Histological changes, lipid metabolism and oxidative stress in the liver of Bufo gargarizans exposed to cadmium concentrations

Integrated transcriptomic and proteomic analysis of hepatotoxic effects of Venenum Bufonis in zebrafish

BACKGROUND

Venenum Bufonis (VB), a traditional Chinese medicine (TCM), is renowned for its therapeutic detoxification, pain relief, and cognitive enhancement effects. VB has been classified as a toxic TCM in medical literature, and its clinical usage is currently subject to several limitations. However, the toxicological characteristics of VB and underlying mechanisms remain unclear.

METHODS

We conducted a comprehensive assessment to confirm the target organs affected by VB using the zebrafish model. Subsequently, network pharmacology, transcriptomic and proteomic analyses were performed to explore the associated mechanisms, with the aim of providing a basis for its clinical application.

RESULTS

VB exhibited dose-dependent toxic effects on zebrafish, particularly causing gross morphological abnormalities in the liver along with aggravated hepatocyte apoptosis. Pericardial edema and an enlarged atrioventricular septum were also observed. The combined analyses revealed significant alterations induced by VB in gene expression enriched in multiple pathways and biological processes. Importantly, TLR4/RIPK2/NF-κB and Wnt signaling-mediated inflammation, fibrosis, and apoptosis were identified as the key functional signaling pathways underlying VB-mediated liver toxicity.

CONCLUSION

Our results present robust and direct evidence of the hepatotoxic effects induced by VB in zebrafish, while also providing novel insights into the molecular pathways involved. These results establish a solid theoretical foundation for the appropriate clinical application of VB.

High-yield extraction of long-chain fatty acids from Chlorella vulgaris: Comparative analysis of ozone extraction methods

The production of biodiesel using microalgae has emerged as a promising alternative to fossil fuel-derived energy. However, microalgae-based biodiesel still faces challenges in achieving commercial economic feasibility. One of the primary reasons for this challenge is the limited extraction yield of long-chain fatty acids (LCFAs), which are essential for biodiesel synthesis. This study explores an easily accessible ozone-based extraction method to maximize LCFAs yields to address limitations. The experiments were conducted using Chlorella vulgaris, and the extraction efficiency was assessed for single ozone treatment and the combination of ozone treatment with physical (ultrasound) and chemical (pH adjustment) methods. The results indicated that LCFAs yield (33.12 mg/g) was achieved at 5 mg/L ozone concentration for 15 min at neutral pH, which was 3.41 times higher than that of the control (9.71 mg/g). Furthermore, combining ozone treatment with 100 W of ultrasound further enhanced the LCFAs yield to 52.32 mg/g, demonstrating a synergistic effect between ozone and physical treatment. The mechanism behind the increased extraction efficiency was attributed to the weakening of the cell wall, which facilitated LCFAs extraction. Additionally, it was observed that endogenous lipid synthesis was enhanced when the antioxidant 2,4-di-tert-butylphenol (2,4-DTBP) was promoted in response to oxidative stress. The extracted LCFAs in this study were mainly saturated fatty acids, namely palmitic acid (C16:0) and stearic acid (C18:0). This study offers insights into optimizing ozone-based LCFA extraction as a scalable, eco-friendly method for microalgal biodiesel production, emphasizing its potential to reduce carbon dioxide emissions and support carbon-neutral energy solutions.

Ecosurveillance reveals subtle metabolic effects on the non-native cane toad (Rhinella marina) from low levels of accumulated environmental per- and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that persist in the environment, bioaccumulate, and may have toxic effects. This study used non-native cane toads (Rhinella marina) to examine PFAS and metal accumulation and impacts in large terrestrial amphibians from urban and peri-urban areas. We quantified 38 PFAS compounds and 36 environmental and legacy metal(loid)s in 52 adult cane toad livers collected from six locations around Southeast Queensland, Australia, along a known PFAS gradient. Associations among PFAS, metal(loid) concentrations, and whole-organism metrics were assessed. An omics-led approach assessed biochemical responses in liver, muscle, fat and gonad/egg tissues associated with these PFAS concentrations. Liver PFAS concentrations ranged from 0.5 to 82.1 μg/kg ww, with one male outlier at 452 μg/kg ww (mean: 18 ± 21 SD μg/kg ww, excluding outlier). PFOS was the most dominant PFAS (60 ± 26 SD% of total), followed by PFDoDA (13 ± 9 SD%). The liver metal(loid)s with statistically significant variation among locations and sex were Al, As, Ca, Cu, Mn, Ni, Se, Sn, Sr and V. Total PFAS had no associations with whole-organism metrics, and body condition and relative femur length showed a weak interaction effect between PFAS and Ni. Metabolic profiling revealed sex-specific differences linked to total PFAS, with females showing a broader metabolic perturbation. The strongest metabolic signals were in glycerolipid metabolism, ether lipid metabolism, and fatty acid biosynthesis, though these effects were statistically weak. PFAS and metal(loid) levels were low compared to those previously recorded in tertiary consumers and aquatic vertebrates from contaminated areas. Despite minor metabolomic changes, the overall health impact was minimal. These findings contribute to the development of tissue PFAS guideline values for wild amphibians, but further studies on higher PFAS levels of accumulation and responses of additional amphibian species are needed.

Differential Mitochondrial Genome Expression of Four Skink Species Under High-Temperature Stress and Selection Pressure Analyses in Scincidae

As ectotherms highly sensitive to environmental temperature fluctuations, skinks (a small lizard) are increasingly vulnerable to population instability due to global heatwaves. A clade model analysis of four Chinese skink species (Plestiodon capito, Plestiodon chinensis, Sphenomorphus indicus, and Scincella modesta) revealed positive selection acting on the ND6 gene in Sp. indicus. This species exhibits codon alterations in ND6, shifts its expression pathway and potentially decouples ND6 from high-temperature stress response mechanisms. To validate these findings, transcriptomic profiling was conducted to assess mitochondrial protein-coding gene (PCG) expression patterns under thermal stress. Using RT-qPCR, liver mitochondrial PCG transcript levels were compared between high-temperature (34 °C) and control (25 °C) groups in skink populations from distinct latitudes. Low-latitude species (P. chinensis and Sc. modesta) exhibited metabolic downregulation, characterized by a significant suppression of mitochondrial gene expression. Specifically, P. chinensis showed the downregulation of six mitochondrial genes (COII, COIII, ATP6, ND2, ND4, ND6) while upregulating one (ND1). By contrast, Sc. modesta showed the downregulation of nine genes (COI, COII, COIII, ATP8, ND1, ND3, ND4, ND4L, CYTB) and upregulated two (ND5, ND6). By contrast, high-latitude species exhibited divergent patterns: P. capito downregulated four genes (COI, COII, COIII, ND4L) and upregulated four others (ND1, ND2, ND3, ND4), whereas Sp. indicus downregulated six genes (COI, COII, ND2, ND3, ND4, ND4L) and upregulated one (ND5). These regulatory disparities suggest that low-latitude skinks have a greater capacity for metabolic depression to cope with chronic stress, whereas their high-latitude counterparts exhibit different adaptations. The findings provide valuable insights into assessing the adaptive potential of species in warming environments, particularly for ectotherms with limited thermoregulatory capacities.

Multiple biological responses and transcriptome plasticity of the model unicellular eukaryote paramecium for cadmium toxicity aggravated by freshwater acidification

Cadmium (Cd) pollution is a widespread threat to aquatic life, and ongoing freshwater acidification (FA) can be expected to interact with Cd compounds to disrupt freshwater ecosystems. However, the effects of FA on Cd biotoxicity remain unclear. Herein, the model ciliate Paramecium tetraurelia, a model unicellular eukaryotic organism, was used to explore the response to environmental relevant concentrations of Cd under acidification conditions. We show for the first time that exposure to acidified freshwater accelerated Cd bioaccumulation and enhanced Cd bioavailability in P. tetraurelia, suggesting the synergistic interaction of Cd and FA. The co-exposure greatly reduced the abundance and carbon biomass, altered lysosomal membrane stability, induced oxidative stress, and consumed more ATP in exposed ciliates. Transcriptome plasticity enabled P. tetraurelia to develop a Cd stress-adaptive transcriptional profile (upregulation of transport and detoxification and downregulation of energy metabolism) under acidification. With a concomitant inhibition in energy production, the exposed ciliates might have diverted the energy from growth and cell replication to compensate for the energetic cost from stress response and detoxification. Collectively, acidified freshwater could aggravate Cd toxicity, which, in turn, arouses the response strategy of ciliates to cope with stress, providing a mechanistic understanding of the interaction between freshwater acidification and Cd pollution in the basic trophic level ciliated protozoa in freshwater ecosystems.

Effect of glucose selenol on hepatic lipid metabolism disorder induced by heavy metal cadmium in male rats

This study used 24 male rats to determine the protective effects of a new selenium molecule (glucose selenol) on cadmium (Cd) induced hepatic toxicity. The rats were randomly divided into four groups: control group, Cd group, Cd + 0.15 Se group, and Cd + 0.4 Se group. The results showed that glucose selenol supplementation alleviated the adverse impact of Cd on lipid metabolism, including decreased serum triacylglycerol and cholesterol levels. Transcriptome analysis revealed that, compared to the control group, Cd changed the expression of 1379 genes - discernibly affecting lipid metabolism pathways. Proteomic analysis primarily indicated alterations in lipid metabolism-related pathways. In conclusion, glucose selenol restored lipid metabolism disorders induced by Cd, thus rescuing hepatic damage. This integrated analysis identified the influence of glucose selenol on Cd-induced hepatic toxicity and provided its potential application prospects in alleviating the impact of heavy metal pollution, such as Cd, on human health.

