Persistent organic pollutants in red-crowned cranes (Grus japonensis) from Hokkaido, Japan

The red-crowned crane (Grus japonensis) from eastern Hokkaido is classified as a Special Natural Monument in Japan. In this study, we determined the concentrations of persistent organic pollutants (POPs) in red-crowned crane muscle tissues (n = 47). Polychlorinated biphenyls (PCBs) had the highest median concentration (240ng/g lipid weight), followed by dichlorodiphenyltrichloroethane and its metabolites (DDTs) (150ng/g lipid weight), chlordane-related compounds (CHLs) (36ng/g lipid weight), hexachlorobenzene (HCB) (16ng/g lipid weight), hexachlorocyclohexanes (HCHs) (4.4ng/g lipid weight), polybrominated diphenyl ethers (PBDEs) (1.8ng/g lipid weight), and finally, Mirex (1.5ng/g lipid weight). Additionally, a positive correlation was found among POP concentrations. No sex differences beyond body parameters were observed. Additionally, red-crowned cranes exhibited a high enantiomeric excess of (+)-alpha-HCH, with enantiomer fractions varying from 0.51 to 0.87 (average: 0.69).

Acute effects of diesel emission from the urea selective catalytic reduction engine system on male rats

Short-term inhalation experiments were performed using Fischer 344 rats exposed to emission from the urea selective catalytic reduction (SCR) diesel engine system to identify health effects and compare them to those of the conventional diesel engine system. Rats were exposed to high-, middle-, or low-concentration emission (dilution ratio 1:29, 1:290, or 1:580) or clean air (control) for 1, 3, or 7 days (6 h/day), under driving conditions at a speed of 1320 rpm and a torque of 840 Nm. For the high-concentration group, the major components of the urea SCR emission were 0.04 mg/m(3) particulate matter (PM) and 0.78 ppm nitrogen dioxide (NO(2)); those of the conventional emission were 0.95 mg/m(3) PM and 0.31 ppm NO(2). The authors evaluated the respiratory effects of each emission on rats. Lymphocytes for 3-day exposure of both emissions significantly increased in bronchoalveolar lavage fluid, but there were slight differences. With an increase in potential antioxidant (PAO), 8-hydroxy-2'-deoxyguanosine for the urea SCR emission was significantly decreased, but that of the conventional emission was highest among all groups and did not show a response to PAO. In lungs, heme oxygenase (HO)-1 and tumor necrosis factor (TNF)-alpha mRNA expressions for the urea SCR emission showed a tendency to increase compared to those of the conventional emission. Thus, gene analysis results suggested that NO(2) from the urea SCR emission affected the expressions of mRNAs in lungs. However, as a whole, the results suggested that the health effects of the urea SCR emission might be less than the conventional emission on rats.

Prenatal Exposure to Diesel Exhaust Impairs Mouse Spermatogenesis

The effect of prenatal exposure to diesel exhaust (DE) was investigated. Twenty pregnant ICR mice were exposed to DE at the particle concentration of 1.0 mg/m3, from d 2 until d 16 postcoitum. Male offspring were kept alive until 12 wk of age, and then male reproductive organ weight, daily sperm production (DSP), serum testosterone level, and mRNA expression of sex steroid hormone synthesis process-related factors were measured. Serum testosterone levels of the exposed group were reduced significantly at 3 wk, whereas they were elevated significantly at 12 wk. DSP was also markedly reduced at 5 and 12 wk. Histological examination showed multinucleated giant cells in the seminiferous tubules of the exposed group as well as partial vacuolation of the seminiferous tubules. Follicle-stimulating hormone receptor (FSHR) mRNA expression and steroidogenesis acute regulatory (StAR) protein were significantly increased at 5 wk and 12 wk, respectively. This study suggests that prenatal exposure to DE has detrimental effects on mouse spermatogenesis in offspring.

Effect of diesel exhaust particles on mRNA expression of viral and bacterial receptors in rat lung epithelial L2 cells

Epidemiological studies have shown that particulate matter (PM) is associated with adverse respiratory health effects. Although infection in the respiratory organ is one of the most important health risks the association of infection with PM is not fully understood. As we had hypothesized that diesel exhaust particles (DEP), one of the major component of PM, may induce the expression of receptors for viruses and bacteria at invasion sites, we studied the effect of DEP on the mRNA expression of intercellular adhesion molecule-1 (ICAM-1), low-density lipoprotein (LDL) and platelet-activating factor (PAF) receptors, which are invasion sites of virus and bacteria, on rat lung epithelial cells. The real-time quantitative polymerase chain reaction (PCR) method was used for the evaluation. All of these mRNAs were up-regulated by 3, 10, and 30 microg/ml of DEP in a concentration-dependent manner. The up-regulation of each was associated with the mRNA expression of heme oxygenase-1 (HO-1), a marker of oxidative stress. Our present results show that DEP up-regulated the mRNA expression of viral and bacterial receptors. This up-regulation might be associated with DEP-induced oxidative stress. These results thus suggest that DEP may enhance the risk of pneumonia by increasing the density of bacterial and viral invasion sites in the lungs.

