Effects of benzo(a)pyrene on early development of flatfish

The ontogenetic effects of the environmental carcinogen benzo(a)pyrene (BAP) on three species of larval flatfish were investigated using concentrations (from 0.10 to 4.2 ppb) which were comparable to levels found in polluted harbors. BAP-treated sand sole (Psettichthys melanostichus) eggs displayed a significant decline in hatching success and a significantly higher incidence of developmental anomalies than did control eggs. Flathead sole (Hippoglossoides elassodon) eggs exposed to a single dose of a water-soluble BAP-bovine serum albumin complex demonstrated evidence of toxie injury with pycnotic nuclei present in the integument and, more commonly, in ocular and neural tissues. An increased incidence of morphological anomalies in English sole (Parophyrs vetulus) eggs and larvae exposed to BAP was not detected.     

Wheat bran and the induction of intestinal benzo(a)pyrene hydroxylase by dietary benzo(a)pyrene

The mucosa of the intestine responds to polycyclic aromatic hydrocarbons (PAH) with the rapid induction of benzo(a)pyrene hydroxylase (BPH). Studies were conducted to determine if dietary fiber would reduce exposure of the intestine to dietary benzo(a)pyrene (BP) as indicated by intestinal BPH activity. In all studies, female Sprague-Dawley rats were fed a fiber-free purified diet for 7 d, whereupon they were switched to experimental diets for 48 h. After 48 h their small intestinal mucosa was assayed for BPH activity. Diets for the initial study contained 0, 100, 400, 800, or 1200 mg BP/kg diet, each with and without 10% soft white wheat bran. Enzyme induction with 100 and 400 mg BP/kg diet was partially inhibited by bran, but with higher concentrations of BP there was no protective effect. The inhibition in BP-induced intestinal BPH activity was observed with 10% wheat bran but not with 3.3 or 6.6%. Subsequent studies showed no significant inhibition in BPH induction with cellulose or lignin, whereas all forms of wheat bran (hard red, soft white, or finely ground soft white) caused significant inhibition. In the final study, a diet containing charcoal-broiled beef, a known source of PAH, was compared with diets containing raw beef or soybean protein, each with and without 10% soft white wheat bran. BPH activity remained low with raw beef and soybean protein whether or not fiber was added. However, intestinal BPH activity was raised ninefold by charcoal-broiled beef. The addition of bran reduced BPH activity to 65% of that observed with the fiber-free, charcoal-broiled beef diet.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interaction of benzo(a)pyrene and cadmium on GSH-S-transferase and benzo(a)pyrene hydroxylase in the black sea bassCentropristis striata

The effect of benzo(a)pyrene (BaP) and cadmium (Cd) upon the hepatic enzymes, BaP hydroxylase and GSH-S-transferase, was investigated in black sea bass. Intraperitoneal (ip) injections of BaP produced a significant increase in BaP hydroxylase activity in the microsomal fraction and GSH-S-transferase activity in the cytosol. Administration of Cd alone had no effect on either enzyme. However, when both Cd and BaP were injected (ip) in the fish, Cd had an inhibitory effect on the activity of these hepatic enzymes. Pretreatment of fish with a low dose of Cd (0.42 mg/kg) prior to injection of BaP and Cd produced a 30% increase in GSH-S-transferase activity and a 50% reduction in BaP hydroxylase activity when compared to fish injected with BaP alone following Cd pretreatment. Thus, a low dose of Cd was effective in producing a tolerance to a subsequent Cd challenge for the enzyme GSH-S-transferase but not for BaP hydroxylase. In contrast, fish pretreated with a high dose of Cd (2.5 mg/kg) prior to BaP treatment alone or with Cd displayed no difference in either enzyme activity. The implications from this study on the exposure of black sea bass to two xenobiotics, Cd and BaP, indicate that BaP hydroxylase may not serve as a good monitor for hydrocarbon pollution in the presence of Cd.     