Effects of Exposure to Different Types of Microplastics on the Growth and Development of Rana zhenhaiensis Tadpoles

Microplastic (MP) pollution is a major environmental problem, but a comparative study of the toxicological effects of different MPs remains lacking. To explore the toxicological effects of three different microplastics, namely, polypropylene (PP), polystyrene (PS) and polyethylene (PE), Zhenhai brown frog (Rana zhenhaiensis) tadpoles were used as the model animal. The results showed that exposure to PE and PS significantly reduced the metamorphosis rate of the tadpoles. Compared with the control group, the body weight of tadpoles in all MP treatments was significantly reduced compared with that of the control group. In addition, exposure to PE reduced the body length and hind limb length of tadpoles. The number of pigment cells increased and intercellular spaces expanded in the liver tissues of tadpoles receiving PS and PE treatments. The composition and function of the intestinal microbiota in the PP treatment and control groups were similar, whereas between the PS treatment and control, they differed. Liver transcriptome sequencing revealed significant alterations in key genes associated with oxidative stress, energy metabolism, immune response, and apoptosis signaling pathways with PS treatment and PP treatment. In summary, MPs may have harmed tadpoles to varying degrees by interfering with related signaling pathways. The negative effects of PE and PS were greater than those of PP.

Integrative oxidative stress biomarkers in gills and digestive gland of the combined exposure to citalopram and bezafibrate with polyethylene microplastics on mussels Mytilus galloprovincialis

Pharmaceutical active compounds (PhACs) and microplastics (MPs) have been detected in different marine compartments from coastal areas, raising concerns due to their simultaneous discharge through wastewater treatment plants (WWTPs) and the role of MPs as vectors of pollutants for marine organisms. This study investigates the biochemical effects of citalopram (CIT) and bezafibrate (BEZ) on the mussel Mytilus galloprovincialis, at environmentally relevant concentrations, and their co-exposure with high-density polyethylene (HDPE) MPs. MPs accumulated in gills and digestive glands during exposure, but they were rapidly eliminated after depuration, except for a small fraction of the smallest MPs in gills. This study evaluated the biological effects in gills and digestive gland, and confirmed CIT induced oxidative stress in both tissues, exacerbated by the presence of MPs. BEZ, despite not being detected at high concentrations in the mussel tissues, activated an antioxidant response in gills and increasing the transcription of the genes Se-gpx and gst-pi in digestive gland. Both PhACs impaired the cholinergic pathway long-term, even after the depuration period, as indicated by decreased AChE levels in the gills, suggesting potential neurotoxic effects after prolonged exposure. Consequently, adverse effects were provoked by both PhACs with (CIT) and without (BEZ) significant bioaccumulation capacity.

CPT1 deficiency blocks autophagic flux to promote lipid accumulation induced by co-exposure to polystyrene microplastic and cadmium

Introduction

Cadmium (Cd) and polystyrene microplastics (PS-MPs), two ubiquitous environmental contaminants, produce unique synergistic toxicity when co-existing. Key unanswered questions include specific effects on liver function and potential mechanisms.

Methods

In this study, C57BL/6 mice and AML12 cells were used to establish in vivo and in vitro models to elucidate the effects of combined exposure to PS-MPs and Cd on the liver and their mechanisms.

Results

The results showed that the combined effects of PS-MPs and Cd caused significantly more liver damage than exposure alone. As observed by transmission electron microscopy (TEM), the number of autophagosomes was significantly increased in the PS-MPs and Cd co-treated group. In addition, autophagic flux was assayed by RFP-GFP-LC3, a reporter system expressing dual fluorescent proteins, which showed an overwhelming enhancement of autophagic flux damage by co-exposure to PS-MPs and Cd compared to exposure alone. To further investigate the involvement of carnitine palmitoyltransferase1(CPT1) in liver injury induced by co-exposure to Cd and PS-MPs, we co-exposed Baicalin, an activator of CPT1, with PS-MPs and Cd, and showed that activation of CPT1 alleviated the impairment of autophagic fluxes induced by co-exposure of Cd and PS-MPs and further alleviated the changes in lipid accumulation and associated protein levels.

Discussion

In conclusion, the concurrent exposure of PS-MPs and Cd resulted in the blockage of hepatic lipid accumulation and autophagic pathway and further aggravated the toxic damage to the liver. Activation of CPT1 could alleviate the PS-MPs and Cd-induced lipid accumulation and autophagy pathway blockage thus reducing liver injury.

Preparation for oxidative stress in Chinese toads (Bufo gargarizans) living under natural conditions along an altitudinal gradient

Preparation for oxidative stress (POS) has been widely reported in animals under controlled laboratory conditions, but whether this phenomenon is visible in animals under natural conditions remains to be explored. Altitudinal gradients provide a good opportunity to address this question, since environmental conditions become more hostile with increasing altitude. Here, we investigated the levels of oxidative stress, oxidative damage, and antioxidant defenses in Chinese toads (Bufo gargarizans) along an altitudinal gradient (50 m, 1200 m, 2300 m, 3400 m above sea level). The results show that changing altitude led to a significantly lower ratio of oxidized to reduced glutathione in liver, with a higher value at 50 m. This ratio in muscle tissues did not differ significantly between altitudes of 50 m, 2300 m, and 3400 m. However, reduced glutathione content increased significantly along the altitude, with higher values in liver at 2300 m and higher values in skeletal muscle at 3400 m. Malondialdehyde (MDA) content in liver did not change significantly with increasing altitude. Brain and muscle tissues showed a higher MDA content at 50 m than the other three altitudes. The activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase, as well as total antioxidant capacity, also displayed tissue-specific upregulation in heart, skeletal muscle, and brain, but all of these antioxidant enzymes except for glutathione-S-transferase were significantly reduced in liver along the altitudinal gradient. In summary, environmental factors at higher altitude did not lead to higher levels of oxidative stress and oxidative damage in B. gargarizans, mainly due to stronger antioxidant defenses. This study corroborates the occurrence of POS in high-altitude toads living under field conditions and contributes to revealing the biochemical adaptations to extreme environments at higher altitude.

Hepatocyte-Specific Yap1 Knockout Maintained the Liver Homeostasis of Lipid Metabolism in Mice

Introduction

Yes-associated protein 1 (YAP1) is a crucial molecule in the Hippo pathway. The impact of hepatocyte-specific Yap1 knockout (Yap1 LKO) on hepatic lipid droplets (LD) and pePLIN2 in metabolic fatty liver has not been reported. This study aims to explore whether Yap1 LKO could offer a protective effect in a liver injury model.

Methods

Three-week-old Yap1 LKO and Yap1 Flox mice were given aristolochic acid I (AAI) combined carbon tetrachloride (CCL4) establish liver injury model. Eight-week-old Yap1 LKO and Yap1 Flox mice were fed with a high-fat diet for 18 weeks to establish obesity-related liver injury model. Further biochemical, histomorphological, immunohistochemical, and lipidomic analyses were performed on serum and liver tissues of these mice to elucidate the effects of hepatocyte-specific Yap1 knockout on hepatic lipid metabolism.

Results

Yap1 LKO reduced triglyceride (TG) content and PLIN2 expression level in the liver during the intervention of AAI combined CCl4. Moreover, Yap1 LKO improved lipid metabolism homeostasis in the liver by increasing the beneficial lipid molecules and reducing the harmful lipid molecules through lipidomics. Finally, Yap1 LKO reduced TG content in the serum and liver, hepatic vacuolar degeneration, and hepatic PLIN2 expression level in mice fed with a high-fat diet (HFD).

Conclusion

Yap1 LKO is protective in regulating liver and blood TG when induced with toxic substances AAI combined CCl4 and a high-fat diet.

Mitochondrial Protein-Coding Gene Expression in the Lizard Sphenomorphus incognitus (Squamata:Scincidae) Responding to Different Temperature Stresses

In the context of global warming, the frequency of severe weather occurrences, such as unexpected cold spells and heat waves, will grow, as well as the intensity of these natural disasters. Lizards, as a large group of reptiles, are ectothermic. Their body temperatures are predominantly regulated by their environment and temperature variations directly impact their behavior and physiological activities. Frequent cold periods and heat waves can affect their biochemistry and physiology, and often their ability to maintain their body temperature. Mitochondria, as the center of energy metabolism, are crucial for maintaining body temperature, regulating metabolic rate, and preventing cellular oxidative damage. Here, we used RT-qPCR technology to investigate the expression patterns and their differences for the 13 mitochondrial PCGs in Sphenomorphus incognitus (Squamata:Scincidae), also known as the brown forest skink, under extreme temperature stress at 4 °C, 8 °C, 34 °C, and 38 °C for 24 h, compared to the control group at 25 °C. In southern China, for lizards, 4 °C is close to lethal, and 8 °C induces hibernation, while 34/38 °C is considered hot and environmentally realistic. Results showed that at a low temperature of 4 °C for 24 h, transcript levels of ATP8, ND1, ND4, COI, and ND4L significantly decreased, to values of 0.52 ± 0.08, 0.65 ± 0.04, 0.68 ± 0.10, 0.28 ± 0.02, and 0.35 ± 0.02, respectively, compared with controls. By contrast, transcript levels of COIII exhibited a significant increase, with a mean value of 1.86 ± 0.21. However, exposure to 8 °C for 24 h did not lead to an increase in transcript levels. Indeed, transcript levels of ATP6, ATP8, ND1, ND3, and ND4 were significantly downregulated, to 0.48 ± 0.11, 0.68 ± 0.07, 0.41 ± 0.08, 0.54 ± 0.10, and 0.52 ± 0.07, respectively, as compared with controls. Exposure to a hot environment of 34 °C for 24 h led to an increase in transcript levels of COI, COII, COIII, ND3, ND5, CYTB, and ATP6, with values that were 3.3 ± 0.24, 2.0 ± 0.2, 2.70 ± 1.06, 1.57 ± 0,08, 1.47 ± 0.13, 1.39 ± 0.56, and 1.86 ± 0.12, respectively, over controls. By contrast, ND4L exhibited a significant decrease (to 0.31 ± 0.01) compared with controls. When exposed to 38 °C, the transcript levels of the 13 PCGs significantly increased, ranging from a 2.04 ± 0.23 increase in ND1 to a 6.30 ± 0.96 rise in ND6. Under two different levels of cold and heat stress, the expression patterns of mitochondrial genes in S. incognitus vary, possibly associated with different strategies employed by this species in response to low and high temperatures, allowing for rapid compensatory adjustments in mitochondrial electron transport chain proteins in response to temperature changes. Furthermore, this underscores once again the significant role of mitochondrial function in determining thermal plasticity in reptiles.

