苯并[a]芘对小鼠的神经毒性及脑组织热应激蛋白水平的影响

目的　研究苯并 [a]芘 (BaP)对小鼠的神经毒性及对脑组织热应激蛋白HSP70、HSP90 β表达的影响。 方法　将 5 0只昆明种小鼠随机分为 5组 ,每组 10只 ,染毒组分为高、中、低 3个剂量 ,并设溶剂对照及空白对照组。染毒组用BaP的植物油溶剂进行腹腔注射处理 ,高、中、低剂量组每次分别注射 7 8、3 2和 1.3mg kgBW ,每周 4次。溶剂对照组用植物油溶剂作平行处理 ,空白对照组不做处理。实验中观察一般情况及神经系统表现 ,实验 8周后取各组小鼠全脑组织 ,观察、称量并计算脑组织脏器系数 ,Westernblot法检测HSP70、HSP90 β水平。结果　①中、高剂量BaP染毒组小鼠脑组织重明显低于对照组 ,高剂量BaP染毒组小鼠脑组织脏器系数明显低于其他组。②HSP70表达改变以低剂量BaP染毒组相对表达值明显增高为特征 ;HSP90 β表达改变为中、高剂量BaP染毒组相对表达值升高。结论　BaP具有一定的神经毒性。随着染毒剂量增加 ,HSP90 β表达水平增高。     

Response of integrated biomarkers of fish (Lateolabrax japonicus) exposed to benzo[a]pyrene and sodium dodecylbenzene sulfonate

Fish Lateolabrax japonicus were exposed to 0.1 and 1mg/L of anion surfactant sodium dodecylbenzene sulfonate (SDBS) and to 2 and 20 microg/L of benzo[a]pyrene (B[a]P) for 6, 12, and 18 days, with control and solvent control groups. Liver antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), and glutathione S-transferase (GST), were determined; brain acetylcholinesterase (AChE) and liver inducible nitric oxide synthase (iNOS) activities were also measured. The results indicated that (1) L. japonicus avoided oxidative damage through antioxidant systems; (2) SOD, GPx, and GSH were induced, and GST was inhibited and then induced by B[a]P exposure; and (3) CAT, GPx, and AChE were induced while iNOS was inhibited, and GST was induced and then inhibited by SDBS stress in experimental period.     

孕期暴露苯并[a]芘对子代大鼠神经发育毒性的影响

目的 研究孕期暴露苯并(a)芘(B[a]P)对子代大鼠生理发育、早期行为发育、对环境的适应能力及学习记忆能力的影响.方法 SD孕鼠随机分为未处理对照组(每日正常饲养)、溶剂对照组(橄榄油)、低剂量组(25mg/kgB[a]P)、中剂量组(50mg/kgB[a]P)、高剂量组(100mg/kg B[a]P),于妊娠第17天开始,每天1次腹腔注射染毒,连续3 d,待其自然分娩.仔鼠出生后第1、4、7、14、28天称量体重,检测仔鼠生理发育、运动反射及感觉功能等发育指标,用Morris水迷宫试验和旷场试验分别评价仔鼠的学习记忆能力和对新异环境的适应能力.结果 与未处理对照组[(3.3±0.5)d]和溶剂对照组[(3.4±0.6)d]比较,中、高剂量组仔鼠张耳时间[(4.1±0.4)、(5.0±0.4)d]延长,差异有统计学意义(P＜0.01).与未处理对照组(36、1%)相比,第4天高剂量组平面翻正试验达标率(6.5%)明显降低,与未处理对照组和溶剂对照组(81.3%、79.3%)相比,第7天时高剂量组仔鼠平面翻正试验达标率(50.0%)明显降低,差异有统计学意义(P＜0.05).与未处理对照组比较,第12、14天时各染毒组仔鼠前肢悬挂时间均减少;与溶剂对照组比较,第14天时高剂量组仔鼠前肢悬挂时间减少,差异有统计学意义(P＜0.01).与未处理对照组(94.3%)相比,第12天时高剂量组仔鼠嗅觉定向试验达标率(61.9%)明显降低,差异有统计学意义(P＜0.05).Morris水迷宫试验结果表明,与未处理对照组和溶剂对照组比较,各剂量组仔鼠逃避潜伏期明显增加,高剂量组在目标象限停留时间和穿越平台次数减少,差异均有统计学意义(P＜0.01).旷场实验结果表明,与未处理对照组[(2.40±0.89)、(82.2±15.9)、(17.4±3.9)s]比较,中、高剂量组仔鼠中央格停留时间[(9.67±1.53)、(12.80±3.77)s]明显延长,跨格次数(51.3±8.7、49.4±20.0)明显减少,高剂量组直立次数(8.0±2.6)明显减少,差异均有统计学意义(P＜0.05);与溶剂对照组相比,各剂量组跨格次数明显减少,差异均有统计学意义(P＜0.01,P＜0.05).结论 孕期暴露B[a]P对仔鼠的生理发育、早期行为发育产生一定的抑制作用,并对仔鼠大脑学习记忆能力及其对新异环境的适应能力有一定影响.

