Journal of Toxicology and Environmental Health-Part A-Current Issues最新文献

Fish early life stages are well known for their sensitivity to crude oil exposure. However, the effect of crude oil exposure on adults and their gametes during their spawning period is not well studied. Polar cod, a key arctic fish, may be at risk for crude oil exposure during this potentially sensitive life stage. Additionally, this species experiences lower food availability during their spawning season, with unknown combined consequences. In the present study, wild-caught polar cod were exposed to decreasing levels of a water-soluble fraction (WSF) of crude oil or control conditions and fed either at a low or high feed ration to assess the combined effect of both stressors. Samples were taken during late gonadal development, during active spawning (spawning window), and in the post-spawning period. Histology analysis of gonads from fish sampled during the spawning window showed that oil-exposed polar cod were more likely to have spawned compared to controls. Oil-exposed females had 947 differentially regulated hepatic genes, and their eggs had a higher polycyclic aromatic hydrocarbon body burden compared to controls. Feed ration did not consistently affect polar cod's response to oil exposure for the endpoints measured, however, did alone result in decreases in some sperm motility parameters. These results suggest that polar cod's spawning period is a sensitive life event to crude oil exposure, while feed limitation may play a minor role for this supposedly capital breeder. The effects of adult exposure to crude oil on gamete quality and the next generation warrant further investigation.

The global phenomenon of cyanobacterial bloom pollution is spreading globally due to climate change and eutrophication. It is well established that harmful cyanobacteria produce a wide range of toxins including microcystin-LR (MC-LR), a cyclic heptapeptide toxin known to damage various organs. The intestinal tract is the main site of MC-LR absorption and one of the targets susceptible to toxicity. Currently, studies on the enterotoxic effects of MC-LR predominantly focused on the colorectum, with limited investigations addressing the impact of microcystins on the small intestine. Therefore, the aim of our study was to examine the impact of chronic 9-month exposure of mice to low-dose 120 μg/L MC-LR in drinking water on ileal inflammation and potential mechanisms underlying these effects. Our findings showed that in mice chronically administered with low-dose MC-LR disorganized intestinal epithelial cells, lymphocytic infiltration and disturbed crypt arrangement were detected. The results of qPCR and Western blot demonstrated that, in comparison to control, the mRNA expression levels of pro-inflammatory factors IL-6, IL-17, IL-18, and IFN-γ were markedly elevated in the ileal tissue of mice treated with MC-LR, associated with significant increases in protein expression levels of p-PI3K, p-AKT, and p-mTOR. Taken together, evidence indicates that MC-LR induces ileal inflammation and histopathological damage involved activation of the PI3K/AKT/mTOR signaling pathway.

Higher coil temperature in e-cigarette devices increases the formation of aerosols and toxicants, such as carbonyls. At present, the health implications of vaping at higher temperatures, including exacerbation of pulmonary inflammation, are largely unknown when aerosol dose is considered. To isolate the pulmonary effects of coil temperature, C57BL/6 mice were exposed to e-cigarette aerosols generated at lower (190°C) or higher (250°C) temperature for 3 days, while maintaining a similar chamber aerosol concentration. Increasing coil temperature did not markedly alter aerosol mass-normalized emissions of select carbonyls formed from thermal degradation pathways including formaldehyde, acetaldehyde, propionaldehyde, and acetone under the tested environment. Total bronchoalveolar cells, primarily macrophages, were significantly decreased in mice exposed to aerosols generated with higher coil temperatures compared to lower temperature exposures. The gene expression of IFNβ, IL-1β, TNFα, and IL-10 in mouse lung tissue was significantly reduced following e-cigarette exposure under both conditions, compared to filtered air exposure. Higher temperature exposures further exacerbated downregulation of IFNβ and IL-1β. Data suggest that higher temperature vaping might modulate acute pulmonary immune responses, potentially inducing immune suppression, even when normalized for aerosol dose exposure. Coil temperature thus appears to be an important parameter that needs to be regulated to ensure harm reduction for e-cigarette users.