Cadmium exacerbates liver injury by remodeling ceramide metabolism: Multiomics and laboratory evidence

Cadmium (Cd) is a toxic heavy metal that primarily targets the liver. Cd exposure disrupts specific lipid metabolic pathways; however, the underlying mechanisms remain unclear. This study aimed to investigate the lipidomic characteristics of rat livers after Cd exposure as well as the potential mechanisms of Cd-induced liver injury. Our analysis of established Cd-exposed rat and cell models showed that Cd exposure resulted in liver lipid deposition and hepatocyte damage. Lipidomic detection, transcriptome sequencing, and experimental analyses revealed that Cd mainly affects the sphingolipid metabolic pathway and that the changes in ceramide metabolism are the most significant. In vitro experiments revealed that the inhibition of ceramide synthetase activity or activation of ceramide decomposing enzymes ameliorated the proapoptotic and pro-oxidative stress effects of Cd, thereby alleviating liver injury. In contrast, the exogenous addition of ceramide aggravated liver injury. In summary, Cd increased ceramide levels by remodeling ceramide synthesis and catabolism, thereby promoting hepatocyte apoptosis and oxidative stress and ultimately aggravating liver injury. Reducing ceramide levels can serve as a potential protective strategy to mitigate the liver toxicity of Cd. This study provides new evidence for understanding Cd-induced liver injury at the lipidomic level and insights into the health risks and toxicological mechanisms associated with Cd.

Histopathological effects of long-term exposure to realistic concentrations of cadmium in the hepatopancreas of Sparus aurata juveniles

In recent decades, cadmium has emerged as an environmental stressor in aquatic ecosystems due to its persistence and toxicity. It can enter water bodies from various natural and anthropogenic sources and, once introduced into aquatic systems, can accumulate in sediments and biota, leading to bioaccumulation and biomagnification in the food chain. For this reason, the effects of cadmium on aquatic life remain an area of ongoing research and concern. In this paper, a multidisciplinary approach was used to assess the effects of long-term exposure to an environmental concentration on the hepatopancreas of farmed juveniles of sea bream, Sparus aurata. After determining metal uptake, metallothionein production was assessed to gain insight into the organism's defence response. The effects were also assessed by histological and ultrastructural analyses. The results indicate that cadmium accumulates in the hepatopancreas at significant concentrations, inducing structural and functional damage. Despite the parallel increase in metallothioneins, fibrosis, alterations in carbohydrate distribution and endocrine disruption were also observed. These effects would decrease animal fitness although it did not translate into high mortality or reduced growth. This could depend on the fact that the animals were farmed, protected from the pressure deriving from having to search for food or escape from predators. Not to be underestimated is the return to humans, as this species is edible. Understanding the behaviour of cadmium in aquatic systems, its effects at different trophic levels and the potential risks to human health from the consumption of contaminated seafood would therefore be essential for informed environmental management and policy decisions.

Nobiletin ameliorates streptozotocin-cadmium-induced diabetic nephropathy via NF-κB signalling pathway in rats

This study sought to examine the anti-diabetic effect of nobiletin on streptozotocin (STZ)/cadmium (Cd)-induced diabetic nephrotoxic (DN) rats. The DN was induced using STZ (40 mg/kg b.w) intraperitoneally and Cd through drinking water for 12 weeks. The DN rats were treated with nobiletin of different concentrations (10, 20, and 40 mg/kg/BW). The STZ/Cd-induced DN leads to a significantly increased of the glucose levels, glycosylated haemoglobin, hepatic and kidney function markers, lipid peroxidation levels, and reduction of insulin levels, total haemoglobin, body weight, and antioxidant status markers. Our finding that nobiletin pathological impairment and diminished infiltration of neutrophil in kidney tubules and all biochemical enzymes were near normal levels in DN. More essentially, nobiletin strongly impedes the protein expression of renal nuclear NF-κB p65. Bax protein expression was significantly downregulated and elevated protein expression Bcl-2 was recorded in DN rats. These results show that nobiletin possesses antioxidant as well as anti-diabetic activities and thereby reduces chronic kidney diseases in rats.

How Does Mitochondrial Protein-Coding Gene Expression in Fejervarya kawamurai (Anura: Dicroglossidae) Respond to Extreme Temperatures?

Unusual climates can lead to extreme temperatures. Fejervarya kawamurai, one of the most prevalent anurans in the paddy fields of tropical and subtropical regions in Asia, is sensitive to climate change. The present study focuses primarily on a single question: how do the 13 mitochondrial protein-coding genes (PCGs) respond to extreme temperature change compared with 25 °C controls? Thirty-eight genes including an extra tRNA-Met gene were identified and sequenced from the mitochondrial genome of F. kawamurai. Evolutionary relationships were assessed within the Dicroglossidae and showed that Dicroglossinae is monophyletic and F. kawamurai is a sister group to the clade of (F. multistriata + F. limnocharis). Transcript levels of mitochondrial genes in liver were also evaluated to assess responses to 24 h exposure to low (2 °C and 4 °C) or high (40 °C) temperatures. Under 2 °C, seven genes showed significant changes in liver transcript levels, among which transcript levels of ATP8, ND1, ND2, ND3, ND4, and Cytb increased, respectively, and ND5 decreased. However, exposure to 4 °C for 24 h was very different in that the expressions of ten mitochondrial protein-coding genes, except ND1, ND3, and Cytb, were significantly downregulated. Among them, the transcript level of ND5 was most significantly downregulated, decreasing by 0.28-fold. Exposure to a hot environment at 40 °C for 24 h resulted in a marked difference in transcript responses with strong upregulation of eight genes, ranging from a 1.52-fold increase in ND4L to a 2.18-fold rise in Cytb transcript levels, although COI and ND5 were reduced to 0.56 and 0.67, respectively, compared with the controls. Overall, these results suggest that at 4 °C, F. kawamurai appears to have entered a hypometabolic state of hibernation, whereas its mitochondrial oxidative phosphorylation was affected at both 2 °C and 40 °C. The majority of mitochondrial PCGs exhibited substantial changes at all three temperatures, indicating that frogs such as F. kawamurai that inhabit tropical or subtropical regions are susceptible to ambient temperature changes and can quickly employ compensating adjustments to proteins involved in the mitochondrial electron transport chain.

Cadmium influence on lipid metabolism in Sprague-Dawley rats through linoleic acid and glycerophospholipid metabolism pathways

Cadmium (Cd) is widely distributed in the environment and easy adsorbed by living organisms with adverse effects. Exposure to Cd-contaminated food may disrupt lipid metabolism and increase human health risk. To study the perturbation effect of Cd on lipid metabolism in vivo, 24 male Sprague-Dawley (SD) rats were randomly assigned four groups and treated by Cd chloride solution (0, 1.375 mg/kg, 5.5 mg/kg, 22 mg/kg) for 14 days. The characteristic indexes of serum lipid metabolism were analyzed. Afterwards, untargeted metabolomics analysis was applied to explore the adverse effects of Cd on rats by liquid chromatography coupled with mass spectrometry (LC-MS). The results revealed that Cd exposure obviously decreased the average serum of triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) and caused an imbalance of endogenous compounds in the 22 mg/kg Cd-exposed group. Compared with the control group, 30 metabolites with significant differences were identified in the serum. Our results indicated that Cd caused lipid metabolic disorders in rats by disrupting linoleic acid and glycerophospholipid metabolism pathways. Furthermore, there were three kinds of remarkable differential metabolites-9Z,12Z-octadecadienoic acid, PC(20:4(8Z,11Z,14Z,17Z)/0:0), and PC(15:0/18:2(9Z,12Z)), which enriched the two significant metabolism pathways and could be the potential biomarkers.

Spirulina (Arthrospira maxima) mitigates the toxicity induced by a mixture of metal and NSAID in Xenopus laevis

Cadmium (Cd) is often detected in the environment due to its wide use in industry; also, NSAIDs are one of the most consumed pharmaceuticals, particularly diclofenac (DCF). Several studies have reported the presence of both contaminants in water bodies at concentrations ranging from ng L-1 to μg L-1; in addition, they have shown that they can induce oxidative stress in aquatic species and disturb signal transduction, cell proliferation, and intercellular communication, which could lead to teratogenesis. Spirulina has been consumed as a dietary supplement; its antioxidant, anti-inflammatory, neuroprotective, and nutritional properties are well documented. This work aimed to evaluate if Spirulina reduces the damage induced by Cd and DCF mixture in Xenopus laevis at early life stages. FETAX assay was carried out: 20 fertilized oocytes were exposed to seven different treatments on triplicate, control, Cd (24.5 μg L-1), DCF (149 μg L-1), Cd + DCF, Cd+DCF+Spirulina (2 mg L-1), Cd+DCF+Spirulina (4 mg L-1), Cd+DCF+Spirulina (10 mg L-1), malformations, mortality, and growth were evaluated after 96 h, also lipid peroxidation, superoxide dismutase and catalase activity were determined after 192 h. Cd increased DCF mortality, Cd and DCF mixture increased the incidence of malformations as well as oxidative damage; on the other hand, the results obtained show that Spirulina can be used to reduce the damage caused by the mixture of Cd and DCF since it promotes growth, reduce mortality, malformations, and oxidative stress in X. laevis.

