Single Exposure Group Research Articles

Risk of Opioid Overdose Associated with Concomitant Use of Methadone and Statins.

Methadone has a high potential for risky drug-drug interactions that can lead to opioid overdose, yet evidence on the magnitude of this risk remains limited. Since methadone is transported via P-glycoprotein (P-gp), the use of statins that inhibit P-gp may elevate methadone plasma concentrations, potentially leading to opioid overdose. We explored this hypothesis by examining whether concomitant use of methadone and P-gp-inhibiting statins was associated with opioid overdose. Using Medicaid claims data from 2003 to 2020, we conducted a cohort study among new concomitant users of methadone and statins. We compared overdose rates among individuals exposed to P-gp-inhibiting statins (simvastatin, atorvastatin, or lovastatin) vs. those exposed to rosuvastatin (negative control), adjusting for baseline covariates. We identified 69,263 individuals newly exposed to methadone and a statin of interest; the overall incidence rate of opioid overdose was 26.0 per 1,000 person-years. Adjusted hazard ratios (HRs) for methadone + P-gp-inhibiting statins consistently showed no association, ranging from 0.76 (95% CI = 0.48-1.22) for atorvastatin to 0.78 (95% CI = 0.50-1.22) for simvastatin, compared with methadone + rosuvastatin. Similar results were observed in sensitivity analysis that treated all P-gp-inhibiting statins as a single exposure group, as well as analyses stratified by baseline diagnosis of opioid use disorder or overdose, the duration of baseline methadone use, and calendar year intervals. Our findings suggest that concomitant use of methadone with simvastatin, atorvastatin, or lovastatin is not associated with the risk of opioid overdose compared to concomitant use of methadone and rosuvastatin.

Synergistic toxic effects of copper sulfate and trichlorfon on the health and intestinal microbiota of gibel carp Carassius auratus gibelio

In the high-density pond aquaculture of gibel carp (Carassius auratus gibelio) in China, copper sulfate (CuSO4) and trichlorfon (Tri) are commonly used, either in combination or alternately, to prevent and control various diseases and harmful algae. Despite their widespread use, there is a lack of studies on the toxic effects of CuSO4 and Tri on gibel carp, particularly regarding their combined application. This study assessed the effects of exposure to CuSO4 (0.5 mg/L) and Tri (0.5 mg/L), both individually and in combination, on gibel carp over 21 days. Histopathological assessments revealed significant structural damage to the liver and intestines in gibel carp exposed to either CuSO4 or Tri alone, with co-exposure notably intensifying these effects. Analysis of antioxidant enzyme activities revealed a substantial reduction in the liver and intestines, concurrent with a significant rise in the oxidative stress marker malondialdehyde in both single and combined exposure groups. Moreover, quantitative PCR analyses indicated a downregulation of immune-related genes post-exposure, with the combined treatment causing more severe suppression. This suppressed immune response correlated with a reduced ability to resist infection by the pathogenic bacterium Aeromonas hydrophila, particularly in the combined exposure group. This indicates that long-term exposure to CuSO4 and Tri, particularly in combination, induces significant oxidative stress damage in the liver and intestinal tissues, suppresses immune function, and reduces disease resistance. Additionally, 16S rRNA sequencing of the intestinal microbiota revealed that CuSO4 and Tri exposure altered the diversity and composition of intestinal microbial communities, potentially bringing both benefits and drawbacks. These findings underscore the need for careful management of CuSO4 and Tri in aquaculture to mitigate their adverse impacts, especially when used in combination for an extended period.

Neurobehavioral toxicity induced by combined exposure of micro/nanoplastics and triphenyltin in marine medaka (Oryzias melastigma)