In utero exposure to diesel exhaust increased accessory reproductive gland weight and serum testosterone concentration in male mice

The effects of in utero exposure to diesel exhaust (DE) on the male mouse reproductive system were examined. Pregnant ICR mice inhaled DE at soot concentrations of 0.3, 1.0, or 3.0 mg DEP/m3 or clean air as the control, for 2-16 days postcoitum. On postnatal day (PND) 28, the weights of the testes and accessory glands and testosterone concentration in serum were significantly higher in the DE-exposed male pups. Testosterone concentration correlated significantly (P<0.01) with the expression levels of steroidogenic enzyme mRNAs, weights of the testes and male reproductive accessory glands, and daily sperm production. These findings indicate that very early stage mouse embryo exposure to DE leads to endocrine disruption after birth and acceleration of male puberty.

Diesel exhaust affects immunological action in the placentas of mice

We investigated the effect of diesel exhaust (DE) on pregnancy and fetal development in mice at day 14 postcoitum (pc) with a special focus on the placenta. The number of absorbed fetuses increased in groups exposed to DE, and congestion was observed in histological sections of placentas. During placental absorption expression of CYP1A1 mRNA decreased to undetectable levels, whereas expression of TNF alpha mRNA increased approximately twofold over that of the control. Levels of CYP1A1 mRNA in normal placentas from DE-exposed mice were unchanged. mRNA levels of inflammatory cytokines IL-2, IL-5, IL-12 alpha, IL-12 beta, and GM-CSF increased in placentas exposed to DE (0.3 and 3.0 mg diesel exhaust particles (DEP)/m3). Expression of IL-5 mRNA was markedly increased in DE-exposed placentas, although levels were barely detectable in control placentas. IL-6 mRNA expression was increased approximately 10-fold in placentas exposed to DE (3.0 mg DEP/m3). It has been reported that expression of mRNA encoding proteins involved in immune function in the placenta is increased during fetal absorption in mice. In the present study, expression of such mRNA by the placenta was increased by DE exposure. Because it is believed that expression of mRNA in the placenta also affects fetal development, DE may promote fetal absorption. These findings suggest that in mice exposure to DE affects fetal absorption and placental function by modifying expression of immune-related genes during early gestation and expression of endocrine-related genes during late gestation.

Endocrine-disrupting activity of chemicals in diesel exhaust and diesel exhaust particles

Diesel exhaust (DE) is known as the main cause of air pollution. DE is a complex mixture of particulate and vapor-phase compounds. The soluble organic fraction of the particulate materials in DE contains thousands of compounds including a variety of polycyclic aromatic hydrocarbons and heavy metals. To clarify the endocrine-disrupting activities of DE, we have reviewed the reports about the effects of DE on the reproductive and brain-nervous systems, and the endocrine-disrupting action of diesel exhaust particles (DEP). In utero exposure to low levels (0.1 mg DEP/m3) of DE from day 2 postcoitum (p.c.) until day 13 p.c. reduced the expression level of Ad4BP/SF-1 mRNA and thereby might affect the development of gonads. Low levels of DE also reduced the expression of several genes known to play key roles in gonadal development, including an enzyme necessary for testosterone synthesis. Mature male rats exposed to DE during the fetal period showed an irreversible decrease in daily sperm production due to an insufficient number of Sertoli cells. DE exposure during the fetal period influenced the brain tissue in newborn mice. In the 3 mg DEP/m3 exposure group at 10 weeks of age, a significant reduction in performance was observed in the passive avoidance learning test in both male and female mice. In addition, the fetal exposure of mice to DE affected the emotional behaviors associated with the serotonergic and dopaminergic systems in the mouse brain. In toluidine blue-stained specimens from the DE-exposed group, edema around the vessels where fluorescent granular perithelial (FGP) cells exist and degenerated granules within the FGP cytoplasm were observed; similar findings were obtained by electron microscopic examination. DEP contain many substances that stimulate Ah receptors, such as the polycyclic aromatic hydrocarbon containing benzo[a]pyrene. DEP also contain substances with estrogenic, antiestrogenic and antiandrogenic activities. The neutral substance fraction of DEP has the causal substance that reduces estrogen receptor mRNA expression. Evaluating the influence of these chemicals present in the environment on human health is an important task.