Benefits of Chlorella vulgaris against Cadmium Chloride-Induced Hepatic and Renal Toxicities via Restoring the Cellular Redox Homeostasis and Modulating Nrf2 and NF-KB Pathways in Male Rats

In our life scenarios, we are involuntarily exposed to many heavy metals that are well-distributed in water, food, and air and have adverse health effects on animals and humans. Cadmium (Cd) is one of the most toxic 10 chemicals reported by The World Health Organization (WHO), affecting organ structure and function. In our present study, we use one of the green microalga Chlorella vulgaris (ChV, 500 mg/kg body weight) to investigate the beneficial effects against CdCl2-induced hepato-renal toxicity (Cd, 2 mg/kg body weight for 10 days) on adult male Sprague-Dawley rats. In brief, 40 adult male rats were divided into four groups (n = 10); Control, ChV, Cd, and Cd + ChV. Cadmium alters liver and kidney architecture and disturbs the cellular signaling cascade, resulting in loss of body weight, alteration of the hematological picture, and increased ALT, AST, ALP, and urea in the blood serum. Moreover, cadmium puts hepatic and renal cells under oxidative stress due to the up-regulation of lipid peroxidation resulting in a significant increase in the IgG level as an innate immunity protection and induction of the pro-inflammatory cytokines (IL-1β and TNF-α) that causes hepatic hemorrhage, irregular hepatocytes in the liver and focal glomeruli swelling and proximal tubular degeneration in the kidney. ChV additive to CdCl2, could organize the protein translation process via NF-kB/Nrf2 pathways to prevent oxidative damage by maintaining cellular redox homeostasis and improving the survival of and tolerance of cells against oxidative damage caused by cadmium. The present study shed light on the anti-inflammatory and antioxidative properties of Chlorella vulgaris that suppress the toxicity influence of CdCl2.

Growth performance and hepatic antioxidants responses to early thermal conditioning in broiler chickens

There are little data about antioxidants' status responses to early thermal conditioning (TC) on broiler chickens. Therefore, the present study was conducted to investigate the different time ages of thermal conditioning on antioxidants responses and the growth rate of broiler chicks. A total of two hundred forty-one-day-old male broiler chicks (Cobb 500) weighed on average 51.5 ± 0.5g were randomly distributed into four equal groups (60 chicks each), and chicks of each group were ranked in five replicates. The first group reared under the ambient temperature, while the second, third and fourth groups (TC3, TC5 and TC7) were subjected to early-age thermal conditioning at 39°C for 6 h on the third, fifth and seventh day of age respectively. Broilers were fed ad-libitum, and drinking water was a free choice during the experimental period. At the end of the experimental period that lasted 5 weeks, all experimental groups were exposed to heat challenge at 36°C for 6 h. Early-age thermal conditioning did not affect growth performance. Plasma corticosterone elevation in TC5 (as a post-challenge response) was the lowest among the experimental groups. Hepatic malondialdehyde significantly increased in TC5 and TC7 groups both at the post-conditioning stage and at the end of the experimental period. Hepatic glutathione, glutathione S-transferases, catalase and superoxide dismutase significantly decreased by early-age thermal conditioning compared with non-conditioned broilers. Microscopic examination of the liver sections from broilers chickens in TC5 and TC7 groups showed all the basic features of normal liver tissue, while the control and TC3 groups showed few necrotic areas. It could be concluded that early-age thermal conditioning at 39°C for 6 h on the fifth day of age could improve the antioxidant defence system of broilers without any adverse effects on growth performance.

Sea Cucumber Saponins Derivatives Alleviate Hepatic Lipid Accumulation Effectively in Fatty Acids-Induced HepG2 Cells and Orotic Acid-Induced Rats

The sulfated echinoside A (EA) and holothurin A (HA) are two prominent saponins in sea cucumber with high hemolytic activity but also superior lipid-lowering activity. Deglycosylated derivatives EA2 and HA2 exhibit low hemolysis compared to EA and HA, but their efficacies on lipid metabolism regulation remains unknown. In this study, fatty acids-treated HepG2 cells and orotic acid-treated rats were used to investigate the lipid-lowering effects of sea cucumber saponin derivatives. Both the saponin and derivatives could effectively alleviate lipid accumulation in HepG2 model, especially EA and EA2. Moreover, though the lipid-lowering effect of EA2 was not equal with EA at the same dosage of 0.05% in diet, 0.15% dosage of EA2 significantly reduced hepatic steatosis rate, liver TC and TG contents by 76%, 41.5%, and 63.7%, respectively, compared to control and reversed liver histopathological features to normal degree according to H&E stained sections. Possible mechanisms mainly included enhancement of fatty acids β-oxidation and cholesterol catabolism through bile acids synthesis and excretion, suppression of lipogenesis and cholesterol uptake. It revealed that the efficacy of EA2 on lipid metabolism regulation was dose-dependent, and 0.15% dosage of EA2 possessed better efficacy with lower toxicity compared to 0.05% dosage of EA.

The health risk for consumers under heavy metal scenarios: Reduce bioaccumulation of Cd in estuary mud crab (Scylla paramamosain) through the antagonism of Se

Heavy metal pollution has gained increasing attention over past years, and notably, cadmium (Cd) is a non-essential heavy metal that can be toxic to human and wildlife. Furthermore, selenium (Se) is a component of the selenoproteins and influences the toxicity of Cd in different organisms, and protect organisms as a kind of heavy metal antagonist. This study exposed mud crab to 5.0 mg/L Cd for 28 days, and investigated whether different concentrations (0.1, 0.2, 0.3 mg/kg) of selenite (Na₂SeO₃) or selenomethionine (SeMet) affect the bioaccumulation of Cd, serum biochemical index, antioxidant and stress-response genes of S. paramamosain. The results showed that the Cd concentration in Cd group was significantly higher than the organic or inorganic Se group. Serum biochemical index demonstrated that Se might relieve the damage or dysfunction of hepatopancreas caused by both Cd accumulation and toxicity. Furthermore, Se improved CAT, GPx T-AOC and SOD activity, and decreased MDA concentrations and the lipid peroxidation levels, antagonistic to Cd. Then, this study analyzed the expression of 26 stress-related genes, the results indicated that the inorganic and organic Se might reduce the damage of cell and the toxicity of heavy metals in the hepatopancreas after Cd exposure. Therefore, this study indicated that Se might alleviate Cd toxicity via the different antioxidative mechanisms, and increased the understanding of environmental toxins on estuary crustaceans.

Effects of short-term continuous and pulse cadmium exposure on gut histology and microbiota of adult male frogs (Pelophylax nigromaculatus) during pre-hibernation

Cadmium (Cd) is an environmental endocrine-disrupting pollutant which mainly occurs in pulsed manner in natural waters, while traditional toxicology experiments have less examined the effects of pulsed exposure. Here, we studied the effects of short-term (7 days) continuous and pulse exposure to 100 μg/L Cd on gut morphology and microbiota of frogs (Pelophylax nigromaculatus) during pre-hibernation. Compared to continuous exposure, Cd pulse exposure significantly increased individual mortality and decreased the villi height and the ratio of villi height to crypt depth of the gut. Cd continuous and pulse exposure both changed the community structure and relative abundance of intestinal microbiota. Compared to continuous exposure, Cd pulse exposure significantly decreased the relative abundance of beneficial bacteria (e.g., Cetobacterium and Aeromonas genus), and significantly increased the relative abundance of harmful bacteria (e.g., Parabacteroides, Odoribacter, and Acinetobacter genus). This study shows that the gut histology and microbiota of amphibians during pre-hibernation are more susceptible to Cd pulse exposure than continuous exposure.

Distinct responses from triglyceride and cholesterol metabolism in common carp (Cyprinus carpio) upon environmental cadmium exposure

Due to high persistence and bioavailability, Cadmium (Cd) is one of the most prevalent environmental contaminants, posing an elevating threat to the ecosystems. It has been evidenced that high-dose Cd elicits deleterious effects on aquatic organisms, but the potential toxicities of Cd at environmentally relevant concentrations remains underappreciated. In this study, we used common carp to investigate how environmental Cd exposure affects triglyceride (TG) and cholesterol metabolism and underlying mechanisms. The data indicated that Cd resulted in the shift of TG from the liver to blood and the movement of cholesterol in the opposite direction, ultimately giving rise to the storage of crude lipid in liver and muscle, especially hepatic cholesterol retention. Cholesterol, instead of TG, became the principal cause during the progression of hepatic lipid accumulation. Mechanistic investigations at transcriptional and translational levels further substantiated that Cd blocked hepatic biosynthesis of TG and enhanced TG efflux out of the liver and fatty acid β-oxidation, which collectively led to the compromised TG metabolism in the liver and accelerated TG export to the serum. Additionally, strengthened synthesis, retarded export and oxidation of cholesterol detailed the hepatic prominent cholesterol retention. Taken together, our results demonstrated that environmental exposure to Cd perturbed lipid metabolism through triggering distinct responses from hepatic TG and cholesterol homeostasis. These indicated that environmental factors (such as waterborne Cd) could be a potential contributor to the prevalence of non-alcoholic fatty-liver disease in aquaculture and more efforts should be devoted to the ecological risk assessment of pollutants under environmental scenarios.