Microplastics/nanoplastics (MNPs) inevitably coexist with other pollutants in the natural environment, making it crucial to study the interactions between MNPs and other pollutants as well as their combined toxic effects. In this study, we investigated neurotoxicity in marine medaka (Oryzias melastigma) exposed to polystyrene micro/nanoplastics (PS-MNPs), triphenyltin (TPT), and PS-MNPs + TPT from physiological, behavioral, biochemical, and genetic perspectives. The results showed that marine medaka exposed to 200 ng/L TPT or 200 μg/L PS-NPs alone exhibited some degree of neurodevelopmental deficit, albeit with no significant behavioral abnormalities observed. However, in the PS-MP single exposure group, the average acceleration of short-term behavioral indices was significantly increased by 78.81%, indicating a highly stress-responsive locomotor pattern exhibited by marine medaka. After exposure to PS-MNPs + TPT, the swimming ability of marine medaka significantly decreased. In addition, PS-MNPs + TPT exposure disrupted normal neural excitability as well as activated detoxification processes in marine medaka larvae. Notably, changes in neural-related genes suggested that combined exposure to PS-MNPs and TPT significantly increased the neurotoxic effects observed with exposure to PS-MNPs or TPT alone. Furthermore, compared to the PS-MPs + TPT group, PS-NPs + TPT significantly inhibited swimming behavior and thus exacerbated the neurotoxicity. Interestingly, the neurotoxicity of PS-MPs was more pronounced than that of PS-NPs in the exposure group alone. However, the addition of TPT significantly enhanced the neurotoxicity of PS-NPs compared to PS-MPs + TPT. Overall, the study underscores the combined neurotoxic effects of MNPs and TPT, providing in-depth insights into the ecotoxicological implications of MNPs coexisting with pollutants and furnishing comprehensive data.

Isoflurane conditioning improves functional outcomes after peripheral nerve injury in a sciatic cut repair murine model.

Anesthetic conditioning has been shown to provide neuroprotection in several neurological disorders. Whether anesthetic conditioning provides protection against peripheral nerve injuries remains unknown. The aim of our current study is to investigate the impact of isoflurane conditioning on the functional outcomes after peripheral nerve injury (PNI) in a rodent sciatic nerve injury model. Adult male Lewis rats underwent sciatic nerve cut and repair and exposed to none (Group 1, sham), single isoflurane exposure (Group 2), three-time isoflurane exposure (Group 3), and six-time isoflurane exposure (Group 4). Isoflurane conditioning was established by administration of 2% isoflurane for 1 hour, beginning 1-hour post sciatic nerve cut and repair. Groups 3 and 4 were exposed to isoflurane for 1 hour, 3 and 6 consecutive days respectively. Functional outcomes assessed included compound muscle action potential (CMAP), evoked muscle force (tetanic and specific tetanic force), wet muscle mass, and axonal counting. We observed an increase in axons, myelin width and a decrease in G-ratio in the isoflurane conditioning groups (3- and 6-days). This correlated with a significant improvement in tetanic and specific tetanic forces, observed in both groups 3 and 4. Isoflurane conditioning (3- and 6-day groups) resulted in improvement in functional outcomes at 12 weeks post peripheral nerve injury and repair in a murine model. Future experiments should be focused on identifying the therapeutic window of isoflurane conditioning and exploring the underlying molecular mechanisms responsible for isoflurane conditioning induced neuroprotection in PNI.

Exposure to bisphenol A and fiber-type microplastics induce oxidative stress and cell damage in disk abalone Haliotis discus hannai: Bioaccumulation and toxicity

Along with environmental pollution caused by rapid economic development and industrialization, plastic waste is emerging as a global concern in relation to marine ecosystems and human health. Among the microplastics, fiber-type microfibers (MF) and bisphenol A (BPA), which are widely used as plasticizers, do not decompose well in the ocean, and tend to accumulate in organisms, generating an increased oxidative stress response. This study investigated the abalones’ antioxidant and cell death responses following exposure to the environmental pollutants MF and BPA. Levels of malondialdehyde (MDA) and DNA damage increased over time, demonstrating the degree of lipid peroxidation and DNA damage in abalones exposed to individual and combined environmental conditions of MF and BPA. Compared to the single MF and BPA exposure groups, the combined exposure group showed a higher expression of antioxidant enzymes. A similar pattern was seen in the expression of the apoptosis enzyme caspase-3. Both MF and BPA caused oxidative stress and antioxidant enzymes were expressed to alleviate it, but it is believed that cell damage occurred because the stress level exceeded the allowed range.