Abstract：

Objective To study the effects of prenatal exposure to benzo[a]pyrene (B[a]P) on the physical development, early behavioral development, the adaptability to new environment and the learning and memory ability of rat offspring. Methods Pregnant rats were randomly divided into five groups: control group,olive oil group, 3 exposure groups (25, 50 and 100 mg/kg B [a]P). The rats were exposed to B [a]P) by intraperitoneal injection on the 17th-19th days during gestation. The offspring were weighed on postnatal days (PND)1, PND 4, PND 7 and PND 28, the indices of physical development, reflective ability and sensory function were detected for offspring, the Morris water maze and Open-field tests were used to measure the ability of learning and memory and the adaptability to new environment of offspring. Results The time of ear opening in middle and high-dose groups[(4. 1 ±0.4),(5.0±0.4) d] was posterior to that in untreated and solvent groups[(3.3±0.5),(3.4±0.6) d](P＜0.01).The attainment rate (6.5%) of the surface righting reflex test in highdose group on the 4th day was significantly lower than that (36.1%) in untreated group, the attainment rate(50.0%) in high-dose group on PND7 was significantly lower than those (81.3% and 79.3%) in untreated group and solvent group (P＜0.05). Compared to the untreated group, the time of forelimb hanging test in all exposure groups on PND12 and PND14 significantly decreased; compared to the solvent group the time of forelimb hanging test decreased in high-dose group on the 14th day significantly decreased (P＜0.01). The attainment rate (61.9%) of olfactory discrimination in high-dose group on PND 12 was significantly lower than that (94.3%) in untreated group (P＜0.05). The results of morris water maze test showed that the escape latency of different dose groups significantly increased, and the time of spatial probe and the times of traversing flat in high-dose group decreased significantly, as compared to the untreated and solvent groups(P＜0.01). The results of open-field test indicated that the center retention time in middle and high-dose groups significantly prolonged, the times of crossing lattice obviously reduced, and the rearing times decreased in high-dose group,as compared to untreated(P＜0.05).Compared to the solvent group, the times of crossing lattice in all exposure groups reduced significantly(P＜0.01 or P＜0.05). Conclusion The prenatal exposure to B[a]P could inhibit the physical development and early behavioral development, and influence the adaptability to new environment and learning and memory ability for offspring.     

孕期暴露苯并[a]芘对子代大鼠神经发育毒性的影响

Objective To study the effects of prenatal exposure to benzo[a]pyrene (B[a]P) on the physical development, early behavioral development, the adaptability to new environment and the learning and memory ability of rat offspring. Methods Pregnant rats were randomly divided into five groups: control group,olive oil group, 3 exposure groups (25, 50 and 100 mg/kg B [a]P). The rats were exposed to B [a]P) by intraperitoneal injection on the 17th-19th days during gestation. The offspring were weighed on postnatal days (PND)1, PND 4, PND 7 and PND 28, the indices of physical development, reflective ability and sensory function were detected for offspring, the Morris water maze and Open-field tests were used to measure the ability of learning and memory and the adaptability to new environment of offspring. Results The time of ear opening in middle and high-dose groups[(4. 1 ±0.4),(5.0±0.4) d] was posterior to that in untreated and solvent groups[(3.3±0.5),(3.4±0.6) d](P＜0.01).The attainment rate (6.5%) of the surface righting reflex test in highdose group on the 4th day was significantly lower than that (36.1%) in untreated group, the attainment rate(50.0%) in high-dose group on PND7 was significantly lower than those (81.3% and 79.3%) in untreated group and solvent group (P＜0.05). Compared to the untreated group, the time of forelimb hanging test in all exposure groups on PND12 and PND14 significantly decreased; compared to the solvent group the time of forelimb hanging test decreased in high-dose group on the 14th day significantly decreased (P＜0.01). The attainment rate (61.9%) of olfactory discrimination in high-dose group on PND 12 was significantly lower than that (94.3%) in untreated group (P＜0.05). The results of morris water maze test showed that the escape latency of different dose groups significantly increased, and the time of spatial probe and the times of traversing flat in high-dose group decreased significantly, as compared to the untreated and solvent groups(P＜0.01). The results of open-field test indicated that the center retention time in middle and high-dose groups significantly prolonged, the times of crossing lattice obviously reduced, and the rearing times decreased in high-dose group,as compared to untreated(P＜0.05).Compared to the solvent group, the times of crossing lattice in all exposure groups reduced significantly(P＜0.01 or P＜0.05). Conclusion The prenatal exposure to B[a]P could inhibit the physical development and early behavioral development, and influence the adaptability to new environment and learning and memory ability for offspring.     