Expression Plasticity of Peroxisomal Acyl-Coenzyme A Oxidase Genes Implies Their Involvement in Redox Regulation in Scallops Exposed to PST-Producing Alexandrium

Filter-feeding bivalves can accumulate paralytic shellfish toxins (PST) produced by toxic microalgae, which may induce oxidative stress and lipid peroxidation. Peroxisomal acyl-coenzyme A oxidases (ACOXs) are key enzymes functioning in maintaining redox and lipid homeostasis, but their roles in PST response in bivalves are less understood. Herein, a total of six and six ACOXs were identified in the Chlamys farreri and Patinopecten yessoensis genome, respectively, and the expansion of ACOX1s was observed. Gene expression analysis revealed an organ/tissue-specific expression pattern in both scallops, with all ACOXs being predominantly expressed in the two most toxic organs, digestive glands and kidneys. The regulation patterns of scallop ACOXs after exposure to different PST-producing algaes Alexandrium catenella (ACDH) and A. minutum (AM-1) were revealed. After ACDH exposure, more differentially expressed genes (DEGs) were identified in C. farreri digestive glands (three) and kidneys (five) than that in P. yessoensis (two), but the up-regulated DEGs showed similar expression patterns in both species. In C. farreri, three DEGs were found in both digestive glands and kidneys after AM-1 exposure, with two same CfACOX1s being acutely and chronically induced, respectively. Notably, these two CfACOX1s also showed different expression patterns in kidneys between ACDH (acute response) and AM-1 (chronic response) exposure. Moreover, inductive expression of CfACOXs after AM-1 exposure was observed in gills and mantles, and all DEGs in both tissues were up-regulated and their common DEGs exhibited both acute and chronic induction. These results indicate the involvement of scallop ACOXs in PST response, and their plasticity expression patterns between scallop species, among tissues, and between the exposure of different PST analogs.

Cadmium impairs zebrafish swim bladder development via ROS mediated inhibition of the Wnt / Hedgehog pathway

The posterior swim bladder is an important organ in teleost fishes, that primarily maintains buoyancy and motility for swimming and survival. In this study, we examined the molecular mechanisms of the toxicity of cadmium (Cd) on the early development of the swim bladder in zebrafish. Embryonic Cd exposure resulted in the non-inflation of the swim bladder when the ambient Cd concentration was greater than or equal to 0.25 mg/L. Cd disturbed surfactant lipid distribution and inhibited the formation of all three tissue layers in the swim bladder. Additionally, excessive Cd down-regulated Wnt (fzd3, nkd1, fzd7 and axin2) and Hedgehog (ihh, shh, ptc1 and ptc2) signaling pathways. Conversely, Wnt signaling activation partially neutralized Cd-induced swim bladder developmental defects. Moreover, ROS scavenger reduced Glutathione (GSH) effectively recovered Cd induced defects in swim bladder and Wnt/Hedgehog signaling. Taken together, our results first revealed that Cd caused swim bladder developmental defects via ROS-mediated inhibition of the Wnt and Hedgehog pathways. These results herein provide important data for future toxicological studies and risk assessments of Cd.

Effects of Separate and Combined Exposure of Cadmium and Lead on the Endochondral Ossification in Bufo gargarizans

Cadmium (Cd) and lead (Pb) are ubiquitous in aquatic environments and most studies have examined the potential effects of Cd or Pb alone on aquatic organisms. In the present study, chronic effects of Cd and Pb, alone and in combination, on Bufo gargarizans were investigated by exposing embryos to these contaminants throughout metamorphosis. Significant reductions in body mass and snout-to-vent length were observed in B. gargarizans at Gosner stage 42 (Gs 42) and Gs 46 exposed to a Cd/Pb mixture. Single and combined exposure with Cd and Pb induced histological alterations of the thyroid gland characterized by reduced colloid area and thickness of epithelial cells. There was a significant decrease in the maximum jump distance of froglets exposed to Cd alone and the Cd/Pb mixture, and the jumping capacity showed a positive correlation with hind limb length and tibia/fibula. Moreover, single metals and their mixture induced reduction of endochondral bone formation in B. gargarizans. Transcriptomic and real-time quantitative polymerase chain reaction results showed that genes involved in skeletal ossification (TRα, TRβ, Dio2, Dio3, MMP9, MMP13, Runx1, Runx2, and Runx3) were transcriptionally dysregulated by Cd and Pb exposure alone or in combination. Our results suggested that despite the low concentration tested, the Cd/Pb mixture induced more severe impacts on B. gargarizans. In addition, the Cd/Pb mixture might reduce chances of survival for B. gargarizans froglets by decreasing size at metamorphosis, impaired skeletal ossification, and reduction in jumping ability, which might result from dysregulation of genes involved in thyroid hormone action and endochondral ossification. The findings obtained could add a new dimension to understanding of the mechanisms underpinning skeletal ossification response to heavy metals in amphibians. Environ Toxicol Chem 2022;41:1228-1245. © 2022 SETAC.

Rutin Ameliorates Cadmium-Induced Necroptosis in the Chicken Liver via Inhibiting Oxidative Stress and MAPK/NF-κB Pathway

Cadmium (Cd) is a recognized toxic metal and exerts serious hepatotoxicity in animals and humans. Rutin (RUT) is a dietary bioflavonoid with strong antioxidant and anti-inflammatory potential. However, little is known about the alleviating effect of RUT against Cd-induced liver necroptosis. The aim of this study was to ascertain the ameliorative mechanism of RUT on necroptosis triggered by Cd in chicken liver. One hundred twenty-eight 100-day-old Isa hens were randomly divided into four groups: the control group, RUT group, Cd + RUT cotreated group, and Cd group. Cd exposure prominently elevated Cd accumulation and the activities of liver function indicators (ALT and AST). Furthermore, the histopathological results, the overexpression of genes (RIPK1, RIPK3, and MLKL) related to the necroptosis pathway, and low Caspase 8 levels in Cd-exposed chicken liver indicated that Cd intoxication induced necroptosis in chicken liver. Meanwhile, Cd administration drastically increased the levels of oxidizing stress biomarkers (ROS production, MDA content, iNOS activity, and NO generation), and obviously reduced the activities of antioxidant enzymes (SOD, GPx, and CAT) and total antioxidant capacity (T-AOC) in chicken liver. Cd treatment promoted the expression of the main members of the MAPK and NF-κB pathways (JNK, ERK, P38, NF-κB, and TNF-α) and activated heat shock proteins (HSP27, HSP40, HSP60, HSP70, and HSP90). However, RUT application remarkably alleviated these Cd-induced variations and necroptosis injury. Overall, our study demonstrated that RUT might prevent Cd-induced necroptosis in the chicken liver by inhibiting oxidative stress and MAPK/NF-κB pathway.

Effects of perchlorate and exogenous T4 exposures on development, metamorphosis and endochondral ossification in Bufo gargarizans larvae

Several endocrine-disrupting chemicals (EDCs) have been proven to interfere with the physiological function of thyroid hormone (TH), which affected growth and development. However, few studies have investigated the effects of EDCs on TH axis with consequence for skeletal development in amphibians. This study thus examined the potential role of perchlorate and T4 in growth, development and endochondral ossification during metamorphosis of Bufo gargarizans. Our studies showed that NaClO₄ treatment caused weight gain and delayed the developmental stage in B. gargarizans tadpoles, while T4 decreased body size and survival rate, accelerated metamorphic duration and increased the risk of early death. Histological sections suggested that NaClO₄ and T4 treatments caused damages to thyroid tissue, such as decreased thyroid gland size, follicle size, colloid area, the height of follicular epithelial cells and the number of follicles. In addition, the double skeletal staining and RT-qPCR showed that NaClO₄ and T4 treatments inhibited the endochondral ossification by regulating TH synthesis (TRs, Dios) and endochondral ossification-related genes (MMPs, Runxs, VEGFs and VEGFRs) expression levels, which might affect terrestrial locomotion and terrestrial life. Altogether, these thyroid injury and gene expression changes as caused by NaClO₄ and T4 may have an influence on development and endochondral ossification during the metamorphosis of amphibians.

Increased serum levels of cadmium are associated with an elevated risk of cardiovascular disease in adults

Previous studies have determined the effects of exposure to certain heavy metals on cardiovascular disease (CVD); however, the association between cadmium exposure and CVD in adults remains unclear. The relationship between serum levels of cadmium and the risk of CVD was studied by analyzing available data from 38,223 different participants of the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2016. After adjusting for all covariates, we found that higher serum cadmium concentrations were positively related to both the overall risk of CVD (odds ratio (OR): 1.45; 95% confidence interval (CI): 1.22, 1.72; p for trend <0.001) and the risks of its subtypes, including congestive heart failure, coronary heart disease, heart attack, and stroke. Elevated cadmium levels were associated with increased levels of lipids and inflammatory factors, including blood triglycerides, total cholesterol, white blood cells (WBCs), and C-reactive protein (CRP). Our study provided epidemiological evidence that cadmium may increase the risk of CVD by elevating blood lipids and inflammation.

Five Constituents Contributed to the Psoraleae Fructus-Induced Hepatotoxicity via Mitochondrial Dysfunction and Apoptosis

Backgrounds: Psoraleae Fructus (PF)-induced hepatotoxicity has been reported in clinical and animal experiments. However, the hepatotoxic constituents and mechanisms underlying PF-induced toxicity have remained unclear. Therefore, this study explored the potentially toxic PF components and revealed their relative mechanisms.

Methods: The hepatotoxicity of PF water (PFW) and ethanol (PFE) extracts was compared using Kunming mice. The different compositions between PFW and PFE, which were considered toxic compositions, were identified using the UHPLC-Q-Exactive MS method. Then, L02 and HepG2 cell lines were used to evaluate the toxicity of these compositions. Cell viability and apoptosis were determined through the Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. An automatic biochemical analyzer detected the aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). Lastly, we used high-content screening (HCS) to determine the levels of reactive oxygen species (ROS), lipid, and mitochondrial membrane potential (MMP).

Results: The ethanol extraction process aggravated the hepatotoxicity of PF, causing more severe injuries. The content of psoralen, isopsoralen, bavachin, psoralidin, bavachinin, neobavaisoflavone, and bakuchiol was higher in the PFE than PFW. Bavachin, psoralidin, bavachinin, neobavaisoflavone, and bakuchiol induced cell apoptosis and the AST, ALT, and ALP leakages. Furthermore, these five constituents increased intracellular lipid accumulation and ROS levels but decreased the MMP level.

