain fatty acids, SCFAs)对苯并[a]芘(benzo[a]pyrene, B[a]P)慢性染毒小鼠的认知功能、大脑皮质和结肠的影响,并探讨其作用机制。方法 将30只8周ICR雄性小鼠随机分为对照组、B[a]P组和B[a]P+SCFAs组,每组10只。B[a]P组以10.0 mg/kg剂量隔天定时灌胃染毒,共45次,对照组灌胃等体积的花生油,两组均自由饮用纯净水。B[a]P+SCFAs组在10.0 mg/kg B[a]P染毒同时,其饮用水为SCFAs混合液(67.5 mmol/L乙酸钠、40 mmol/L丁酸钠和25.9 mmol/L丙酸钠)。染毒结束,采用T迷宫、新位置识别实验、洞板实验和爬杆实验检测小鼠认知功能改变。HE法观察皮质、结肠病理改变;ELISA法测定皮质和结肠中炎症因子IL-1β和TNF-α表达水平;RT-PCR法和Western blot法分别检测结肠紧密连接蛋白ZO-1和Occludin的mRNA和蛋白表达水平。结果 与对照组相比,B[a]P组小鼠空间记忆力、运动能力减弱,焦虑样反应增加(P<0.05),提示小鼠认知功能障碍发生;同时,小鼠大脑出现大量红色神经元,肠道细胞排列紊乱,肠绒毛断裂不全且间隔稀疏,杯状细胞明显减少且分布不均;皮质和结肠中IL-1β含量均显著增加(P<0.05),TNF-α表达呈上升趋势但无统计学意义(P>0.05);结肠ZO-1、Occludin mRNA和蛋白表达水平均显著降低(P<0.05)。与B[a]P组比较,B[a]P+SCFAs组小鼠空间记忆力、运动能力增强,焦虑样反应显著降低(P<0.05),提示SCFAs干预显著改善B[a]P所致的小鼠认知功能障碍。同时,SCFAs干预显著减少大脑红色神经元,结肠杯状细胞数量有所恢复,并显著降低小鼠皮质和结肠中IL-1β、皮质中TNF-α的含量(P<0.05),结肠ZO-1、Occludin mRNA和蛋白表达水平均显著升高(P<0.05)。结论 SCFAs干预能有效改善B[a]P诱导的小鼠认知功能障碍,可能与其增加结肠紧密连接蛋白mRNA和蛋白的表达,降低肠道通透性,促进肠道屏障修复进而减轻肠道和神经炎症有关。