Single and combined neurotoxic, cytotoxic and genotoxic effects of 5GHz MIMO waves and computed tomography irradiation in male Wistar rats

ABSTRACT A significant public concern is how technologies that emit electromagnetic waves interact and affect the biota because they are linked to the dysregulation of genes involved in neurotransmission, oxidative stress, and normal cellular function. Standard methods have been used to study how the combination of electromagnetic waves from 5 GHz radio and computed tomography (CT) irradiation affects whole blood parameters, neurobehavioural profiles, genomic DNA, and p53 gene expression in Wistar rats grouped into five, namely, I-Negative control, II-sham, III-5 GHz only, IV-5 GHz + CT, V-CT. The 5 GHz router was connected to the internet using an ethernet cable and the specific absorbance rate (SAR) was measured as 0.54W/kg and 24 V/0.5A power density, while CT parameters were set at 140 K.v, 300 mA, 5.3 cv at a 1.0-s speed for 60 s. Genomic DNA was isolated from rats’ cerebral cortex, while target gene and internal control primers (GAPDH) were synthesized for tumor suppressor (p53) gene expression and electrophoresed on a 1.2% agarose gel. We found that CT irradiation had gross effects on platelets, white blood cell counts, memory, hepatic and testicular histoarchitectures compared to the 5 GHz-only group. However, there was a loss of p53 (exons 5–7) gene bands in electrophoresed data with increased micronucleated polychromatic erythrocyte count in the 5 GHz group. Regardless of the interferential interaction in the combination group, the deleterious effects of non-ionizing and ionizing irradiation in the single and combined exposure groups predict functional abnormalities and dysregulated cellular processes from high electromagnetic fields exposure in biological systems.

Hygienic and Morphological Aspects of Using the Aqueous Solution of Molecular Hydrogen in an Experimental Model of Hay Fever

Introduction: The human body is exposed to numerous chemical and biological environmental factors. Post-exposure allergic reactions are becoming increasingly common. Interacting substances enhance each other’s health effects and aggravate allergy symptoms. Registration of a high pollen count resulting from a gradual increase in ambient temperatures leads to disappointing forecasts of a high prevalence of allergic rhinitis (hay fever). Evaluation of public health monitoring data on drinking water and food quality has revealed the significance of such pollutants as nitrates and nitrites. The interaction between pollen and nitrates has not been studied although it is of interest in terms of potential health effects of combined exposures. Objectives: To evaluate morphological changes in the quantitative composition of mast cells using an aqueous solution of molecular hydrogen in an experimental model of hay fever aggravated by exposure to chemical agents. Methods: Male Wistar rats were selected for experimental modeling of allergic rhinitis and 34 groups of six animals each were exposed to pollen and chemical agents during 55 days. To assess morphological changes in the nasal respiratory mucosa, we stained tissues with Giemsa solution and also applied a combined staining technique (Patent No. 2781558 dated October 13, 2022). Study limitations: Groups for comparison of methods of administration of the aqueous solution of molecular hydrogen against the saline solution were not included. Results: The cell morphology analysis revealed quantitative and qualitative changes in the animal groups with single and combined exposure to pollen and chemical agents and confirmed the therapeutic and prophylactic effect of the aqueous solution enriched with molecular hydrogen. Conclusion: The combined exposure to pollen allergens and nitrates and/or nitrites induces significant mast cell activation compared to control and single exposure groups. Therapeutic and preventive effects of molecular hydrogen down-regulate mast cell degranulation.

Co-exposure to lead, mercury, and cadmium induces neurobehavioral impairments in mice by interfering with dopaminergic and serotonergic neurotransmission in the striatum.

Humans are exposed to lead (Pb), mercury (Hg), and cadmium (Cd) through various routes, including drinking water, and such exposure can lead to a range of toxicological effects. However, few studies have investigated the toxic effects of exposure to mixtures of metals, particularly in relation to neurotoxicity. In this study, 7-week-old male mice were exposed to Pb, Hg, and Cd individually or in combination through their drinking water for 28 days. The mice exposed to the metal mixture exhibited significantly reduced motor coordination and impaired learning and memory abilities compared to the control group and each of the single metal exposure groups, indicating a higher level of neurotoxicity of the metal mixture. The dopamine content in the striatum was significantly lower in the metal mixture exposure group than in the single metal exposure groups and the control group. Furthermore, compared to the control group, the metal mixture exposure group showed a significantly lower expression level of tyrosine hydroxylase (TH) and significantly higher expression levels of dopamine transporter (DAT), tryptophan hydroxylase 1 (TPH1), and serotonin reuptake transporter (SERT). Notably, there were no significant differences in SERT expression between the single metal exposure groups and the control group, but SERT expression was significantly higher in the metal mixture exposure group than in the single metal and control groups. These findings suggest that the key proteins involved in the synthesis and reuptake of dopamine (TH and DAT, respectively), as well as in the synthesis and reuptake of serotonin (TPH1 and SERT, respectively), play crucial roles in the neurotoxic effects associated with exposure to metal mixtures. In conclusion, this study demonstrates that simultaneous exposure to different metals can impact key enzymes involved in dopaminergic and serotonergic neurotransmission processes, leading to disruptions in dopamine and serotonin homeostasis and consequently a range of detrimental neurobehavioral effects.

