Molecular Mechanisms of Selenium Mitigating Lead Toxicity in Chickens via Mitochondrial Pathway: Selenoproteins, Oxidative Stress, HSPs, and Apoptosis

The influence of HSP inducers on salinity stress in sterlet sturgeon (Acipenser ruthenus): In vitro study on HSP expression, immune responses, and antioxidant capacity

Heat shock proteins (HSPs) play a crucial role in antioxidant systems, immune responses, and enzyme activation during stress conditions. Salinity changes can cause stress and energy expenditure in fish, resulting in mortality, especially in fingerlings. The purpose of this study was to examine the relationship between salinity and HSPs in stressed fish by assessing the effects of various HSP inducers (HSPis), including Pro-Tex® (800 mM), amygdalin (80 mM), and a novel synthetic compound derived from pirano piranazole (80 µM), on isolated cells from Sterlet Sturgeon (Acipenser ruthenus) exposed to 13 ‰ salinity (S13). After liver, kidney, and gill cells were cultured, the HSPi compounds were treated in vitro in the presence and absence of salinity. The expression patterns of HSP27, HSP70, and HSP90 were assessed by Western blotting. Biochemical enzymes (aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase), cortisol levels, and immune parameters (component 3, immunoglobulin M, and lysozyme) were measured before and after treatment with HSPis and HSPi + S13. According to these findings, HSPis positively modulate HSP expression, immune responses, and antioxidant levels. Furthermore, they increased in vitro cell survival by maintaining cortisol levels and biochemical enzyme activities in A. ruthenus under saline conditions (P < 0.0001). In conclusion, HSPis can increase A. ruthenus resistance to salinity stress. However, the results also indicated that these compounds can reverse the adverse effects of salinity. The effectiveness of this approach depends on further research into the effects of these ecological factors on the health status of the species, especially in vivo and in combination with other stresses.

Exposure to polymetallic contaminated sites induced toxicological effects on chicken lungs: A multi-level analysis

Heavy metal pollution is an important environmental issue causing several hazards to organisms. In the present study, we investigated the uptake and accumulation of heavy metals (Pb, Cd, Cu, and Zn) in chicken lungs after six months of breeding on polymetallic-contaminated area in Jebel Ressas village. Genotoxicity in term of micronuclei frequency as well as oxidative stress in term of enzymatic activities of Catalase (CAT), Glutathion-S-Transferase (GST) and malondialdehydes accumulation (MDA) were performed. In addition, gene expression levels involved in oxidative stress genes (cat, sod and gst), metal homeostasis (mt1 and mt4) and DNA metabolism (p53, bcl2, caspase 3 and DNA ligase) were detected. Exposed chicken lungs revealed an important heavy metal accumulation of Cd and Zn co-occurring with oxidative status modulation. Transcriptomic results unveiled an upregulation of oxidative stress and homeostasis genes. On the other hand, genes involved in DNA metabolism indicated cellular functioning towards cells death and apoptosis modulation. Moreover, the histopathological examination revealed lung lesions in the chickens exposed to heavy metal contamination. Our study highlights the hazardous effects of heavy metal pollution on chicken respiratory system.

Using heat shock protein (HSP) inducers as an approach to increase the viability of sterlet (Pisces; Acipenseridae; Acipenser ruthenus) cells against environmental diazinon toxicity

Diazinon (DZN) is an organophosphate pesticide frequently used in agriculture and released into aquatic environments. In this study, sterlet sturgeon cells were exposed to DZN to investigate possible defense mechanisms via HSP induction (HSPi). Liver, kidney, and gill cells of Acipenser ruthenus were isolated and cultured and then treated with HSPi (Pro-Tex®, amygdalin, and a novel pirano-piranazole-based synthesized compound: SZ) in the presence and absence of DZN. MTT assays were used to evaluate the effects of different HSPis and their combinations with DZN. Western blotting analysis was conducted to evaluate HSP27, HSP70, and HSP90 expression patterns in each group. The highest rates of caspase-3 and caspase-8 activities were found in the DZN group, whereas HSPi treatment resulted in the lowest rates. The combination of HSPi+DZN resulted in increased HSP levels and antioxidant parameters but decreased cortisol, immune parameters, and metabolic enzymes. Many of the studied parameters (caspases, acetylcholinesterase, antioxidant, immune, and metabolic parameters) showed significant correlations with HSP expression, indicating that HSPs may be associated with markers of sterlet cell health. The results of this study demonstrate that using HSP inducers may be a powerful and reliable way to increase A. ruthenus resistance prior to exposure to DZN.