Conclusion: The ethanol extraction process could induce severe PF hepatotoxicity. Bavachin, psoralidin, bavachinin, neobavaisoflavone, and bakuchiol are the main hepatotoxic ingredients. This mechanism could be associated with oxidative stress and mitochondrial damage-mediated apoptosis. Taken together, this study provides a basis for the clinical application of PF that formulates and improves its herbal standards.

Habitat differences affect the nuclear morphology of the erythrocytes and the hepatic melanin in Leptodactylus fuscus (Anura) in the Brazilian Cerrado savanna

The sensitivity of anuran to the effects of habitat destruction and contamination has led to a preoccupying global decline in their populations. Morphological biomarkers such as micronuclei and other erythrocyte nuclear abnormalities (ENAs), as well as the occurrence of hepatic melanin, can be used to evaluate the effects of habitat impacts. In the present study, these two parameters were combined for the in situ assessment of the effects of soybean cultivation on the grassfrog, Leptodactylus fuscus. Specimens were also collected from a protected area to provide a reference site (non-agricultural environment). The frequency of some of the nuclear abnormalities in the animals from the soybean plantation was much higher than that recorded at the reference site, in particular micronuclei, which were 3.6 times more frequent in the plantation, lobulated nuclei (3.4 times more frequent), and reniform nuclei, which were four times more common than at the reference site. The combined analysis of all the ENAs together also revealed a frequency approximately 1.4 times higher in the animals from the soybean plantation, in comparison with the protected area. Smaller areas of hepatic melanin were observed in the specimens from the soybean plantation. These results provide further evidence of the sensitivity of anurans to habitat impacts and indicate that animals found in soybean plantations are susceptible to systematic alterations of their cells.

Transcription profiling of cadmium-exposed livers reveals alteration of lipid metabolism and predisposition to hepatic steatosis

1. Cadmium (Cd) is a ubiquitous environmental toxicant that can cause liver steatosis and nonalcoholic fatty liver disease (NAFLD) on long-term exposure.2. Sixteen Sprague Dawley rats were randomly divided into two groups, and were administered normal saline and 5 mg/(kg·d) cadmium chloride by gavage. In vitro, BRL3A cells, a rat normal liver cell line, were treated with different concentrations of Cd to verify the sequencing results.3. The RNA-seq revealed 146 upregulated genes and 127 downregulated genes in the Cd intervention group. The key genes of lipid metabolism were significantly overexpressed, such as Cyp1a1 and Pla2g2d. The GO enrichment analysis showed that the 'sterol biosynthetic process' was the most obvious difference. The KEGG analysis showed that six of the top 10 differential pathways were related to lipid metabolism. The expression of the essential genes in BRL3A was consistent with the sequencing results. The protein-protein interaction (PPI) yielded that Cyp1a1 is in the central region of the differentially expressed gene network.4. The chronic Cd exposure is still an important environmental health problem with a probable tendency to cause NAFLD. It may possibly act by affecting the lipid metabolism in the liver, especially the synthesis and decomposition of unsaturated fatty acids.

Protective effects of Spirulina (Arthrospira maxima) against toxicity induced by cadmium in Xenopus laevis

Spirulina (Arthrospira maxima) has been recognized as a superfood and nutraceutical by its high nutritional value and the benefits of its consumption; it is an important source of lipids, proteins, vitamins, minerals, and antioxidants. It is known that spirulina has positive effects on the toxicity induced by pharmaceuticals and metals. Heavy metals such as cadmium, frequently used in industrial activities, are continuously detected in water bodies and can generate adverse effects on aquatic organisms even at low concentrations. This study aimed to evaluate the protective effect of spirulina (Arthrospira maxima) against the toxic effects induced by cadmium in the early life stages of Xenopus laevis. Twenty Xenopus laevis embryos were exposed to five different treatments on triplicate, control, cadmium (CdCl₂ 24.5 μg L^-1) and three spirulina mixtures Cd + S 1 (24.5 μg L^-1 CdCl₂ + 2 mg L^-1 spirulina), Cd + S 2 (24.5 μg L^-1 CdCl₂ + 2 mg L^-1 spirulina), Cd + S 3 (24.5 μg L^-1 CdCl₂ + 10 mg L^-1 spirulina); after 96 h of exposure: Malformations, mortality and length were evaluated; also, after 192 h, lipid peroxidation (LPX), superoxide dismutase (SOD) and catalase (CAT) were determined. All spirulina treatments decreased mortality from 34 to 50% and reduced malformations on incidence from 36 to 68%. Treatment Cd + S 3 decreased growth inhibition significantly. Spirulina treatment Cd + S 2 decreased lipidic peroxidation and antioxidant activity; these results suggest that spirulina (Arthrospira maxima) can decrease the mortality, frequency of malformations, the severity of malformations, growth inhibition, and oxidative damage induced by cadmium in Xenopus laevis embryos.

Puerarin attenuates cadmium-induced hepatic lipid metabolism disorder by inhibiting oxidative stress and inflammation in mice

Cadmium (Cd) is a common environmental pollutant with known toxic effects on the liver. Puerarin (PU), a natural flavonoid, has been shown to exert protective effect in numerous pathological processes. However, whether PU affords protection in Cd-induced liver damage is still equivocal. Therefore, 40 mice were treated with Cd and/or PU by gavage for 9 weeks, then the serum and liver samples were collected to verify this issue. In this study, Cd exposure triggered hepatic lipid metabolism disorders and resultant liver damage as evidenced by Oil Red O staining and total cholesterol (TC) and triglyceride (TG) levels in serum and liver, aspartate transaminase (AST) and alanine transaminase (ALT) levels in serum, and histopathology, which were significantly improved by PU. Moreover, PU also normalized the expression of Cd-disturbed lipid metabolism-related proteins to improve lipid accumulation, contributing to the alleviation of liver injury. Moreover, Cd-decreased antioxidative indices superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) as well as glutathione (GSH) in hepatic tissues were significantly attenuated by PU administration, while Cd-elevated hepatic malondialdehyde (MDA) and reactive oxygen species (ROS) levels were markedly down-regulated by PU treatment, demonstrating the antioxidant effect of PU against Cd exposure. In addition, PU supplementation increased the anti-inflammatory potential, and normalized the levels of proinflammatory cytokines during Cd exposure. In conclusion, these observations demonstrate that PU treatment decreases oxidative stress and inflammation response, which may contribute to prevent Cd-induced lipid metabolism disorder and consequent liver damage.

Inhibition of Metamorphosis, Thyroid Gland, and Skeletal Ossification Induced by Hexavalent Chromium in Bufo gargarizans Larvae

Hexavalent chromium (Cr [VI]) is one of the major detrimental heavy metal pollutants. In the present study, Bufo gargarizans were exposed to 0, 52, 104, 208, and 416 μg/L Cr (VI) from Gosner stage 2 until metamorphosis; and growth, development, and histological characteristics of the thyroid gland and skeletal ossification were examined. The results demonstrated that the survival rate of larvae exposed to Cr (VI) was not different from that measured in animals from the control group. However, high levels of Cr (VI) (104, 208, and 416 μg/L) were associated with significantly delayed growth and development. The suppression of skeletal ossification was observed at high Cr (VI) levels. Besides, histological alterations of the thyroid gland, such as follicular cell hyperplasia, colloid depletion, and peripheral colloid vacuolation, were found in 52 to 416 μg/L Cr (VI) treatments. The results of the present study highlight reductions in growth and development as well as percent metamorphosis and skeletal ossification due to histological alteration of the thyroid gland during exposure to Cr (VI) in B. gargarizans larvae. The present investigation could provide a basis for understanding the detrimental effects of Cr (VI) in amphibian larvae. Environ Toxicol Chem 2021;40:2474-2483. © 2021 SETAC.

Altered temperature affect body condition and endochondral ossification in Bufo gargarizans tadpoles

Bufo gargarizans is one kind of economic animals with higher medicinal value in China. In this study, B. gargarizans (Bufo gargarizans) tadpoles were reared at three different water temperature (15, 22 and 29 °C) from Gosner stages 28-46. We investigated the effects of temperature on growth, development, survival, metamorphic duration, size and skeletal ossification at Gosner stage 40, 42, and 46, as well as thyroid tissue reached metamorphic climax (Gs42). Besides, we examined the transcription levels of endochondral ossification-related genes in hind limb at metamorphic climax (Gs42). Our results showed that the growth and development of tadpoles conform to the temperature-size rule (TSR). While warm temperature resulted in the decrease in body size and hind limb length, and shorten larval period, cold temperature led to increase in body size and hind limb length but prolonged larval period. Histological examinations revealed that warm and cold temperatures caused damage to thyroid tissue. Also, warm and cold temperatures inhibited the degree of ossification with the double staining methodology. Additionally, the real-time PCR results suggested that warm and cold temperatures significantly up-regulated Runx2, VEGF and VEGFR mRNA levels, and down-regulated TRβ, MMP9, MMP13 and Runx3 mRNA levels. The up-regulation of Dio2 level and down-regulation of Dio3 level were observed in warm temperature. TRα mRNA level was significantly increased in warm temperature, but decreased in cold temperature. Collectively, these observations demonstrated that warm and cold temperatures affected endochondral ossification in B. gargarizans tadpoles, which might influence their capacity to terrestrial locomotion.