Determinants of benzo[a]pyrene diol epoxide adducts to albumin in workers exposed to polycyclic aromatic hydrocarbons

The present study was undertaken among 260 subjects [133 controls and 127 persons exposed to polycyclic aromatic hydrocarbons (PAHs)] from two steel foundries and a graphite electrode producing plant in order to investigate the relationship between the benzo[a]-pyrene-diol epoxide adducts to albumin (BPDE-alb) and the intensity of exposure to PAHs. Blood samples were collected from each subject and BPDE-alb adduct determination was performed using a high-pressure liquid chromatography technique with fluorescence detection. Exposure to PAHs was assessed by measuring airborne concentration of 13 PAHs including benzo[a]pyrene (BaP) using personal air sampling and 1-hydroxypyrene excretion (1-HOP) in postshift urine. Significantly higher BPDE-alb adduct levels were observed in exposed workers compared to controls but wide interindividual variation was observed between subjects with the same level of exposure. BPDE-alb adduct level was weakly but significantly associated with the airborne concentrations of total PAHs (r = 0.35, P = 0.0001) and BaP (r = 0.30, P = 0.0001), and urinary 1-HOP excretion (r = 0.29, P = 0.0001). Alcohol and dietary habits, place of residence, and renal and hepatic status were not found to influence the concentration of BPDE-alb adducts significantly. However, for the same level of exposure to BaP, smokers had a higher probability of having an elevated BPDE-alb adduct level than nonsmokers. As long as BPDE-protein adduct levels have not been demonstrated to be better related to the risk of adverse genotoxic effects caused by PAHs in target organs than the 1-HOP level in urine, the latter remains the most practical biological parameter for assessing the risk of exposure to PAHs.     

Evaluation of biomarkers of exposure and effect in juvenile areolated grouper (Epinephelus areolatus) on foodborne exposure to benzo[a]pyrene

Food-borne benzo[a]pyrene (B[a]P) was administered daily to juvenile grouper (Epinephelus areolatus) at two environmentally realistic concentrations (a low dose of 0.25 microg B[a]P/g body wt/d and a high dose of 12.5 microg B[a]P/g body wt/d) to investigate and relate temporal changes in body burden of B[a]P, hepatic ethoxyresorufin-O-deethylase (EROD) activities, growth, RNA:DNA ratio, estradiol, testosterone, and triiodothyronine (T3). After feeding with B[a]P diets for four weeks, fish were fed with normal diet for another four weeks to study recovery of the various biomarkers during the depuration period. After one week of exposure, both body muscle B[a]P burdens and hepatic EROD activities significantly increased. Body burdens were stable in tissues until the fourth week of exposure, when concentrations in the high-dose group increased markedly, at which time a concomitant decrease in EROD was found. During the depuration period, body burdens decreased in the second week, and EROD declined in the first week. Growth and RNA:DNA ratio were unaltered. Despite large variations found in sex steroid levels, elevation of testosterone was clearly evident in the fourth week, showing that B[a]P may disrupt the balance of sex steroids in fish. Significantly, increases in plasma-free T3 concentrations were found in the fourth week of exposure and the first week of depuration, suggesting that development and reproduction may potentially be at risk during chronic exposures. Our data also suggest that these hormonal disturbances are not persistent and that normal hormonal levels can be restored soon after contamination is abated.     