H - 32 Elevated Neurobehavioral Symptoms Detected in Greater Lifetime Subconcussive Exposure Frequency in Spanish-Speakers.

To examine whether individuals who have had one exposure to lifetime subconcussive impacts differ from those who have had multiple subconcussive exposures or those who have never had any injury to the head or neck in their report of neurobehavioral symptoms. 458 adults from the continental U.S., Spain, and Latin America participated in an online survey that included the Ohio State University Traumatic Brain Injury Identification Method Self- Administered-Brief (OSU TBI-ID SAB), which assesses lifetime exposure to Traumatic Brain Injury, and the Neurobehavioral Symptom Inventory (NSI), a measure of symptoms commonly observed after head injury. Questions from the OSU TBI-ID SAB allow for categorization of a No Exposure group, and Single and Multiple Subconcussive Exposure groups. General linear models were fitted with NSI scores as the dependent variable and the exposure groups as the independent variable. Sex, current age, and other central nervous system compromise were covariates. A significant Group difference with small effect size was found F(2,452) = 9.3, p < 0.001, ηp2 = 0.40. The Multiple Exposure group scored significantly higher on the NSI versus the Single Exposure (p = 0.004) and No Exposure (p < 0.001) groups. The Single Exposure group did not differ significantly from the No Exposure group (p = 0.084). The Spanish OSU TBI-ID SAB is sensitive to differentiating cumulative subconcussive exposures from those with only one subconcussive exposure and those with none. These data support the feasibility of deriving a subconcussive exposure index from the OSU TBI-ID SAB, and also provide preliminary justification for inclusion of a neurobehavioral symptom measure in subconcussive research and clinical practice.

TBBPA and lead co-exposure induces grass carp liver cells apoptosis via ROS/JAK2/STAT3 signaling axis

Tetrabromobisphenol A (TBBPA) and lead (Pb) are widely used in industrial field, which poses a serious threat to human and animal health. In particular, a large volume of wastewater containing TBBPA and Pb was discharged into the aquatic environment, causing a seriously negative impact on fish. Currently, whether TBBPA and Pb have a synergistic toxicity on fish remains unclear. In this study, we used the grass carp hepatocytes (L8824 cell line) exposed to either TBBPA or Pb, or both to determine their potential impacts on fish. The results showed that Pb or TBBPA induced oxidative stress and the loss of mitochondrial membrane potential in grass carp hepatocytes. In contrast to the control cells, the levels of JAK2, p-JAK2, STAT3 and p-STAT3 were significantly upregulated after exposure to TBBPA and Pb. Furthermore, the levels of Caspase3, Caspase9 and Bax were all increased while the level of Bcl2 was decreased in hepatocytes exposed to TBBPA or Pb. Results of flow cytometry and AO/EB staining reveled significant increases in the number of apoptotic cells in the TBBPA and Pb group compared to the controls. Notably, cells exposed to both TBBPA and Pb exhibited more severe damage than the single exposure, manifested by a higher number of apoptotic cells in the co-exposure group than the single exposure groups. Nevertheless, N-acetyl-l-cysteine (NAC) treatment could remarkably alleviate oxidative damage and loss of membrane potential in grass carp hepatocytes induced by TBBPA and Pb. Altogether, our study showed that combined exposure of TBBPA and Pb has a synergistic toxicity due to, inducing oxidative stress to activate JAK2/STAT3 signaling pathway, resulting in apoptosis of carp hepatocytes. This study shed a new light on the toxicological mechanism of exposure of TBBPA and Pb and provided a potential treatment of toxicity induced by TBBPA and Pb.