Diesel exhaust affects the abnormal delivery in pregnant mice and the growth of their young

To clarify the toxic effects of diesel exhaust (DE) on delivery in mice and on growth of young, C57Bl-strain females were exposed to 0.3, 1.0, or 3.0 mg diesel exhaust particles (DEP)/m3 or filtered clean air (control) for 4 mo (12 h/day, 7 days/wk). After exposure, some females from each group were examined by necropsy, and the remainders were mated with unexposed males. Estrous females for necropsy who had been exposed to 1.0 mg DEP/m3 had significantly lower uterine weights than the control estrous females. In the mated females, 9.1, 10.0, or 25.0% (0.3, 1.0, or 3.0 mg DEP/m3 of the pregnancies resulted in abnormal deliveries (abortion and unable delivery), but this was not significant. The rate of good nest construction by delivered females exposed to 3.0 mg DEP/m3 was significantly lower. Young were weighed at 11, 14, and 21 days, and weekly from wk 4 to 9 after birth. Body weights of male young of dams exposed to 1.0 or 3.0 mg DEP/m3 were significantly lower at 6 and 8 wk of age. Body weights of female young of dams exposed to 1.0 or 3.0 mg DEP/m3 were also significantly lower at 6, 8, and 9 wk. Vaginal orifices of young female mice whose dams were exposed to 0.3 and 1.0 mg DEP/m3 opened significantly earlier. The young were killed at 30 or 70 days during deep anesthesia, and their body weights, organ weights, and body lengths were measured. Anogenital distance (AGD) of 30-day-old males whose dams were exposed to 0.3 mg DEP/m3 was significantly shorter than that of the controls. Weights of thymus and ovary in 30-day-old females whose dams were exposed to 3.0 mg DEP/m3 were significantly lower. In 70-day-old males of dams exposed to 3.0 mg DEP/m3, body weights were significantly lower and AGD was significantly shorter. Weights of adrenals, testes, and seminal vesicles in 70-day-old males with dams exposed to 1.0 mg DEP/m3 were significantly lower. In 70-day-old females with dams exposed to DE, body weights in the 3.0-mg DEP/m3 group were significantly lower, and weights of adrenals, liver, and thymus in the 1.0-mg DEP/m3 group were significantly lower. Thymus weights in 70-day-old females with dams exposed to 0.3 mg DEP/m3 were significantly lower. Crown-rump length (CR) in 70-day-old females with dams exposed to 1.0 or 3.0 mg DEP/m3 was significantly shorter. These results show that toxic substances in DE might cause abnormal delivery in mice, and that exposed females affected the growth and sexual maturation of their young.

Effects of diesel exhaust particles on blood pressure in rats

The effects of diesel exhaust particles (DEP) on pulmonary functions and consequent diseases are well known, but there have been few reports concerning involvement of the cardiovascular system. In order to assess a direct action of DEP on cardiac tissue, the effects on blood pressure of intravenous administration of 12 or 120 mg/kg DEP to anesthetized rats were studied for a 15-min period. DEP (120 mg/kg) significantly lowered blood pressure for 25 s with no signs of arrhythmia or mortality, a phenomenon seen in guinea pigs. After 25 s blood pressure gradually returned to control levels and was maintained for 15 min. The 12-mg/kg DEP concentration did not markedly affect rat blood pressure. Pretreatment with atropine (24 mg/kg) blocked the DEP-induced fall in blood pressure, while pretreatment with propranolol (48 mg/kg) proved ineffective against DEP, suggesting involvement of the parasympathetic system. Data show that the rat is less sensitive to DEP-induced effects on blood pressure and may be a poor model to reflect cardiovascular changes.

Diesel exhaust (DE) affects the regulation of testicular function in male Fischer 344 rats

To investigate the effects of diesel exhaust (DE) particles on the reproductive system, male Fischer 344 rats at 13 mo of age were exposed to clean air or DE at particle concentrations of 0.3, 1, or 3 mg/m3 for 8 mo. DE did not markedly affect testicular and body weights. However, DE at 0.3 mg/m3 significantly decreased prostate and coagulating gland weights, accompanied by a reduction in thymus and adrenal gland weight. In contrast, there was a significant rise in the weights of prostate, seminal vesicles, and coagulating glands in the 3 mg/m3 DE group. In rats exposed to 0.3 or 1 mg/m3 DE, serum luteinizing hormone (LH) and testosterone increased significantly, while a rise in testicular testosterone was noted with 3 mg/m3 DE. The concentrations of follicle-stimulating hormone (FSH) and inhibin as well as the sperm head counts were not markedly altered in any treatment group. Positive staining with inhibin-alpha subunit and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) were observed in Sertoli cells and Leydig cells, respectively. Immunolocalization of inhibin-alpha subunit and 3beta-HSD was not changed by exposure to DE. In conclusion, DE appears to exert greater effects on accessory glands than on testes in Fischer 344 rats, and the responsiveness of rats is less than that found in mice.