Induction and localization of hepatic CYP4501A in flounder and rainbow trout exposed to benzo[a]pyrene

The hepatic detoxification system in Baltic flounder and rainbow trout was characterized under experimental conditions. Fish were exposed to benzo[a]pyrene (BaP, 10 and 50mg/kg, ip) or vehicle for 2, 5, and 10 days (in rainbow trout also for 20 days) and then sacrificed. Control fish were sampled at days 0 and 10 (flounder) or day 20 (rainbow trout). The hepatic distribution of CYP1A was analyzed immunohistochemically and microsomal ethoxyresorufin O-deethylase activity was determined spectrophotometrically. The kinetics of the CYP1A responses (EROD) was similar in both species, while a species-specific difference in the magnitude of the response was observed. CYP1A was demonstrated in the hepatocytes in both fish species 2 days after BaP administration and throughout the experiment. In rainbow trout a CYP1A response in the vascular endothelium of liver parenchyma was detected 2 days postadministration, while the corresponding reaction in flounder was seen 5 days postadministration. Thus, our results confirm previous reports that the CYP1A response is species specific. Furthermore, the induction of hepatic CYP1A in Baltic flounder reflects pathophysiological effects induced by polycyclic aromatic hydrocarbon compounds and, consequently, is a parameter useful when monitoring the anthropogenic effects on the Baltic Sea environment.     

苯并[a]芘染毒小鼠神经组织的形态学改变及细胞凋亡

目的：研究苯并[а]芘(BaP)染毒小鼠神经组织的损伤状况。方法：将50只昆明种小鼠随机分为5组，每组10只，染毒组分为高、中、低3个剂量组，并设溶剂对照及空白对照组。染毒组用含BaP的植物油溶剂进行腹腔注射，每组分别注射7.8、3.2和1.3mg/kg，每周4次，连续染毒10周。溶剂对照用植物油溶剂作平行处理，空白对照组不做处理。10周后取各组小鼠脑组织大脑皮质、海马、小脑和脑干部分以及脊髓、坐骨神经制作普通石蜡切片及电镜切片，光镜及电镜观察组织损伤的形态学指标，并用DNA断点末端核糖核酸转移酶地高辛标记（TUNEI）法进行细胞原位凋亡检测。结果：BaP染毒组在光镜及电镜下可见到组织损伤的形态学改变，高剂量组各组织在光镜及电镜下可见较为集中的坏死区，未做原位凋亡检测；中剂量组原位细胞凋亡阳性率为90.02%-94.22%；低剂量组原位细胞凋亡阳性率为62.45%-77.54%；而溶剂对照及空白对照组各组织未见组织损伤，原位细胞凋亡阳性率很低（4.60%-5.57%）。结论：BaP具有神经毒性，可损伤神经组织并使神经细胞胞核内DNA断裂，引起神经细胞凋亡。     

The effects of intramuscular and intraperitoneal injections of benzo[a]pyrene on selected biomarkers in Clarias gariepinus

This study investigated the dose-dependent and time-course effects of intramuscular (i.m.) and intraperitoneal (i.p.) injection of benzo[a]pyrene (BaP) on the biomarkers EROD activity, GST activity, concentrations of BaP metabolites in bile, and visceral fat deposits (Lipid Somatic Index, LSI) in African catfish (Clarias gariepinus). Intraperitoneal injection resulted in 4.5 times higher accumulation of total selected biliary FACs than i.m. injection. Hepatic GST activities were inhibited by BaP via both injection methods. Dose-response relationships between BaP injection and both biliary FAC concentrations and hepatic GST activities were linear in the i.p. injected group but nonlinear in the i.m. injected fish. Hepatic EROD activity and LSI were not significantly affected by BaP exposure by either injection route. We conclude that i.p. is a more effective route of exposure than i.m. for future ecotoxicological studies of PAH exposure in C. gariepinus.     

