Toxicology and Industrial Health最新文献

Good mechanical properties and low costs have led to a global expansion of plastic production and use. Unfortunately, much of this material can be released into the environment as a waste product and cleaved into micro- and nanoplastics (NPs) whose impact on the environment and human health is still largely unknown. Considering the growing worldwide awareness on exposure to chemicals that can act as endocrine disruptors, a systematic review was performed to assess the impact of NPs on the endocrine function of in vitro and in vivo models. Although a limited number of investigations is currently available, retrieved findings showed that NPs may induce changes in endocrine system functionality, with evident alterations in reproductive and thyroid hormones and gene expression patterns, also with a trans-generational impact. Nanoplastic size, concentration, and the co-exposure to other endocrine disrupting pollutants may have an influencing role on these effects. Overall, although it is still too early to draw conclusions regarding the human health risks derived from NPs, these preliminary results support the need for further studies employing a wider range of plastic polymer types, concentrations, and time points as well as species and life stages to address a great variety of endocrine outcomes and to achieve a broader and shared consensus on the role of NPs as endocrine disruptors.

Manganese (Mn) is an abundant element used for commercial purposes and is essential for the proper function of biological systems. Chronic exposure to high Mn concentrations causes Manganism, a Parkinson's-like neurological disorder. The pathophysiological mechanism of Manganism remains unknown; however, it involves mitochondrial dysfunction and oxidative stress. This study assessed the neuroprotective effect of probucol, a hypolipidemic agent with anti-inflammatory and antioxidant properties, on cell viability and oxidative stress in slices of the cerebral cortex and striatum from adult male Wistar rats. Brain structure slices were kept separately and incubated with manganese chloride (MnCl₂) and probucol to evaluate the cell viability and oxidative parameters. Probucol prevented Mn toxicity in the cerebral cortex and striatum, as evidenced by the preservation of cell viability observed with probucol (10 and 30 μM) pre-treatment, as well as the prevention of mitochondrial complex I inhibition in the striatum (30 μM). These findings support the protective antioxidant action of probucol, attributed to its ability to prevent cell death and mitigate Mn-induced mitochondrial dysfunction.

Textile effluents, although their composition can vary considerably, typically contain high levels of dissolved salts and exhibit wide variations in pH. Ecotoxicological studies regarding the effects of these parameters, however, have been limited owing to the need for sensitive and easy-to-handle bioindicators that require low amounts of sampling, are cost-effective, time-efficient, and ethically endorsed. This kind of study, additionally, demands robust multi-factorial statistical designs that can accurately characterize the individual and combined relationship between variables. In this research, Response Surface Methodology (RSM) was used to calculate the individual and interaction effects of NaCl concentration and pH value of a Simulated Textile Effluent (STE) on the development rate (DR) of the bioindicators: Bacillus subtilis bacteria and Lactuca sativa lettuce. The results demonstrated that the bioindicators were sensitive to both NaCl and pH factors, where the relative sensitivity relationship was B. subtilis > L. sativa. The quadratic equations generated in the experiments indicated that increased concentrations of 50-250 mg L^-1 of NaCl caused a perturbance of 1.40%-34.40% on the DR of B. subtilis and 0.50%-12.30% on L. sativa. The pH factor at values of 3-11 caused an alteration of 27.00%-64.78% on the DR of the B. subtilis and 51.37%-37.37% on the L. sativa. These findings suggest that the selected bioindicators could serve as effective tools to assess the ecotoxicological effects of textile effluents on different ecological systems, and the RSM was an excellent tool to consider the ecotoxicological effects of the parameters and to describe the behavior of the results. In conclusion, the NaCl and pH factors may be responsible for disrupting different ecosystems, causing imbalances in their biodiversity and biomass. Before discharge or reuse, it is suggested to remove salts and neutralize pH from textile effluents and, mostly, develop novel, eco-friendlier textile processing techniques.

Methomyl is a carbamate insecticide with confirmed testicular toxicity. This study intended to observe the effect of methomyl on testicular cells and the protective effect of folic acid through in vitro experiments. The GC-1 spermatogonia, TM4 Sertoli cells, and TM3 Leydig cells were treated with methomyl (0, 250, 500, and 1000 μM) with or without folic acid (0, 10, 100, and 1000 nM) for 24 h. It was found that methomyl increased cytotoxicity to testicular cells in a dose-dependent manner. In spermatogonia, methomyl significantly inhibited the expression of proliferation genes Ki67 and PCNA at 1000 μM, and increased the expression of apoptosis genes Caspase3 and Bax at each dose. In Sertoli cells, methomyl dose-dependently inhibited the expression of blood-testis barrier function genes TJP1, Cx43, and N-cadherin, but did not affect Occludin and E-cadherin. In Leydig cells, methomyl inhibited the expression of steroid synthase P450scc, StAR, Hsd3b1 and down-regulated the level of testosterone, but did not affect Cyp17a1 and Hsd17b1. Further, folic acid could basically reduce the damage caused by methomyl. This study provided new insights into the toxicity of methomyl and the protective effect of folic acid.