Aggregation of hepatic melanomacrophage centers in S. herzbergii (Pisces, Ariidae) as indicators of environmental change and well-being

ABSTRACT The melanomacrophage centers (MMCs) in the liver of fish are indicators of environmental conditions, as they are involved in xenobiotic biotransformation. The objective of this study was to evaluate the number of MMC in the liver of juveniles and adults of Sciades herzbergii from areas with different levels of contamination. The fish were caught at three points (reference - A1, potentially impacted - A2 and contaminated - A3), in São José bay (Maranhão, Brazil), in four samples. The livers were subjected to the standard histological procedure and 5μm sections were stained with hematoxylin-eosin. In livers of A2 adult individuals (260.50±161.50 MMCs / mm²) they presented a greater number of MMCs when compared to A3 adults (60.00 ± 30.10 MMCs / mm²). Juveniles showed considerable values in A1 (100.00 ± 0.00 MMCs/mm²) and A2 (95.33 ± 33.00 MMCs / mm²) compared to juveniles in A3 (49.00±0.00 MMCs/mm²). These high values are unexpected for young people. The average number of MMC correlated with the rainy season in the region. The use of hepatic MMCs as a biomarker of exposure to pollutants, in particular substances from fisheries systems, such as ammonia and nitrite, proved to be adequate to differentiate areas with different levels of impacts.

Assessment spermatogenic cell apoptosis and the transcript levels of metallothionein and p53 in Meretrix meretrix induced by cadmium

Cadmium (Cd) has been widely used in industry and can accumulate in the water, soil, and food. Meretrix meretrix is one of the marine shellfishes cultivated for economic purpose in China. The increasing Cd levels in coastal marine water could adversely affect the economic benefits of shellfish cultivation. In the present study, M. meretrix were exposed to different Cd²⁺ concentrations (0, 1.5, 3, 6, and 12 mg L^-1) for 5 d to evaluate the effects of Cd on spermatogenic cell. The Cd accumulation, survival rate and the indices of oxidative stress and apoptosis were determined in the spermatogenic cells of M. meretrix. The expression levels of p53 and metallothionein (MT) mRNA were also measured in the spermatogenic cells. Cd accumulation and the mortality rate of spermatogenic cells were found to increase in a dose-response manner with Cd²⁺ concentrations. Histopathology changes, especially the damage of membranous structure, were more severe as the Cd²⁺ levels in the testis became higher. The indexes of oxidative stress, including reactive oxygen species, malondialdehyde, protein carbonyl derivates and DNA-protein crosslinks all increased after exposure to Cd²⁺. However, the total antioxidant capacity gradually decreased with the increasing Cd²⁺ concentration. In addition, exposure to Cd²⁺ increased the apoptotic rate and caspase-3 and 9 activities but decreased the level of mitochondrial membrane potential and cytochrome C oxidase in the spermatogenic cells. MT mRNA expression increased in lower Cd²⁺ concentration treated groups whereas decreased in higher groups, while the p53 mRNA expression increased in a dose-response manner with Cd²⁺ and was positively correlated with the oxidative damage indices. These results indicated that Cd²⁺ caused oxidative stress and p53 induced apoptosis in the spermatogenic cells, and thus decreased the survival rate of sperm cells. This finding highlights that Cd can reduce the reproductive capacity of M. meretrix, thus threatening to wild shellfish populations and reducing the efficiency of shellfish farming.

Transcriptomic analysis of lead-induced hepatoxicology in female Japanese quails (Coturnix japonica): Implications of triglyceride synthesis, degradation and transport disruption

Lead (Pb) pollution poses great threats to mammals including human and it is also hazardous to bird life. In this study, RNA sequencing analysis was employed to examine the molecular responses to lead exposure in the liver of a toxicological model species Japanese quails (Coturnix japonica). Female birds were exposed to 0, 50, 500 and 1000 ppm waterborne Pb for 49 days. The results showed that hepatic microstructure was damaged under lead exposure featured by sinusoids dilation and irregularity as well as cell necrosis. Moreover, ultrastructural injury in the liver including mitochondrial swelling and vacuolization as well as nuclear deformation was induced by lead exposure. Lead exposure also caused the decrease of lipid droplets in the liver by oil red O staining. In addition, liver transcriptomic analysis revealed that molecular signaling and functional pathways were disrupted by lead exposure. Meanwhile, the expression of genes involved with hepatic glycerophospholipids metabolism of triglyceride synthesis and lipid transport of triglyceride transfer was significantly down-regulated by lead exposure. Moreover, the up-regulation of genes associated with fatty acid oxidation and the down-regulation of genes related with fatty acid synthesis were caused by lead exposure. The present study implied that lead induced liver malfunction and bird health risks through histopathological damages, molecular signaling disruption, genetic expression alteration and triglyceride metabolism disturbance.

Cadmium-induced toxicity to amphibian tadpoles might be exacerbated by alkaline not acidic pH level

Heavy metal pollution in natural water bodies generally interacting with other environmental stressors produces toxic effects on aquatic organisms. However, toxicological studies exploring interactive effects of these stressors are still limited. Here, tadpoles of the Zhenhai brown frog (Rana zhenhaiensis) were exposed to a 3 × 3 factorial combination, with three cadmium (Cd) concentrations (0, 10 and 100 μg/L) and three pH levels (5.0, 7.23 and 9.0) throughout the developmental period to assess combined toxic effects of Cd × pH on tadpole growth, development and physiology. Nearly all measured traits [including survival, metamorphosis and abnormality rate, metamorphosis time, post-metamorphic size, hepatic metal content, locomotor performance, antioxidant enzyme activity, and erythrocytic nuclear abnormality (ENA) frequency] were affected by Cd exposure, indicating notable Cd-induced toxicity to R. zhenhaiensis tadpoles. The pH level and its interaction with Cd also had significant impacts on most measured traits, such as survival rate, metamorphosis time, froglet jumping distance, hepatic Cd content, ENA frequency. Acidic (or alkaline) environment itself was toxic to tadpoles. However, high pH (but not low pH) level appeared to exacerbate Cd-induced toxicity to tadpoles. Excess free hydrogen ions under acidic environments might inhibit Cd2+ ions binding to cell surface, which reduced Cd accumulation in tissues. Under alkaline environments, other forms of Cd complexes in the aqueous phase probably contributed to promoting Cd accumulation. Our results indicated that Cd exposure could interact with different pH levels, producing diverse combined toxicities to amphibian larvae.

Novel insights into cytochrome P450 enzyme and solute carrier families in cadmium-induced liver injury of pigs

Cadmium (Cd) is a typical pollutant and carcinogen in environment. Exposure assessment of contaminants is an important component of occupational and environmental epidemiological studies. Early studies of Cd have focused on aquatic animals, chickens and rats. However, toxicological evaluation of Cd in pigs has not been reported. Therefore, twelve pigs were randomly divided into two groups (n = 6): the control group and the Cd group (Cd content: 15 ± 0.242 mg/kg feed) in this study, the experimental period was 30 d, and the toxic effects of Cd on the liver of weanling piglets were examined by antioxidant function, liver function, Cd content, histological examination and transcriptomics. The results showed that the changes of antioxidant function, liver function and Cd content were significant in the liver. Transcriptional profiling results showed that 399 differentially expressed genes (DEGs) were significantly up-regulated while 369 DEGs were remarkably down-regulated in Cd group, and which were concentrated in three ontologies: molecular function, cellular component and biological processes. Interestingly, significant changes in some genes of the cytochrome P450 enzyme (CYP450) and solute carrier (SLC) families have been observed and were consistent with qRT-PCR results. In conclusion, Cd could cause liver injury in weanling piglets and change the transcriptomic characteristics of liver. CYP450 and SLC families play an indispensable role in Cd-mediated hepatotoxicity. Importantly, changes in mRNA levels of CYP2B22, CYP7A1, CYP8B1, SLC26A8, SLC11A1, SLC27A2 and SLC22A7 induced by Cd have been reported for the first time. Our findings will provide a new insight for better assessing the mechanism of Cd toxicity to the liver.

Cadmium induced skeletal underdevelopment, liver cell apoptosis and hepatic energy metabolism disorder in Bufo gargarizans larvae by disrupting thyroid hormone signaling

Cadmium (Cd) is hazardous to human health and it is also highly detrimental to amphibian life. In this study, Bufo gargarizans larvae were exposed to environmentally relevant Cd concentrations of 5, 100 and 200 μg L^-1 from Gosner stage (Gs) 26 to Gs 42 of metamorphic climax about 6 weeks. The results showed thyroid structural injuries and thyroid signaling disruption were induced by high Cd exposure (100 and 200 μg L^-1). Moreover, tadpole skeleton including whole body, vertebrata, forelimb and hindlimb was developmentally delayed by high Cd exposure through downregulating the mRNA expressions of genes involved with skeletal ossification and growth pathway. Moreover, liver histopathological injuries were caused by high Cd exposure featured by hepatocytes malformation, nuclear degeneration and increasing melanomacrophage centers. Meanwhile, liver apoptosis rate showed on the rise in a dose-dependent way and Cd stimulated liver apoptosis by upregulating mRNA expressions of genes related to extrinsic and intrinsic apoptosis pathways. Furthermore, high Cd caused hepatic glucometabolism disorder by decreasing the genetic expressions associated with glycolysis and mitochondrial oxidative phosphorylation. In addition, liver lipid metabolism was disrupted by high Cd exposure through downregulating mRNA levels of genes related to fatty oxidation and upregulating mRNA levels of genes related to fatty acid synthesis. We suggested that Cd did great harm to tadpole health by disturbing thyroid function, skeletal growth, liver cell apoptosis signaling and hepatic energy metabolism pathway.