The International Agency for Research on Cancer (IARC) classifies exposure to fine particulate matter (PM_2.5) air pollution as carcinogenic to humans (Group I), most frequently associated with lung cancer. Airborne air pollutants may be associated with other sites of cancer, although few studies have examined this avenue of research. Esophageal cancer mortality rates vary substantially across townships in Taiwan, a fact that suggests environment influence. Therefore, the aim of this study was to investigate the association between long-term exposure to ambient PM_2.5 and deaths attributed to esophageal cancer in 66 municipal areas across Taiwan. To conduct this study, annual PM_2.5 levels were determined taking into account age-standardized esophageal cancer mortality rates in male and female residents of these municipalities from 2012 to 2021. The annual PM_2.5 levels of each municipality were divided into tertiles and computed adjusted risk ratio (RR) using weighted-multiple regression analyses controlling for municipal lung cancer deaths, urbanization level, and physician density. Men residing in those areas with intermediate PM_2.5 tertile levels (18.96-25.19 ug/m³) were found to have an adjusted RR of 1.22 (1.15-1.30) and those of residing areas with the highest tertiles levels (25.20-29.48 ug/m³) exhibited an RR of 1.11 (1.051.18). However, in women in the same municipalities, a significant inverse association was found between PM_2.5 levels and mortality attributed to esophageal cancer, 0.82 (95% CI = 0.65-1.04) and 0.61 (95% CI = 0.47-0.79), respectively. These findings suggest that long-term exposure to PM_2.5 increases the risk of developing esophageal cancer in men in Taiwan.

There is a need to assess whether ecological resources are being protected on large, federal lands. The aim of this study was to present a methodology which consistently and transparently determines whether two large Department of Energy (U.S. DOE) facilities have protected valuable ecological lands on their sites compared to the surrounding region. The National Land Cover Database (2019) was used to examine the % shrub-scrub (shrub-steppe) and other habitats on the DOE's Hanford Site (HS, Washington) and on the Idaho National Laboratory (INL), compared to a 10-km and 30-km diameter band of land surrounding each site. On both sites, over 95% is in shrub-scrub or grassland, compared to the surrounding region. Approximately 70% of 10 km and 30-km bands around INL, and less than 50% of land surrounding HS is located in these two habitat types. INL has preserved a significantly higher % shrub/scrub habitat than HS, but INL allows grazing on 60% of its land. HS has preserved a significantly higher % grassland than INL but no grazing on site is present. The methodology presented may be used to compare key ecological habitat types such as grasslands, forest, and desert among sites in different parts of the country. This methodology enables managers, resource trustees, and the public to (1) make remediation decisions that protect resources, (2) assess whether landowners and managers have adequately characterized and protected environmental resources on their sites, and (3) whether landowners and managers have protected the integrity of that land as well as its climax vegetation.

The covalent binding of sensitizer to skin proteins is referred to as key event 1 of the adverse outcome pathway in skin sensitization. Recently, N-acetyl-L-cysteine methyl ester (NACME) was demonstrated to react selectively with skin sensitizers in vitro, such that NACME might be applied as an electron donor in developing a spectrophotometric test for determining skin sensitization potential of chemicals. To avoid possible color interference by certain test chemicals, a fluorometric test method was developed using monobromobimane (mBBr), a thiol-reactive fluorescent probe. Similar to previous methods utilizing the reaction of NACME with sensitizers, unreacted NACME occurred which was then measured fluorometrically using mBBr, rather than 5,5'-dithio-bis-(2-nitrobenzoic acid) (DTNB). Following the optimization of test conditions, the same 64 test chemicals used in the previous study were tested to determine the predictive capacity of the current method. Results showed a predictive capacity of 81.1% sensitivity, 81.5% specificity, and 81.3% accuracy with a cutoff NACME depletion of 11.3%. Although these values were relatively lower than the previous test using DTNB, the results were still comparable to OECD-approved test methods and that color interference issues might be ruled out. Data demonstrated that NACME might be viewed as a candidate for identifying reactive skin sensitizers. Further, this method might be considered as a complementary or supportive method to the former DTNB assay as a screening tool for assessing the tendency of a chemical to initiate skin sensitization in case of test chemicals showing color interference.

Hymenaea courbaril L. (H. courbaril) is a South American native species frequently used to treat various symptoms and illnesses, including anemia, fatigue, inflammation, pain, respiratory conditions, kidney and prostate disorders, cancer, diabetes, arthritis, rheumatism, gastric and hepatic dysfunctions, and skin conditions. This study aimed to examine the in vivo toxicity attributed to H. courbaril stem bark hydroalcoholic extract and its effects on physiological conditions and stress responses. Different strains of Caenorhabditis elegans (C. elegans) were employed. The LC₅₀ of H. courbaril extract in N2 wild-type (L4) worms was 15,076.99 ± 1,66 µg/ml. The extract reduced survival to 92.96% at the highest concentration tested (1600 μg/ml; 24 hr), and after 72 hr treatment, concentrations of 800 or 1600 μg/ml decreased survival to 84.7% and 82.8%, respectively. Body development of C. elegans was also affected by higher concentrations, where only 1600 μg/ml diminished reproduction by 87.88%. Exposure to heat stress reduced C. elegans survival in a time-dependent manner. Also, protected worms against oxidative damage induced by hydrogen peroxide (H₂O₂,) at different concentrations and times and decreased expression of superoxide dismutase-3(SOD-3)(800 μg/ml; 1600 μg/ml), glutathione-S-transferase-4 (GST-4) (800 μg/ml), and catalase (CTL)-1/2/3) (400; 800 μg/ml), suggesting that protection may involve modulation of the decay-accelerating factor-2 (DAF-2) and SKN-1 transcription factor pathways. In conclusion, H. courbaril extract exhibited a low toxicity profile at the concentrations tested and under the conditions used in the study. The extract may serve as a potential antioxidant and stress-protective agent associated with modulation DAF-2 and SKN-1 pathway.