Study on toxicity responses and their mechanisms in Xenopus tropicalis long-term exposure to Shigella flexneri and ciprofloxacin

The abuse and overuse of antibiotics increased not only the exposure of aquatic animals to antibiotics but also the development of resistance in pathogenic bacteria. To investigate the effects and mechanisms of exposure, a long-term experiment lasting 120 days was conducted in which Xenopus tropicalis was exposed to single and combined stress factors of multiresistant pathogenic Shigella flexneri and ciprofloxacin (CIP). The intestinal oxidative stress, immune factors and flora, as well as the brain-gut axis correlation factors of X. tropicalis, were tracked to account for the response of aquatic animals to the exogenous pollutants. SOD activity and MDA content were significantly increased in stressed X. tropicalis (p < 0.001), while the levels of proinflammatory factors (IL-1β, IFN-γ) were significantly reduced (p < 0.01). The content of intestinal beneficial bacteria decreased and that of harmful bacteria increased in the intestinal flora of the stressed X. tropicalis (p < 0.001). These results suggested that S. flexneri and CIP disturbed the intestinal flora and caused oxidative damage in the host, and the body produced a series of responses, such as oxidative stress responses and regulation of the expression of immune factors, to maintain the balance of antioxidant inflammation. Significant changes in the expression of intestinal neurotransmitters (5-HT, CGRP) and brain peptides (BDNF, NCAM, NPY) (p < 0.05) also indicated that the brain-gut axis interaction was disrupted. In addition, although the coexisting CIP could reduce intestinal toxicity caused by S. flexneri, the amount of intestinal pathogenic bacteria Desulfovibrio increased significantly. Moreover, compared with the single exposure group, SOD activity, CAT activity and MDA content were significantly reduced in the dual exposure group. Therefore, the health risks of multiresistant pathogenic bacteria on the intestinal and brain-gut axis interaction should be given more attention, and the interaction of brain-gut axis is more important when antibiotics coexist.

Ecological toxicity of microplastics, aluminum and their combination to ectomycorrhizal fungi (Lactarius delicious)

&lt;p&gt;To investigate the combined toxic effects of microplastics and aluminum (Al) on ectomycorrhizal fungi, Lactobacillus delicious (Ld) was selected as the experimental subject to conduct research on monodisperse polystyrene microplastics (PS-MPs) (0, 20, 100, 200 mg L-1) and Al3+ (40 mg L-1) single pollution on Ld growth, the antioxidant system and organic acid secretion, followed by their combined effect. The results showed that the growth of Ld was inhibited and the biomass decreased significantly (P &amp;lt; 0.05) under single exposure to PS-MPs or Al3+, and the contents of superoxide anion radical (O2·-) and H2O2 in mycelia increased significantly (P &amp;lt; 0.05). Meanwhile, superoxide dismutase (SOD) and peroxidase (POD) activities were also significantly increased (P &amp;lt; 0.05), while catalase (CAT) activity was significantly decreased (P &amp;lt; 0.05), indicating that PS-MPs or Al3+ stress had different effects on antioxidant enzyme activities in Ld mycelia, which used highly active antioxidant enzymes to eliminate excess reactive oxygen species (ROS) and maintain their dynamic balance. In addition, the electrolyte leakage rate, proline and malondialdehyde (MDA) contents in Ld mycelia were significantly increased (P &amp;lt; 0.05). Under the combined exposure of PS-MPs and Al3+, compared with the control group, the combined exposure of high concentrations of PS-MPs and Al3+ (200+40 mg L-1) had a certain promoting effect on the biomass of Ld. In addition, the O2·-, H2O2, electrolyte leakage rate and malondialdehyde content in Ld mycelia increased significantly (P &amp;lt; 0.05), but these indices were significantly lower than those in the single PS-MPs exposure group at the same concentration. This indicates that the combined effect of PS-MPs and Al3+ could reduce the damage of single pollutants to the Ld biomass membrane and reduce the production of ROS to a certain extent. In addition, correlation analysis showed that H2O2 in Ld mycelia had a highly significant positive correlation with the oxalic acid and total hydrogen ion concentrations in the culture solution (P &amp;lt; 0.01). This indicates that strain Ld could respond to the oxidative damage caused by microplastics and Al by secreting oxalic acid and hydrogen ions into the culture medium.&lt;/p&gt;&#x0D;

Impacts of exposure to nanopolystyrene and/or chrysene at ambient concentrations on neurotoxicity in Siniperca chuatsi