Phthalate compounds were found to disrupt the endocrine system and alter transcriptomes during human embryonic development. In our previous work, we have isolated and reported two such phthalates di-(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) from Brevibacterium mcbrellneri bacteria and evaluated their bioactive properties. Naturally derived phthalates might be less toxic compared with synthesized molecules. We have investigated biologically isolated phthalates to understand the possible genotoxic effects in mice and further investigated in silico binding and polymerization of β-tubulin. Three sub-lethal concentrations of DEHP (150 μM, 175 μM, and 200 μM) and DBP (10 μM, 15 μM, and 30 μM) were studied. The results showed that the phthalates were found to be highly genotoxic in nature. However, the pattern of genotoxic effects was not found to be dose-dependent in the induction of chromosome aberrations (CA), micronuclei (MN), and changes in the mitotic index (MI) in cells. In silico studies of phthalates on polymerization of β-tubulin suggested that both DBP and DEHP were able to interact with the hydrogen bonds and make strong van der Waals interactions with β-tubulin thereby possibly causing destabilization of microtubule network. Our study suggests that these phthalates might be playing an important role in normal cell division thereby showing highly genotoxic effects.

Trichloroethylene (TCE) is a metal detergent commonly used in industry that can enter the human body through the respiratory tract and skin, causing occupational medicamentosa-like dermatitis due to TCE (OMDT) and multiple organ damage, including liver failure. However, the pathogenesis of liver injury remains unclear. Kupffer cells (KCs) are important tissue macrophages in the body because the polarization of KCs plays a crucial role in immune-mediated liver injury. However, the mechanism of KCs polarization in TCE-induced immune liver injury has not been thoroughly elucidated. In this study, we investigated the effect of TCE-induced KCs polarization on liver function and signal transduction pathways using the TCE sensitization model developed by our group. BALB/c mouse skin was exposed to TCE for sensitization, and an increase in the expression of M1 macrophage-specific markers (CD16/CD32, iNOS), M1 macrophage-specific cytokines IL-1β, and IFN-γ, P-JAK-1 and P-STAT1 levels were also found to be dramatically increased. When using low doses of gadolinium trichloride (GdCl₃), the expression of these proteins and mRNA was significantly reduced. This phenomenon indicates that GdCl₃ blocks TCE-induced polarization of KCs and suggests that the IFN-γ/STAT1 signaling pathway may be involved in the polarization process of KCs. These findings clarify the relationship between the polarization of KCs and immune liver injury and highlight the importance of further study of immune-mediated liver injury in TCE-sensitized mice.

Man-made vitreous fibers (MMVF) are a class of inorganic fibrous materials that include glass and mineral wools, continuous glass filaments, and refractory ceramic fibers valued for their insulative properties in high temperature applications. Potential health effects from occupational exposure to MMVF have been investigated since the 1970s, with focus on incidence of respiratory tract cancer among MMVF-exposed production workers. The general population may experience exposure to MMVF in residential and/or commercial buildings due to deterioration, construction, or other disruption of materials containing these fibers. Numerous studies have characterized potential exposures that may occur during material disruption or installation; however, fewer have aimed to measure background MMVF concentrations in residential and commercial spaces (i.e., non-production settings) to which the general population may be exposed. In this study, we reviewed and synthesized peer-reviewed studies that evaluated respirable MMVF exposure levels in non-production, indoor environments. Among studies that analyzed airborne respirable MMVF concentrations, 110-fold and 1.5-fold differences in estimated concentrations were observed for those studies utilizing phase contrast optical microscopy (PCOM) versus transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. A positive correlation was observed between respirable air concentrations of MMVF and total surface concentrations of MMVF in seldom-cleaned areas. Ultimately, available evidence suggests that both ambient air and surface concentrations of MMVF in indoor environments are consistently lower than exposure limits developed to prevent negative health outcomes among sensitive populations.