Molecular mechanism of selenium against lead-induced apoptosis in chicken brainstem relating to heat shock protein, selenoproteins, and inflammatory cytokines

Extensive application of lead (Pb) brought about environmental pollution and toxic reactions of organisms. Selenium (Se) has the effect of antagonizing Pb poisoning in humans and animals. However, it is still unclear how Pb causes brainstem toxicity. In the present study, we wanted to investigate whether Se can alleviate Pb toxicity in chicken brainstems by reducing apoptosis. One hundred and eighty chickens were randomly divided into four groups, namely the control group, the Se group, the Pb group, and the Se/Pb group. Morphological examination, ultrastructural observation, relative mRNA expressions of genes on heat shock proteins (HSPs); selenoproteins; inflammatory cytokines; and apoptosis-related factors were investigated. The results showed that Pb exposure led to tissue damage and apoptosis in chicken brainstems. Furthermore, an atypical expression of HSPs (HSP27, HSP40, HSP60, HSP70, and HSP90); selenoprotein family glutathione peroxidase (GPx) 1, GPx2, GPx3, and GPx4), thioredoxin reductases (Txnrd) (Txnrd1, Txnrd2, and Txnrd3), dio selenoprotein famliy (diodothyronine deiodinases (Dio)1, Dio2, and Dio3), as well as other selenoproteins (selenoprotein (Sel)T, SelK, SelS, SelH, SelM, SelU, SelI, SelO, Selpb, selenoprotein n1 (Sepn1), Sepp1, Sepx1, Sepw1, 15-kDa selenoprotein (Sep15), and selenophosphate synthetases 2 (SPS2)); inflammatory cytokines (Interleukin 2 (IL-2), IL-4, IL-6, IL-12β, IL-17, and Interferon-γ (IFN-γ)); and apoptosis-related genes (B-cell lymphoma-2 (Bcl-2), tumor protein 53 (p53), Bcl-2 Associated X (Bax), Cytochrome c (Cyt c), and Caspase-3) were identified. An inflammatory reaction and apoptosis were induced in chicken brainstems after exposure to Pb. Se alleviated the abnormal expression of HSPs, selenoproteins, inflammatory cytokines, and apoptosis in brainstem tissues of chickens treated with Pb. The results indicated that HSPs, selenoproteins, inflammatory, and apoptosis were involved in Se-resisted Pb poisoning. Overall, Se had resistance effect against Pb poisoning, and can be act as an antidote for Pb poisoning in animals.

Inhalation of ammonia promotes apoptosis and induces autophagy in hepatocytes via Bax/BCl-2 and m-TOR/ATG5/LC-3bII axes

Ammonia (NH3) is an irritating gas and atmospheric pollutant that endangers the health of humans and animals by stimulating respiratory tract's mucosa and causing liver damage. However, physiological role of ammonia gas in hepatotoxicity remains unclear. To investigate the hepatotoxic effects of inhaled ammonia gas, experiments were conducted using mouse model exposed to 100 ppm of ammonia gas for 21 days. The exposed mice exhibited signs of depression, emaciation, and reduced growth. This study revealed that inhalation of ammonia led to significant decrease in water (P < 0.0001) and food intake (P < 0.05), resulting in slower growth. Histopathological analysis showed that ammonia stress alters the microstructure of the liver by enlarging the gap between hepatic lobule and fibrosis. Moreover, ammonia-induced stress significantly reduces the expression of the anti-apoptotic protein BCl-2 (P < 0.001), while elevates the mRNA expression of the pro-apoptotic gene Bax (P < 0.001). Furthermore, ammonia inhalation significantly increases the protein expression of LC-3bII (P < 0.05) and the mRNA expression of autophagy-related gene 5 (ATG5) (P < 0.05) and p62 (P < 0.05) while remarkably decreases the mRNA expression of mammalian target of rapamycin (m-TOR) (P < 0.05). In conclusion, this study demonstrates that inhalation of ammonia gas causes liver damage and suggests autophagy happening via m-TOR/p62/LC-3bII and pro-apoptosis effect mediated by Bax/BCl-2 in the liver damage caused by ammonia inhalation. Our study provides a new perspective on ammonia-induced hepatotoxicity.

The SLC38A9-mTOR axis is involved in autophagy in the juvenile yellow catfish (Pelteobagrus fulvidraco) under ammonia stress

The primary objective of this study was to examine the effect of acute ammonia stress on hepatic physiological alterations in yellow catfish by performing a comprehensive analysis of the metabolome and transcriptome. The present study showed that ammonia stress led to liver metabolic disruption, functional incapacitation, and oxidative damage. Transcriptomic and metabolomic analyses revealed transcriptional and metabolic differences in the liver of yellow catfish under control and high ammonia stress conditions. After 96 h of acute exposure to ammonia, the mRNA levels of 596 liver genes were upregulated, whereas those of 603 genes were downregulated. Enrichment analysis of the differentially expressed genes identified multiple signalling pathways associated with autophagy, including the endocytosis, autophagy-animal, and mammalian target of rapamycin signalling pathways. A total of 186 upregulated and 117 downregulated metabolites, primarily associated with amino acid biosynthesis pathways, were identified. Multi-omics integration revealed the solute carrier family 38 member 9 (SLC38A9)-mammalian target of rapamycin axis as a signalling nexus for amino acid-mediated modulation of autophagy flux, and q-PCR was used to assess the expression of autophagy-related genes (LC3a and sqstm1), revealing an initial inhibition followed by the restoration of autophagic flux during ammonia stress. Subsequent utilisation of arginine as a specific SLC38A9 activator during ammonia stress demonstrated that augmented SLC38A9 expression hindered autophagy, exacerbated ammonia toxicity, and caused a physiological decline (total cholesterol, total triglyceride, acid phosphatase, alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase levels were significantly increased), oxidative stress, and apoptosis. Autophagy activation may be an adaptive mechanism to resist ammonia stress.