Health risks caused by widespread environmental pollutants such as nanopolystyrene (NP) and chrysene (CHR) in aquatic ecosystems have aroused considerable concern. The present study established juvenile Mandarin fish (Siniperca chuatsi) models of NP and/or CHR exposure at ambient concentrations for 21 days to systematically investigate the underlying neurotoxicity mechanisms. The results showed that single and combined exposure to NP and CHR not only reduced the density of small neuronal cells in the grey matter layer of the optic tectum, but also induced brain oxidative stress according to physiological parameters including CAT, GSH-Px, SOD, T-AOC, and MDA. The co-exposure alleviated the histopathological damage, compared to NP and CHR single exposure group. These results indicate that NP and/or CHR causes neurotoxicity in S. chuatsi, in accordance with decreased acetylcholinesterase activity and altered expression of several marker genes of nervous system functions and development including c-fos, shha, elavl3, and mbpa. Transcriptomics analysis was performed to further investigate the potential molecular mechanisms of neurotoxicity. We propose that single NP and co-exposure induced oxidative stress activates MMP, which degrades tight junction proteins according to decreased expression of claudin, JAM, caveolin and TJP, ultimately damaging the integrity of the blood-brain barrier in S. chuatsi. Remarkably, the co-exposure exacerbated the blood-brain barrier disruption. More importantly, single NP and co-exposure induced neuronal apoptosis mainly activates the expression of apoptosis-related genes through the death receptor apoptosis pathway, while CHR acted through both death receptor apoptosis and endoplasmic reticulum apoptosis pathways. Additionally, subchronic CHR exposure caused neuroinflammation, supported by activation of TNF/NF-κB and JAK-STAT signaling pathways via targeting-related genes, while the co-exposure greatly alleviated the neuroinflammation. Collectively, our findings illuminate the underlying neurotoxicity molecular mechanisms of NP and/or CHR exposure on aquatic organisms.

Role of Cx43 in iPSC-CM Damage Induced by Microwave Radiation.

The heart is one of the major organs affected by microwave radiation, and these effects have been extensively studied. Previous studies have shown that microwave-radiation-induced heart injury might be related to the abnormal expression and distribution of Cx43. In order to make the research model closer to humans, we used iPSC-CMs as the cell injury model to investigate the biological effect and mechanism of iPSC-CM injury after microwave radiation. To model the damage, iPSC-CMs were separated into four groups and exposed to single or composite S-band (2.856 GHz) and X-band (9.375 GHz) microwave radiation sources with an average power density of 30 mW/cm2. After that, FCM was used to detect cell activity, and ELISA was used to detect the contents of myocardial enzymes and injury markers in the culture medium, and it was discovered that cell activity decreased and the contents increased after radiation. TEM and SEM showed that the ultrastructure of the cell membrane, mitochondria, and ID was damaged. Mitochondrial function was aberrant, and glycolytic capacity decreased after exposure. The electrical conduction function of iPSC-CM was abnormal; the conduction velocity was decreased, and the pulsation amplitude was reduced. Wb, qRT-PCR, and IF detections showed that the expression of Cx43 was decreased and the distribution of Cx43 at the gap junction was disordered. Single or composite exposure to S- and X-band microwave radiation caused damage to the structure and function of iPSC-CMs, primarily affecting the cell membrane, mitochondria, and ID. The composite exposure group was more severely harmed than the single exposure group. These abnormalities in structure and function were related to the decreased expression and disordered distribution of Cx43.

Physiological effects and molecular response in the marine rotifer Brachionus plicatilis after combined exposure to nanoplastics and copper

Because nanoplastics (NPs) can transport pollutants, the absorption of surrounding pollutants into NPs and their effects are important environmental issues. This study shows a combined effect of high concentrations of NPs and copper (Cu) in the marine rotifer Brachionus plicatilis. Co-exposure decreased the growth rate, reproduction, and lifespan. The highest level of NP ingestion was detected in the co-treated group, but the Cu concentration was higher in the Cu single-exposure group. ERK activation played a key role in the downstream cell signaling pathway activated by the interaction of NPs and Cu. The increased sensitivity of B. plicatilis to Cu could be due to the impairment of MXR function caused by a high concentration of NPs, which supports our in vivo experiment results. Our results show that exposure to NPs could induce the dysfunction of several critical molecular responses, weakening resistance to Cu and thereby increasing its physiological toxicity in B. plicatilis.