DNA adduct formation of benzo[a]pyrene in white blood cells of workers exposed to polycyclic aromatic hydrocarbons

The major DNA adducts of anti-benzo[a]pyrene diolepoxide (BPDE) were determined by high performance liquid chromatography with fluorescence detection (HPLC-FLD) in white blood cells (WBC) of workers exposed to benzo[a]pyrene (B[a]P). In addition, ambient concentrations of B[a]P at the workplace were determined by personal air sampling. Workers in a refractory setting were examined before (n=26) and 3 months after (n = 33) changing the production material (binding pitch). Furthermore, 9 coke oven workers were examined. The change in the production process in the refractory setting led to a decrease in the median of ambient B[a]P concentrations (0.14 to <0.07 microg/m3). The median of BPDE-DNA adduct levels in WBC also decreased from 0.9 adducts/10(8) nucleotides before changing the production material to <0.5 adducts/10(8) nucleotides 3 months afterwards. The B[a]P concentrations at the workplace for the coke oven workers were found to be significantly higher than in the refractory setting. However, BPDE-DNA adduct concentrations in coke oven workers and refractory setting workers showed no significant difference, which was probably due to the low number of studied subjects in the coke-oven setting. No significant differences could be observed for BPDE-DNA adduct levels between current smokers (n=21) and non-smokers (n=14; p = 0.93) from both plants. In addition, no correlation between B[a]P concentrations in the air and DNA adduct levels in refractory workers and in coke oven workers could be found (r = -0.03, p = 0.87). Because of the missing correlation between personal air sampling and BPDE-DNA adduct levels in WBC, the results may indicate that their formation is either influenced by other routes of exposure to B[a]P (e.g., skin absorption, dietary habits) or interindividual differences in their formation and repair.     

苯并[a]芘在大鼠脑组织中分布动态观察

目的 观察[¹⁴C]标记苯并[a]芘在大鼠脑内的分布。方法 将100只SD大鼠随机分为对照组和实验组,实验组尾静脉注射[¹⁴C]标记苯并[a]芘3.7×10⁵Bq/kg,对照组注射等量生理盐水;在注射后1,6,12,24和48 h用光镜放射自显影法观察苯并[a]芘在脑内的分布情况。结果 与对照组比较,实验组大鼠脑组织注药后1 h即有苯并[a]芘银粒出现,随着时间的增加,银粒数也逐渐增加,24 h达高峰,48 h明显减少,注射后1,6,12,24,48 h银粒数分别为(17.68±1.79),(22.67±2.15),(25.79±2.55),(32.33±2.78),(18.01±1.68)粒,差异有统计学意义(F=69.67,P<0.01);银粒在脑中分布不均匀,注药后1 h主要集中在海马,6 h主要集中于大脑皮层,12 h则分布于纹状体;各时相脑组织中神经元银粒数明显高于神经胶质细胞(P<0.05)。结论 苯并[a]芘在各脑区的分布不均匀,24 h达到高峰,神经元细胞可能是苯并[a]芘靶细胞。     

Anguilla anguilla L. biochemical and genotoxic responses to benzo[a]pyrene

Eels (Anguilla anguilla L.) were exposed for 2, 4, 6, 8, 16, 24, 48, 72, 144, and 216 h to 0 (control), 0.3, 0.9, and 2.7 microM benzo[a]pyrene (BaP). The biotransformation induced by BaP was measured as liver ethoxyresorufin O-deethylase (EROD) activity and cytochrome P450 content, and compared with the genotoxic effects, such as erythrocytic nuclear abnormalities (ENA), and blood and liver DNA strand breaks. The liver exhibited a highly significant EROD activity increase from 2 up to 216 h exposure to 0.9 and 2.7 microM BaP, whereas 0.3 microM BaP exposure induced a significant liver EROD increase from 2 up to 144 h. Liver cytochrome P-450 content was significantly increased at 8 h to 2.7 microM BaP exposure. Liver DNA integrity was decreased at 16 h, from 8 up to 144 h and 8 up to 72 h exposure to 0.3, 0.9, and 2.7 microM BaP, respectively. A significant decrease in blood DNA integrity was observed at 48, 72, 144 h, from 8 up to 72, and from 6 up to 72 h exposure to 0.3, 0.9, and 2.7 microM BaP, respectively. The A. anguilla L. genotoxic response to BaP, measured as ENA induction, was significantly increased at 144 h exposure to 0.3 microM BaP. The intermediate BaP concentration tested (0.9 microM) induced a significant three fold ENA increase at 48 and 72 h exposure compared to their controls. The highest BaP concentration (2.7 microM) induced a significant increase in ENA frequency at 72, 144 and 216 h exposure.     