Selenium and zinc supplementation mitigates metals-(loids) mixture- mediated cardiopulmonary toxicity via attenuation of antioxidant, anti-inflammatory and antiapoptotic mechanisms in female Sprague Dawley rats

This study evaluated the cardiopulmonary protective effects of essential elements (Zn and Se) against heavy metals mixture (HMM) exposure. Twenty five female Sprague Dawley albino rats, divided in to five groups: controls were orally treated only with distilled water; next, group 2 was exposed to HMM with the following concentrations: 20 mg/kg of Pb body weight, 0.40 mg/kg of Hg, 0.56 mg/kg of Mn, and 35 mg/kg of Al. Groups 3, 4 and 5 were exposed to HMM and co-treated with zinc chloride (ZnCl2; 0.80 mg/kg), sodium selenite (Na2SeO3;1.50 mg/kg) and both zinc chloride and sodium selenite, respectively. The experiment lasted for 60 days. Afterwards animals were sacrificed, and we conduced biochemical and histopathological examination of the heart and lungs. HMM only exposed animals had an increased levels of malondialdehyde (MDA) and nitric oxide (NO), increased IL-6 and TNF-α, attenuated SOD, GPx, CAT and GSH and caspase 3 in the heart and lungs. HMM affected NF-kB and Nrf2 in the heart muscle with histomorphological alterations. Zn and Se attenuated adverse effects of HMM exposure. Essential element supplementation ameliorated heavy metal cardiopulmonary intoxication in rats.

Sublethal Effects of Polystyrene Nanoplastics on the Embryonic Development of Artemia salina (Linnaeus, 1758)

Currents, wave motion, solar radiation, and abrasion are mechanisms responsible for the degradation of large plastic artifacts and contribute to the dispersion of micro and nanoplastics into aquatic ecosystems, which are, currently, the most dangerous threats due to their invisibility and persistence. The present work evaluated the possible lethal and sublethal effects of amino-modified polystyrene nanoplastics (nPS-NH2) with diameters of 50 nm and 100 nm on Artemia salina (A. salina), an organism at the base of the trophic chain of the aquatic system, using a widely used model for the analysis of embryotoxicity from environmental pollutants. For this purpose, after evaluating the biodistribution of nanoplastics in the body of the tested animals, several endpoints such as anomalies, apoptosis, and ROS production were assessed. In addition, particular attention was dedicated to evaluating the correlation between toxicity and the particle size tested. The results reported that, despite the absence of a lethal impact, several sublethal effects involving gut and body size malformations, as well as the enhancement of apoptosis and oxidative stress in relation to an increase in tested concentration and a decrease in nanoparticle size.

Study on Dihydromyricetin Improving Aflatoxin Induced Liver Injury Based on Network Pharmacology and Molecular Docking

Aflatoxin B1 (AFB1) is a toxic food/feed contaminant and the liver is its main target organ, thus it poses a great danger to organisms. Dihydromyricetin (DHM), a natural flavonoid compound, can be used as a food additive with high safety and has been shown to have strong hepatoprotective effects. In this experiment, PPI network and KEGG pathway analysis were constructed by network pharmacological analysis technique using software and platforms such as Swiss, String, and David and Cytoscape. We screened AFB1 and DHM cross-targets and pathways of action, followed by molecular docking based on the strength of binding affinity of genes to DHM. In addition, we exposed AFB1 (200 μg/kg) to mice to establish a liver injury model. Histological observation, biochemical assay, oxidative stress indicator assay, TUNEL staining and Western blot were used to evaluate the liver injury. Network pharmacological results were screened to obtain 25 cross-targets of action and 20 pathways of action. It was found that DHM may exert anti-hepatic injury effects by inhibiting the overexpression of Caspase-3 protein and increasing the expression of Bcl-2 protein. DHM (200 mg/kg) was found to reduce AFB1-induced liver indices such as alanine aminotransferase (ALT) and aspartate acyltransferase (AST), and attenuate hepatic histopathological damage through animal models. Importantly, DHM inhibited malondialdehyde (MDA) formation in liver tissue and attenuated AFB1-induced oxidative stress injury by increasing glutathione-S-transferase (GST) glutathione (GPX) catalase (CAT) and superoxide dismutase (SOD). Meanwhile, DHM also restored the expression of anti-apoptotic protein Bcl-2 and antioxidant proteins, Nrf2, Keap1 and its downstream HO-1, and down-regulated the expression of pro-apoptotic proteins Bax and Caspase-3 in AFB1-induced liver tissues. The results confirmed that liver injury caused by AFB1 exposure could be alleviated by DHM, providing valuable guidance for in-depth study of DHM in the treatment of liver-related diseases, and laying the foundation for in-depth development and utilization of DHM.