Micro-polystyrene plastic and benzo[α]pyrene exposure affects the endocrine system and causes physiological stress in Carassius auratus

Microplastics, owing to their hydrophobic properties and the various chemicals used in their production, can act as carriers of persistent organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs). In this study, we exposed the goldfish Carassius auratus to benzo[α]pyrene (BaP, 10 μg/L), a representative PAH, and micro-polystyrene plastic (MP; 10 and 100 beads/L), of size 1.0 μm, as a single or complex environmental stressor, and evaluated the stress response and the resulting DNA damage. The expression of CRH and ACTH mRNA in the pituitary gland and hypothalamus, of the hypothalamus–pituitary–interrenal (HPI) axis, increased significantly after 6 h of exposure. Plasma cortisol levels showed a similar trend to the expression of stress-regulating genes along the HPI axis, and a significant increase was observed in the combined exposure groups (BaP + LMP [low-concentration MP] and BaP + HMP [high-concentration MP]) compared to those in the single exposure group. H2O2 concentration and CYP1A1 and MT mRNA expression levels in the liver were significantly higher in the combined exposure groups compared with in the single exposure groups. In situ hybridization revealed a similar pattern of MT mRNA expression, and many signals were observed in the BaP + HMP group. Furthermore, the BaP + HMP group showed more DNA damage, and the degree of DNA damage increased with exposure time for all experimental groups, except for the control group. Therefore, exposure to BaP and MP alone can induce stress in goldfish; however, when a combination of both substances is provided, their synergistic effect leads to increased stress and DNA damage. MP was confirmed to be a more serious stress-inducing factor in goldfish than BaP, based on the expression levels of stress-regulating genes along the HPI axis.

Combined exposure to polystyrene nanoplastics and bisphenol A induces hepato- and intestinal-toxicity and disturbs gut microbiota in channel catfish (Ictalurus punctatus)

The widespread consumption of nanoplastics (NPs) and bisphenol A (BPA) affected the aquatic ecosystem and imposed risks to the safety of aquatic organisms. This study was aimed at assessing the ecotoxicological effects of single and combined exposure to BPA and polystyrene nanoplastics (PSNPs) on the channel catfish (Ictalurus punctatus). A total of 120 channel catfish were separated into four groups with triplicate (each contains 10 fish) and exposed to chlorinated tap water (control group), PSNP single exposure (0.3 mg/L), BPA single exposure (500 μg/L) and PSNPs (0.3 mg/L) + BPA (500 μg/L) co-exposure for 7 days. Our results showed a relatively higher intestinal accumulation of PSNPs in co-exposure group, compared to PSNP single exposure group. Histopathological analysis showed that single exposure to PSNPs and BPA caused breakage of intestinal villi and swelling of hepatocytes in channel catfish, while the co-exposure exacerbated the histopathological damage. In addition, co-exposure significantly increased SOD, CAT activities and MDA contents in the intestine and liver, inducing oxidative stress. In terms of immune function, the activities of ACP and AKP were significantly decreased. The expressions of immune-related genes such as IL-1β, TLR3, TLR5, hepcidin and β-defensin were significantly up-regulated, and the expression of IL-10 was down-regulated. Additionally, the co-exposure significantly altered the composition of the intestinal microbiota, leading to an increase in the Shannon index and a decrease in the Simpson index. In summary, this study revealed that mixture exposure to PSNPs and BPA exacerbated toxic effects on histopathology, oxidative stress, immune function and intestinal microbiota in channel catfish. It emphasized the threat of NPs and BPA to the health of aquatic organisms and human food safety, with a call for effective ways to regulate the consumption of these anthropogenic chemicals.

Insights into enhanced toxic effects by the binary mixture of carbendazim and procymidone on hepatic lipid metabolism in mice

Carbendazim (CBZ) and procymidone (PRO) are two widely used fungicides in agriculture. However, there are still gaps in knowledge regarding about the potential hazards of joint exposure to CBZ and PRO in animals. Here, 6-week-old ICR mice were exposed to CBZ, PRO and CBZ + PRO for 30 days, and metabolomics were performed to discover the mechanism by which the mixture enhanced the effects on lipid metabolism. Co-exposure to CBZ + PRO elevated the body weights, relative liver weights and relative epididymis fat weights, but not in the single exposure groups. Molecular docking analysis suggested that CBZ and PRO combined with peroxisome proliferator-activated receptor (PPARγ) at the same amino acid site as the agonist rosiglitazone. The RT-qPCR and WB results demonstrated that the levels of PPARγ were higher in the co-exposure group than in the single exposure groups. In addition, hundreds of differential metabolites were discovered by metabolomics and enriched in different pathways, such as pentose phosphate pathway and purine metabolism. A unique effect, a decrease in glucose-6-phosphate (G6P) that promoted more NADPH production, was observed in the CBZ + PRO group. These results demonstrated that exposure to CBZ + PRO caused more serious lipid metabolism disorder in the liver than exposure to a single fungicide, which could provide some new insight for the toxic effects after fungicides joint exposure.