双壳类水产品中(+)-anti-BPDE-DNA加合物HPLC/FD检测

目的 建立检测双壳类水产品中（+）-反-7,8-二羟基-9,10-环氧苯并（a）芘（BPDE）-DNA加合物的高效液相色谱荧光法（HPLC/FD）。方法 用组织基因组DNA提取试剂盒提取6种双壳类水产品组织中的DNA,0.1 mol/L HCl 、90 ℃酸解4 h,乙酸乙酯充分萃取酸解产物——苯并（a）芘-四醇。以CenturySIL C18-BDS色谱柱（150 mm×4.6 mm,5 μm）分离;洗脱流动相：V（甲醇）/V（水）=55/45;流速：1.0 mL/min;进样量：20 μL;激发波长：265 nm,发射波长：395 nm;荧光检测苯并（a）芘-四醇的含量。结果 该方法的检测限为0.3 ng/mL,在0.5~100 ng/mL范围内呈良好的线性关系（r²=0.9960）;日内相对标准偏差（RSD）为2.8%~4.2%,日间RSD为3.2%~5.8%;双壳类水产品中（+）-anti-BPDE-DNA含量为13.44~152.7 μg/kg,RSD为3.0%~6.5%;加标回收率为86.9%~91.6%,RSD为3.1%~7.3%。结论 该法简便、快速、灵敏度高,可用于双壳类水产品中（+）-anti-BPDE-DNA加合物的检测。     

亚慢性染毒苯并[a]芘对大鼠海马热休克蛋白70表达的影响

目的 研究亚慢性染毒苯并[a]芘(B[a]P)对大鼠海马热休克蛋白70( Hsp70)的影响。方法 选择48只健康雄性SD大鼠,饲养1周后将动物随机分为空白对照组、溶剂对照组及0.5、1.5、4.5、10.0 mg/kg B[a]P染毒组,隔日腹腔注射染毒90d,Morris水迷宫试验进行行为学测试。免疫印迹(Westem-blot)法和反转录-聚合酶链反应(RT-PCR)法分别检测大鼠海马Hsp70蛋白和Hsp70 mRNA的表达水平,免疫组织化学法观察大鼠海马各区Hsp70表达情况,图像分析系统测定Hsp70平均灰度值。结果 Morris水迷宫结果显示,4.5、10.0 mg/kg B[a]P组大鼠平均潜伏期和平均总路程明显高于空白对照组、溶剂对照组、0.5、1.5 mg/kg B[a]P组,差异有统计学意义(P＜0.05);10.0 mg/kg B[a]P组平台象限滞留时间明显低于空白对照组、溶剂对照组和0.5mg/kg B[a]P组,差异有统计学意义(P＜0.05)。B[a]P染毒组大鼠海马hsp70蛋白和hsp70 mRNA的表达水平均随染毒剂量增高而下降。其中,4.5、10.0 mg/kgB[a]P组Hsp70蛋白表达水平明显低于空白对照组、溶剂对照组和0.5mg/kg B[a]P组,差异有统计学意义( P＜0.01,P＜O.05);0.5、4.5、10.0 mg/kg B[a]P组hsp70 mRNA表达水平明显低于空白对照组、溶剂对照组,差异有统计学意义(P＜0.01),10.0 mg/kg B[a]P组hsp70 mRNA表达水平明显低于其他染毒组。免疫组化结果显示,海马CA1、CA2、CA3、DG区Hsp70表达平均灰度值均随着B[a]P染毒剂量的增高而呈下降趋势。Pearson相关性分析结果显示,大鼠海马Hsp70表达水平与平均潜伏期呈负相关（r=-0.428,P＜O.05）;大鼠海马hsp70 mRNA表达水平与平均潜伏期、平均总路程呈负相关(r值分别为-0.677、-0.594,P＜0.01),与平台象限滞留时间呈明显正相关(r=0.597,P＜O.01)。结论 亚慢性染毒B[a]P可抑制大鼠海马Hsp70的表达,与大鼠学习记忆和空间探索能力损害相关,该抑制作用无区域特异性。     

Factors affecting plasma benzo[a]pyrene levels in environmental studies

Benzo[a]pyrene (BaP) is a useful indicator of exposure to polycyclic aromatic hydrocarbons (PAHs), airborne carcinogenic compounds. Radioimmunoassay was used to test for plasma BaP differences in 61 subjects divided into three groups based on geographic-demographic locale: urban-industrial, urban-residential, and outer suburban. The results showed that the urban-industrial area participants had a significantly higher mean plasma BaP level than did the outer suburban subjects. The urban-residential subjects did not have a significantly different mean plasma benzo[a]pyrene level from either of the other two groups. Obesity, as measured by Quetelet's index, was found to have a significant correlation with BaP levels. These results indicate that radioimmunoassay of plasma for BaP may be used successfully to judge environmental exposure to PAHs, provided physiological considerations such as obesity are taken into account.     