Kinetics and biotransformation of benzo(a)pyrene inChironomus riparius

Uptake and depuration kinetics for benzo(a)pyrene (B(a)P) were determined for the midgeChironomus riparius (Diptera) with one and two compartment models. Nonfeeding animals were exposed to nominal 1.0μg·L^{?1 14}CB(a)P for eight hr. Depuration over eight hr was determined in animals with and without substrate. The uptake rate constant was 214+-20 hr^?1 (X+-SE, n=3), while elimination rate constants for the first four hr were 0.22 hr^?1 (with substrate) and 0.06 hr^?1 (without substrate). Biphasic depuration was observed with an initial rapid phase that lasted several hr. Approximately 10% of accumulated¹⁴C was associated with exoskeleton. As much as 50% of the accumulated B(a)P was transformed into polar compounds after one hr. Based on steady state¹⁴C concentration, an apparent bioconcentration factor of 650 was determined. The bioconcentration value based on B(a)P analysis was 200.     

苯并(a)芘代谢物反式二羟环氧苯并芘诱发人支气管上皮细胞恶性转化

以不同浓度的苯并 (a)芘代谢物反式二羟环氧苯并芘 (BPDE)多次处理人支气管上皮细胞 16HBE ,并观察转化细胞的恶性特征。发现BPDE可诱导 16HBE细胞恶性转化 ,形成转化灶。转化灶细胞失去接触抑制 ,排列紊乱 ,无方向性 ,交叉重叠生长。转化的细胞可在软琼脂上生长 ,各浓度处理组细胞集落形成率均显著高于对照组 ,有良好的剂量—反应关系。经BPDE处理的细胞在裸鼠体内成瘤 ,病理学诊断为鳞状细胞癌。本实验以反式BPDE成功地诱发了人支气管上皮细胞恶性转化 ,为后期进一步研究其致癌的分子机制、寻找致癌相关基因提供了理想的生物学材料。     

The development of abdominal aortic aneurysms in mice is enhanced by benzo(a)pyrene

Cigarette smoking has been strongly associated with abdominal aortic aneurysm (AAA), but the components of tobacco smoke involved in AAA have not been identified. Benzo(a)pyrene (BaP) is an important constituent in cigarette smoke capable of induction of alterations strikingly similar to the pathological changes seen during AAA development. We therefore hypothesized that BaP exposure contributes to the development of AAA. In this study, C57/B6J mice were treated with vehicle, angiotensin II (AngII) (0.72 mg/kg/day), BaP (10 mg/kg/week), or the combination of AngII and BaP, for 5 weeks, and then examined for incidence of AAA and pathological changes of the aortic wall. Results showed that incidence of AAA formation in C57/B6J mice treated with BaP and AngII was significantly higher than that in AngII-treated mice (7 of 12 compared to 2 of 12). Further, five mice in the group treated with AngII/BaP and one in the group treated with AngII exhibited AAA rupture and hematoma. BaP caused macrophage infiltration, disarray of elastic lamella, and loss of vascular smooth muscle cells (VSMCs). We conclude that BaP aggravates AAA formation and rupture in C57/B6J mice by promoting macrophage infiltration, degeneration of elastic lamella, and loss of VSMCs in the aortic wall.     

苯并[a]芘作用下ADP-核糖基化修饰蛋白分析方法的建立

目的建立苯并[a]芘(B[a]P)作用下ADP-核糖基化修饰蛋白分析方法。方法使用免疫共沉淀技术收集可能发生ADP-核糖基化修饰的蛋白,同步使用高效液相色谱技术和双向电泳技术对蛋白进行分离,再进行MALDI-TOF-MS/MS鉴定,比较两种分离方法鉴定蛋白的差异,并将鉴定蛋白的氨基酸序列与文献报道的ADP-核糖基化修饰蛋白的保守序列进行比对。结果通过高效液相色谱分离结合质谱鉴定找出3个蛋白,双向电泳分离结合质谱鉴定找出12个蛋白,双向电泳分离结合质谱鉴定方法存在明显优势;所鉴定蛋白存在与文献报道的ADP-核糖基化修饰蛋白相似的保守序列。结论免疫共沉淀蛋白双向电泳分离结合质谱鉴定方法可用于分析ADP-核糖基化修饰蛋白,并发现ADP-核糖基化蛋白存在相对保守的结合序列。     