Ioxynil octanoate, considered to be non-genotoxic, is widely used as a post-emergence herbicide. However, extensive agricultural usage might potentially adversely affect non-target organisms, indicating the need for a comprehensive toxicological reassessment. The aim of this study was to investigate the phytotoxic and cytogenotoxic effects attributed to exposure to this herbicide on Allium cepa L. examining germination, early growth, cell cycle progression, and genomic stability. Herbicide concentrations of 52, 209, 837, or 3350 ppm were tested. Distilled water was used as a negative control, while 10 ppm methyl methanesulfonate (MMS) served as a positive control in the comet assay. Parameters determined included germination, root and shoot growth, biomass accumulation, qualitative lipid peroxidation, mitotic index, chromosomal aberrations, and DNA fragmentation via the comet assay. All tested concentrations significantly reduced seed germination and seedling development, with 3350 ppm completely inhibiting normal growth. Histochemical analysis demonstrated significant oxidative stress. A mitodepressive effect exceeding 72% was observed after 72 hr exposure. DNA fragmentation induced by 837 and 3350 ppm was comparable to that of MMS. The association between comet assay results and the presence of micronuclei reinforces the compromise of genomic stability in A. cepa exposed to the compound. Data demonstrated that ioxynil octanoate, even at field-relevant concentrations, impaired cell division, and genomic integrity, indicative of significant cytogenotoxicity. These findings emphasize the need to reevaluate agricultural use of ioxynil octanoate, considering potential environmental risks to non-target organisms and the importance of complementary genotoxicological studies involving both target and non-target organisms.

Herbicides have been extensively researched due to widespread use in agriculture, consequently raising concerns regarding their environmental impact and potential adverse effects on non-target organisms, including humans. Nicosulfuron is a post-emergence herbicide used to control annual or perennial grasses and broad-leaved weeds. In contrast, S-metolachlor is primarily employed as a pre-emergence herbicide for managing annual grasses and certain broad-leaved weeds in intensive cropping systems. This study aimed to assess the effects of two commercial herbicides, one based upon nicosulfuron and the other upon S-metolachlor active ingredients, on the early developmental stages of the plant models Lactuca sativa L. (lettuce), Raphanus sativus (radish), Pennisetum glaucum (L.) R. Br. (millet), and Triticum aestivum (wheat), as evidenced from germination and seedling development bioassays. Results indicated that all plant models exhibited phytotoxic responses, including inhibited germination, reduced germination speed index, and impaired seedling growth and development, ultimately leading to decreased fresh weight. Among the plant species tested, T. aestivum was the most sensitive, while R. sativus was the least affected. Data suggest that nicosulfuron and S-metolachlor-based herbicides exert significant phytotoxic effects on non-target plants, offering valuable insights for future research on the environmental impacts of these substances.

Myocardial ischemia reperfusion injury (MIRI) remains a major clinical challenge. Polyphenols derived from Potentilla anserina L (PPA) were found to possess anti-hypoxic-ischemic in vitro. The aim of this study was to examine (1) whether this plant exerts a protective effect and (2) whether the underlying mechanisms involving inflammatory responses and the Wnt/β-catenin signaling pathway were involved in rats. Rats were randomly divided as follows (1): Sham operation (2); ischemia-reperfusion (MIRI) (3); polyphenols (PPA) (4); Wnt inhibitor group (XAV939). In cardiomyocytes (1), HE staining was used to examine morphology (2), enzyme-linked immunosorbent assay to determine interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) levels and (3) Western blot to measure protein expression of Wnt and β-catenin. HE staining showed in MIRI edema of cardiomyocytes, localized inflammatory cell infiltration, unclear outline of cells and cell fragmentation, and some cardiomyocytes were seen to have disordered arrangement of tissues. PPA markedly lowered the morphological alterations in MIRI. The levels of levels of IL-1β and TNF-α in MIRI were significantly elevated; however, PPA reduced these cytokine concentrations compared to MIRI. Western blot analysis demonstrated that MIRI increased the relative protein expression levels of Wnt and β-catenin. Treatment of MIRI with PPA resulted in a significant decrease in protein expression levels of Wnt and β-catenin. The involvement of the Wnt/β-catenin pathway in MIRI was further affirmed with the use Wnt inhibitor group (XAV939) that also diminished protein expression levels of Wnt and β-catenin.