To meet the strict requirements of reducing sulfur emissions, an increasing number of commercial ships have installed exhaust gas cleaning systems (EGCSs). However, wash water produced during the cleaning process is discharged back to the marine environment. We investigated the effects of closed-loop scrubber (natrium-alkali method) wash water on three trophic species. Severe toxic effects were found when Dunaliella salina, Mysidopsis bahia, and Mugilogobius chulae were exposed to 0.63-6.25, 0.63-10, and 1.25-20% concentrations of wash water, respectively. The 50% effective concentration in 96 h (EC₅₀-96 h) for D. salina was 2.48%, and the corresponding total polycyclic aromatic hydrocarbons (PAHs) and heavy metals were 22.81 and 23.67 μg L^-1. The 50% lethal concentration in 7 d (LC₅₀-7 d) values for M. bahia and M. chulae were 3.57% and 20.50%, respectively. The lowest observed effect concentration (LOEC) values for M. bahia and M. chulae were 1.25% and 2.5%, respectively, and the corresponding total PAHs and heavy metals were 11.50 and 11.93 and 22.99 and 23.86 μg L^-1. M. bahia's body weight was negatively correlated with the amount of wash water. Low concentrations of wash water (0-5%) had no significant effect on the reproduction of M. bahia. Although concentrations of 16 PAHs and 8 heavy metals are known, different compounds might react with each other and form more unknown toxic substances, and the measured toxicity comes from synergistic effects between various pollutants. Therefore, future work is needed to clarify other more toxic contaminants in wash water. We highly recommend that wash water be treated before being discharged to the marine environment.

Exposure to numerous pollutants is prevalent in workplaces. Examination of combined exposure to different harmful physical factors and chemicals has offered new insights into toxicology in recent years. This study aimed to investigate the hematological alterations caused by exposure to noise and toluene. Twenty-four New Zealand white rabbits were exposed to 1000 ± 50 ppm toluene and/or 100 ± 5 dB noise for 14 consecutive days. Exposure to noise and toluene changed a number of parameters of white blood cells (WBC), red blood cells (RBC), and platelets on different days after the exposure. Simultaneous exposure to noise and toluene increased WBC, and exposure to noise and toluene alone decreased RBC. Exposure to noise and toluene alone increased basophile, monocyte, and neutrophil counts. The coefficient of variation of red blood cell distribution width (RDW-CV) and the standard deviation of red blood cell distribution width (RDW-SD) significantly increased after co-exposure to noise and toluene. Platelet levels increased in the noise-exposed and the co-exposed groups and decreased in the toluene-exposed group. Furthermore, co-exposure to noise and toluene induced dissimilar synergistic and antagonistic effects on the hematological indices. According to the results of this study, simultaneous exposure to toluene and noise can aggravate some hematotoxic effects compared to exposure to noise or toluene alone. The results also demonstrated the vital role of the modulatory mechanisms of the body in controlling the detrimental effects of stressors.

Cardiovascular diseases (CVD) are a common global cause of death and are therefore a major health concern. Inhaled or ingested environmental heavy metals contribute to the development of CVD. The aim of this study was to address the limited information available on the effect of relevant dosages of metals in mixtures. Three metals with reported effects on the cardiovascular system (CVS) were identified, and these metals were copper (Cu), manganese (Mn) and mercury (Hg). In Sprague-Dawley rats, the adverse effects of copper (Cu), manganese (Mn) and mercury (Hg), alone and as part of mixtures, on the blood parameters, the aorta and heart were investigated. Forty-eight male Sprague-Dawley rats were randomly divided into eight groups (n = 6): control, Cu, Mn, Hg, Cu + Mn, Cu + Hg, Mn + Hg and Cu, Mn + Hg. The seven experimental groups received the metal mixtures at 100 times the World Health Organisation (WHO) safety limit for drinking water (2 mg/L for Cu, 0.4 mg/L for Mn and 0.06 mg/L for Hg) via oral gavage for 28 days. After 28 days, compared with the control, red blood cell levels were increased for Cu + Hg. All other measured blood parameters were unchanged. Morphological changes in the tunica media were connective tissue deposition and an abundance of collagen type I in the metal exposed aortic tissues. In the cardiac tissue of metal-exposed rats, changes in the cardiomyocyte and myofibrillar arrangement, with an increase in collagen type I and III was observed. Ultrastructurally, the aortic collagen and elastin band arrangement and the cardiac mitochondrial and myofibrillar arrangement and structures were altered in the experimental groups. These changes indicated that exposure to these metals in rats caused minor changes in the blood parameters, however, the changes in tissue and cellular structure indicated an increased risk for the development of CVD.