Distinct dietary cadmium toxic effects and defense strategies in two strains of gibel carp (Carassius gibelio) revealed by a comprehensive perspective

Previous studies demonstrated that gibel carp A strain was more susceptible to herpesvirus infection than other strains. Thus, we hypothesized that F strain might display better defense responses than the A strain against cadmium (Cd) exposure. To test our hypothesis, gibel carp A strain and F strain were exposed to three diets comprising of different concentrations of Cd for 8 weeks to compare their resistances to Cd. Comprehensive evaluations on biochemical, physiological and histological responses were conducted post-exposure. Results showed that no adverse effects and differences were observed on growth in two strains of gibel carp, compromising of the remarkable hepatoxicity-caused liver damage as shown by histological observations. Dietary Cd exposure stimulated antioxidant defense in the liver to counteract the Cd hepatoxicity, especially in the F strain. Activation of ER stress response positively stimulated the autophagy, then triggering apoptosis in fish after dietary Cd exposure. Thus, Cd-induced autophagy served as a protective strategy to alleviate hepatoxicity, but overaction of ER stress also triggered irreparable cell death via apoptosis. Cd induced dysregulation of lipid accumulation, which might be a common mechanism in response to hepatoxicity. Last but not least, the F strain showed stronger response on antioxidant, ER stress and autophagy, but apoptosis were remitted compared with the A strain, implying the F strain showed stronger response but better defense strategies to dietary Cd exposure. Our finding provides useful information for genetic breeding in aquaculture, and ultimately contribute to the safety assessment of aquatic products for human consumption.

Effects of difenoconazole on hepatotoxicity, lipid metabolism and gut microbiota in zebrafish (Danio rerio)

In current study, larvae and adult zebrafish were exposed to difenoconazole to assess its effect on hepatotoxicity, lipid metabolism and gut microbiota. Results demonstrated that difenoconazole could induce hepatotoxicity in zebrafish larvae and adult, 0.400, 1.00, 2.00 mg/L difenoconazole caused yolk retention, yolk sac edema or liver degeneration after embryos exposure for 120 h, hepatocyte vacuolization and neoplasm necrosis were observed in adult liver after 0.400 mg/L difenoconazole exposure for 21 d. RNA sequencing showed that the 41 and 567 differentially expressed genes in zebrafish larvae and liver induced by 0.400 mg/L difenoconazole, were concentrated in pathways related to protein digestion and absorption, pancreatic secretion, steroid biosynthesis, and different metabolic pathways including galactose or sugar metabolism. Difenoconazole exposure caused lipid accumulation in larval yolk sac, and the elevated triglyceride (TG), malondialdehyde (MDA) and reactive oxygen species (ROS) levels in larvae and liver, which further confirmed the lipid metabolism disorders induced by difenoconazole. The results further showed that difenoconazole increased the abundance of gut microbiota such as Firmicutes, Aeromonas, Enterobacteriaceae and Bacteroides, further suggested that gut microbiota might participate in lipid metabolism and hepatotoxicity during zebrafish development. These findings advanced the field of the difenoconazole-induced developmental toxicity in larvae and adult zebrafish, and the imbalance of gut microbiota provided the plausible mode of action for the liver damage and disordered lipid metabolism in zebrafish.

Effect of glyphosate (Roundup Active®) on liver of tadpoles of the colombian endemic frog Dendropsophus molitor (amphibia: Anura)

Glyphosate-based herbicide (GBH) using is increasing on a global scale. Few studies have investigated the sub-lethal effects of GBH in endemic amphibian species. The present work tested the GBH Roundup Active® on the tadpoles of Dendropsophus molitor. The exposure was in a range of plausible environmental concentrations (0-0.75 μg a.e./L) during a month. D. molitor is an endemic tropical frog of South America. The exposure from 325 μg a.e./L caused histological alterations in the liver. The high-resolution optical microscopy (HROM) detected sinusoidal dilatation and cytoplasmic vacuolization. The transmission electron microscopy (TEM) showed disorganization of the endoplasmic reticulum. Since the liver is essential for detoxification, these results suggest choric effects. Exposure to another GBH has caused histological alterations in liver tadpoles liver in a previous study, but, this study tested another endemic South-American frog for only 96h. The present work applied HROM to observe lipid alterations since it does not use organic solvents; and TEM for the ultrastructural observation of hepatocytes. Environmental risk of GBH can improve by including sub-lethal effects in endemic species.

The effects of chronic cadmium exposure on Bufo gargarizans larvae: Histopathological impairment, gene expression alteration and fatty acid metabolism disorder in the liver

Cadmium (Cd) a highly toxic metal to human and wildlife health and it is hazardous to both terrestrial and aquatic life. In this study, we used RNA sequencing analysis to examine the effects of chronic cadmium exposure on liver lipid metabolism of Bufo gargarizans larvae. Tadpoles were exposed to cadmium concentrations at 0, 5, 10, 50, 100 and 200 μg L^-1 from Gosner stage 26-42 of metamorphic climax. The results showed high dose cadmium (50, 100 and 200 μg L^-1) caused obvious histological changes characterized by hepatocytes deformation, nuclear pyknosis, increasing melanomacrophage centers (MMCs) and aggregated lipid droplets. Moreover, transcriptome analysis showed that liver function was seriously affected by cadmium exposure. Furthermore, high dose cadmium significantly upregulated the mRNA expression of elongation of very-long-chain fatty acids 1 (ELOVL1), Mitochondrial trans-2-enoyl-CoA reductase (MECR), Trans-2, 3-enoyl-CoA reductase (TER) and Hydroxysteroid (17β) dehydrogenase type 12 (HSD17B12) which are related with fatty acid synthesis. Meanwhile, mRNA levels of genes related with fat acid oxidation such as acetyl-CoA acyltransferase 2 (ACAA2) and enoyl-coenzyme A (CoA) hydratase short chain 1 (ECHS1) were significantly upregulated while the expression of Acyl-coA thioesterase 1 (ACOT1), 3-hydroxyacyl-CoA dehydrogenase (HADH), Palmitoyl-protein thioesterase 1(PPT1) and Acetyl-CoA acyltransferase 1(ACAA1) was significantly downregulated by high dose cadmium exposure. Furthermore, the mRNA level of ATP-binding cassette subfamily B member 11 (ABCB11) related with bile secretion was significantly decreased exposed to high dose cadmium. Our results suggested cadmium can cause liver dysfunction by inducing histopathological damages, genetic expression alterations and fatty acid metabolism disorder.

Comparison of the characteristics of intestinal microbiota response in Bufo gargarizans tadpoles: Exposure to the different environmental chemicals (Cu, Cr, Cd and NO3-N)

Environmental pollutants could change the intestinal microbiota communities, while data concerning the dynamics of the intestinal microbiota in response to different environmental chemicals in amphibian are lacking. We compared the effects of Cu, Cd, Cr and NO₃-N on intestinal microbiota of B. gargarizans tadpoles by using high-throughput 16S rRNA sequencing technology. Our results revealed that responses of intestinal microbiota to three metals and NO₃-N showed different characteristics. At the phylum level, the most 100 OTUs were predominantly colonized by Proteobacteria, and meanwhile, expansion of Proteobacteria was observed in Cu 64 μg/L, Cd (100 μg/L and 200 μg/L) and NO₃-N100 mg/L treatment groups. In addition, the abundance of Bacteroidetes significantly increased in the gut administrate with Cu, Cd, Cr, NO₃-N 20 mg/L exposures, while declined abundance of Fusobacteria was observed in Cu64 μg/L Cd100 μg/L Cd200μg/L-exposed groups. At the genus level, several genera exhibited increased prevalence of abundance such as Shewanella, Azospira and Flavobacterium. The functional prediction revealed that exposures of three metals and NO₃-N increase the risks of metabolic disorders and diseases. Our research could be an important step toward an assessment of the ecological risks of different chemicals to aquatic organisms using intestinal microbiota.

Association of urinary cadmium, circulating fatty acids, and risk of gestational diabetes mellitus: A nested case-control study in China

BACKGROUND

Previous studies have observed that cadmium (Cd) exposure of pregnant women was associated with increased risk of gestational diabetes mellitus (GDM). However, the potential mechanism still remains unclear. In addition, various animal studies have suggested that Cd exposure could affect fatty acids (FAs) metabolism, but data on humans are scant.

OBJECTIVES

We conducted a nested case-control study to investigate the associations of urinary Cd concentrations with levels of circulating FAs and risk of GDM in pregnant women, and further to examine the role of FAs in mediating the relationship between Cd exposure and risk of GDM.

METHODS

A total of 305 GDM cases were matched to 305 controls on pregnant women's age (±2 years) and infant's gender from a birth cohort study conducted in Wuhan, China. Urinary Cd concentrations and levels of plasma FAs between 10 and 16 gestational weeks were measured using inductively coupled plasma mass spectrometry and gas chromatography-mass spectrometry, respectively. Conditional logistic regressions models were used to estimate the associations of Cd concentrations and levels of FAs with the risk of GDM. Multiple linear regression models were applied to estimate the associations between Cd concentrations and levels of FAs. Mediation analysis was used to assess the mediating role of FAs in the association of Cd with the risk of GDM.

RESULTS

Urinary concentrations of Cd in cases (median: 0.69 μg/L) were significantly higher than controls (median: 0.59 μg/L, P < 0.05). Cd concentrations were positively associated with the risk of GDM (P_trend = 0.003). Compared to the first tertile of Cd, the adjusted odds ratios (95% confidence intervals) of GDM risk were 2.08 (1.29, 3.36) for the second tertile and 2.09 (1.32, 3.33) for the third tertile. Cd concentrations were positively correlated with levels of eicosadienoic acid and arachidonic acid/eicosapentaenoic acid ratio, but negatively correlated with levels of stearic acid, eicosapentaenoic acid, total odd-chain saturated fatty acids, total n-3 polyunsaturated fatty acids (PUFAs), and n-3 PUFAs/n-6 PUFAs ratio. We did not observe evidence that the association of Cd exposure and risk of GDM was mediated through FAs.

CONCLUSIONS

Our findings confirmed the association of higher Cd exposure with increased risk of GDM in pregnant women, and provided forceful epidemiological evidence for the relation of Cd concentrations and levels of FAs.