Combined exposure to benzo(a)pyrene and dibutyl phthalate aggravates pro-inflammatory macrophage polarization in spleen via pyroptosis involving cathepsin B

Humans are often simultaneously exposed to benzo(a)pyrene (BaP) and dibutyl phthalate (DBP) through consumption of food and water. Yet, direct evidence of the link between BaP and DBP co-exposure and the risk of splenic injury is lacking. In the present study, we established the rats and primary splenic macrophages models to evaluate the effects of BaP or/and DBP exposure on spleen and underlying mechanisms. Compared to the single exposure or control groups, the co-exposure group showed more severe spleen damage and higher production of pro-inflammatory cytokines. Co-exposure to BaP and DBP resulted in a 1.79-fold, 2.11-fold and 1.9-fold increase in the M1 macrophage markers iNOS, NLRP3 (pyroptosis marker protein) and cathepsin B (CTSB), respectively, and a 0.8-fold decrease in the M2 macrophage marker Arg1 in vivo. The more prominent effects in perturbation of imbalance in M1/M2 polarization (iNOS, 2.25-fold; Arg1, 0.55-fold), pyroptosis (NLRP3, 1.43-fold), and excess CTSB (1.07-fold) in macrophages caused by BaP and DBP co-exposure in vitro were also found. Notably, MCC950 (the NLRP3-specific inhibitor) treatment attenuated the pro-inflammatory macrophage polarization and following pro-inflammatory cytokine production triggered by BaP and DBP co-exposure. Furthermore, CA-074Me (the CTSB-specific inhibitor) suppressed the macrophages pyroptosis, pro-inflammatory macrophage polarization, and secretion of pro-inflammatory cytokine induced by BaP and DBP co-exposure. In conclusion, this study indicates co-exposure to BaP and DBP poses a higher risk of spleen injury. Pro-inflammatory macrophage polarization regulated by pyroptosis involving CTSB underlies the spleen injury caused by BaP and DBP co-exposure.

Single and combined effects of cadmium, microplastics, and their mixture on whole-body serotonin and feeding behaviour following chronic exposure and subsequent recovery in the freshwater leech, Nephelopsis obscura

Microplastics and metals are contaminants detected in many freshwater systems globally. Interactions of microplastics with other contaminants including cadmium poses potential threats to the health of aquatic organisms including Nephelopsis obscura, a predatory leech species that is widespread and serves important ecological and economic roles. The feeding biology of N. obscura has been well-described, including that serotonin regulates feeding behaviour. Further, exposure to cadmium has been found to cause decrease whole-body concentrations of serotonin. The influence that microplastic contamination and co-contamination of cadmium and microplastics has on N. obscura is unknown. The present study had three objectives: (1) to determine if water or sediment contaminated with cadmium, microplastics, or their mixture resulted in greater cadmium uptake by N. obscura, (2) to assess effects of chronic (21-day) exposure of N. obscura to waterborne cadmium, microplastics, and their mixture on bioaccumulation of cadmium, concentrations of serotonin, and feeding behaviour (latency to feeding, time spent feeding, and distance moved), and (3) to reassess the bioaccumulation of cadmium, concentrations of serotonin, and feeding behaviour following transfer to an uncontaminated environment for a one-week recovery period. This study revealed that access to and presence of sediment is protective against cadmium uptake and that cadmium is more readily accumulated from waterborne sources, even in environments where both sediment and surface water are contaminated. After 21-days of exposure to waterborne cadmium, microplastics, and their mixture, accumulation of cadmium, decreased concentrations of serotonin, and impaired feeding behaviours were greatest in leeches from the co-exposures compared to leeches from either single contaminant exposure group. Finally, after one week of depuration and recovery in freshwater following the 21-day exposures, concentrations of serotonin and feeding behaviour were restored in individuals from the microplastic exposure; however, cadmium-exposed individuals continued to show decreased concentrations of serotonin and behavioural deficits. The co-exposure of leeches to cadmium and microplastics resulted in additive effects to serotonin synthesis and feeding behaviour; however, this study demonstrated that leeches were able to recover from microplastic toxicity within a week whereas cadmium toxicity persisted.