基准剂量在镉接触人群骨效应研究中的应用

目的通过镉接触人群流行病学研究，估测环境镉接触引起人群骨质疏松的基准剂量。方法镉污染区居住的居民为接触组，非污染区居民为对照组。尿镉（UCd）、血镉（BCd）为接触生物标记物；代表骨质疏松的Z评分为效应生物标记物。结果污染区人群尿镉、血镉水平均明显高于对照地区（P〈0．05），且高污染医人群尿镉、血镉水平明显高于中污染区（P〈0．05）。与5μg/gCr组相比，各人群尿镉水平、血镉水平最高组的骨密度均明显降低，差异有统计学意义（P〈0．05）。人群随着体内镉接触水平的升高，骨质疏松的患病率均随之明显升高，有统计学意义（P〈0．05）并有线性关系（P〈0．05）。计算得到基准剂量（BMD），推出基准剂量的95％低限水平（BMDL）。镉所引起的骨质疏松指标的尿镉BMDL值高于镉致肾功能不全指标的BMDL值。结论高剂量镉能引起人群骨质疏松，但时间上晚于镉致肾功能不全的损害。基准剂量是一种值得应用的新方法。     

Effects on rat lung immunity by acute lung exposure to benzo(a)pyrene

This study describes the effect of intratracheal instillation of benzo(a)pyrene (BaP) on immunological responses in the lung-associated lymph nodes, cervical lymph nodes, and spleen after deposition of 10(8) sheep red blood cells (SRBC) in the lung or peritoneal cavity of rats. An increased number of anti-SRBC antibody-forming cells was observed in the lung-associated lymph nodes when rats were immunized simultaneously with BaP installation. A suppression in the number of anti-SRBC antibody-forming cells occurred when SRBC were given intratracheally 4 or 7 days after BaP. The effects of the BaP appeared to be on the function of the cells in the lung-associated lymph nodes rather than due to changes in the exposed lung. BaP-induced changes in antigen handling or in regulatory populations of immune cells in the lung-associated lymph nodes may be responsible for the immune alterations observed.     

苯并（a）芘对淋巴细胞钙稳态的影响及其与免疫抑制的关系

利用一次腹腔注射的染毒方法观察了苯并（ａ）在（ＢａＰ）对小鼠脾淋巴细胞钙稳态的影响，并初步探讨了其与免疫抑制的关系。结果表明，ＬＡＣＡ雌性小鼠一次腹腔注射ＢａＰ２００ｍｇ／ｋｇ后第３天和第６天，胸腺和脾脏明显萎缩，与对照组比其相对重量分别下降４６．０％～４９．２％和２８．７％～３３．０％；全脾细胞数明显减少，同时刀豆素Ａ（ＣｏｎＡ）刺激的淋巴细胞增殖反应也受到明显抑制，抑制率为２１．１％～２７．５％；淋巴细胞内游离钙浓度（［Ｃａ￣(２＋)］ｉ）在染毒后第３天明显升高，第６天明显下降；不同剂量ＢａＰ染毒后第３天淋巴细胞内［Ｃａ￣(２＋)］ｉ与染毒剂量呈明显正相关（ｒ＝０．９８５３，Ｐ＜０．０１）；第６天［Ｃａ￣(２＋)］ｉ与染毒剂量呈明显负相关（ｒ＝－０．９４７３，Ｐ＜０．０１）。此外，还观察到钙离子载体Ａ＿(２３１８７)使正常小鼠脾淋巴细胞［Ｃａ￣(２＋)］ｉ明显升高时，淋巴细胞增殖反应受到明显抑制。结果提示，ＢａＰ可明显影响小鼠脾淋巴细胞的钙稳态，而钙稳态的失衡与ＢａＰ引起的免疫抑制可能有密切的关系。