Oxygen consumption rates of grunion (Leuresthes tenuis) embryos exposed to the petroleum hydrocarbon, benzo[a]pyrene

Bioconcentration of [14C]benzo[a]pyrene and effects of unlabeled benzo[a]pyrene (BaP) accumulation on the routine oxygen consumption of embryonic grunion (Leuresthes tenuis) were studied. At Day 15, bioconcentration factors over dissolved BaP levels ranged from 249 to 466. Weight-specific respiration rates at Days 14-15 were significantly increased (P less than or equal to 0.05) at a mean BaP body burden of 0.51 ppm wet wt. Oxygen consumption rates of embryos containing 0.70 to 12.80 ppm BaP were not significantly different from control rates. Because in a previous study embryos containing 0.51 ppm BaP exhibited hatching and developmental rates similar to those of controls, their metabolic response to low-level hydrocarbon exposure may be an example of hormesis, an overcompensating metabolic regulation to inhibitory challenges.     

Chemical and biological availability of sediment-sorbed benzo[a]pyrene and hexachlorobiphenyl

This study examined the chemical and biological availability of two nonpolar organic compounds, benzo[a]pyrene (BaP) and hexachlorobiphenyl (HCBP), from a spiked sediment that was aged for varying amounts of time. Chemical availability was evaluated using four different solvent combinations to extract chemicals from the sediment. The extractability of BaP and HCBP from sediment using traditional solvents was then compared to the transfer efficiency (TE) of a benthic invertebrate (Lumbriculus variegatus) to relate chemical extractability to bioavailability in the organisms. Results indicated that water was the solvent that best approximated bioavailability for BaP, whereas comparisons for HCBP were inappropriate, because TE values exceeded 100%. The inability to obtain a reasonable TE estimate for HCBP was most likely due to the fact that the oligochaetes received a major portion of their uptake from interstitial water instead of ingestion of sediment particles, which invalidated an important assumption of the TE model. Overall, the results of this study indicate that exhaustive chemical extractions may be an inaccurate representation of the bioavailable fractions for some contaminants.     

苯并[a]芘与铅联合神经毒性的细胞学研究

目的苯并[a]芘(BaP)、铅及其联合作用对体外神经元的毒性及细胞凋亡率的影响.方法取8日龄SD大鼠小脑粒细胞培养,按以下分组进行处理空白对照组;溶剂对照组;低浓度铅染毒组;高浓度铅染毒组;低浓度BaP染毒组;高浓度BaP染毒组;低浓度铅+低浓度BaP染毒组;低浓度铅+高浓度BaP染毒组;高浓度铅+低浓度BaP染毒组;高浓度铅+高浓度BaP染毒组;高、低浓度的BaP染毒分别为BaP50μmol/L+S9-mix和BaP5μmol/L+S9-mix,高、低浓度的铅染毒分别为50和5μmol/L的PbAc,溶剂对照组用等量DMSO平行处理,空白对照组不作处理.染毒90min,胰酶消化法收集标本.台盼蓝染色法检测存活率;DNA断点末端核糖核酸转移酶地高辛标记(TUNEL)法检测大鼠小脑粒细胞凋亡率,并对细胞存活率与凋亡率进行相关分析.结果各染毒组细胞存活率均低于对照组,高剂量组降低程度高于低剂量组,联合染毒组降低程度高于单独染毒组(P<0.05～P＜10E-7).各染毒组细胞凋亡率显著升高,高剂量组升高程度高于低剂量组,联合染毒组升高程度高于单独染毒组(P＜0.001～P＜10E-9).细胞凋亡率与存活率间呈负相关(r=-0.76125,P＜0.05).结论 BaP、铅均有一定的体外神经毒性,二者联合作用可使毒性增强.细胞凋亡可能是BaP引起体外神经毒性的机制之一.