Hemoglobin induces inflammation through NF-kB signaling pathway and causes cell oxidative damage in grass carp (Ctenopharyngodon idella)

Comparative study on the effects of saline and lactated ringer's solution as washing solutions for red blood cell transfusions

BACKGROUND AND OBJECTIVE

The objective of this research was to analyze and compare the quality, proteomics, and metabolomics of washing red blood cells (WRBCs) with saline and lactated ringer's solution (LRS) as washing solutions during storage.

METHODS

The units were divided into three bag aliquots, with one group serving as the control and not undergoing washing, another group being washed with sodium LRS, and a third group being washed with sodium chloride solution. These aliquots were stored for a period of 5 weeks, with various assays assessing the RBC storage lesion at weeks 0, 1, 3, and 5. Subsequently, the RBCs were subjected to proteomic and nontargeted metabolomic analyses at the conclusion of the storage period.

RESULTS

After testing, we found that none of the samples exceeded national standards. The concentrations of Na+ , K+ , glucose (GLU), LDH, and 2,3-DPG in washed RBCs were lower compared to unwashed RBCs during storage. Na+ and GLU levels decreased while K+ and 2,3-DPG levels increased in each group. Both the LRS and saline groups showed a decrease in the accumulation of RBC storage lesions during storage. In addition, results obtained from this integrated proteomics and metabolomics study showed changes in some proteins and metabolites. These pathways may be the core pathways of changes in the two sample groups.

CONCLUSIONS

This study indicate that the performance of RBCs washed with LRS surpasses that of those washed with Saline in certain aspects. They are safe and effective when used as washing solutions for blood transfusions.

Nrf2 protects against oxidative damage induced by hemoglobin in the liver of grass carp (Ctenopharyngodon idella)

Hemoglobin (Hb) releases during hemorrhaging and causes oxidative damage, further exacerbates the development of multiple diseases. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates cellular defenses against toxic and oxidative challenges. However, the regulation mechanism of Nrf2 in Hb-induced oxidative stress remains unclear in teleost. To accomplish this goal, a hemolysis model was established by injecting grass carp with phenylalanine (PHZ), and the immunofluorescence analysis (IFA) and hematoxylin and eosin (H&E) staining revealed that PHZ-induced hemolysis caused Hb accumulation and hepatic vacuolization, resulted in tissue damage. Prussian blue, Sirius red, and Masson staining results revealed significant iron deposition and extensive collagen fiber accumulation in the liver. IFA and immunohistochemical analyses demonstrated that PHZ-induced hemolysis markedly increased the production of reactive oxygen species (ROS), malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE). The quantitative real-time PCR (qRT-PCR) analysis data revealed that the PHZ-induced hemolysis also significantly upregulated the expression of antioxidant-related genes through activation of the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/Nrf2 signaling pathway. To further explore the molecule regulation mechanism of PHZ-induced hemolysis, the RNA-seq analysis was performed, and the data revealed that the AMPK/Nrf2 and multiple programmed cell death pathways, including ferroptosis, autophagy, apoptosis, and necroptosis in PHZ injection groups were significant upregulated. In vitro, the hemin supplementation activated the expression of target genes in the AMPK/Nrf2 pathway detected by qRT-PCR. To further verify the regulation function of Nrf2, an Nrf2 activator (4OI) was supplemented, and the flow cytometer analysis results suggested that the Hb-induced cell damage was significantly attenuated. However, the supplementary of ML385 down-regulated the AMPK/Nrf2 pathway and aggravated the hemin induced cell death. In conclusion, these findings highlight the critical regulatory role of the AMPK/Nrf2 signaling pathway in protecting against Hb-induced oxidative damage in the liver of grass carp.

Cell-free hemoglobin released from hemolysis induces programmed cell death through iron overload and oxidative stress in grass carp (Ctenopharyngodon idella)

Intravascular hemolysis releases hemoglobin (Hb) from red blood cells under specific conditions, yet the effect of hemolysis in aquaculture systems remain poorly understood. In this study, a continuous hemolysis model for grass carp was established by injection of phenylhydrazine (PHZ) to investigate the mechanistic impacts of sustained hemolysis. PHZ-induced hemolysis altered liver color, and subsequent hematoxylin and eosin staining revealed substantial Hb accumulation in the head kidney, accompanied by inflammatory cell infiltration and vacuolization in liver tissue. Quantitative real-time PCR and western blotting confirmed that PHZ treatment significantly upregulated Real-time fluorescence quantitative PCR and Western blot confirmed that PHZ treatment significantly up-regulated the expression of iron metabolism-related genes and proteins, including transferrin (Tf), ferritin, ferroportin 1 (FPN1), transferrin receptor 1 (TfR1), nuclear receptor coactivator 4 (NCOA4), divalent metal transporter 1 (DMT1), and six-transmembrane epithelial antigen of prostate 3 (STEAP3). Further investigation of PHZ-induced hemolysis effects on tissues showed that inflammation- and antioxidant enzyme-related genes in the liver and head kidney were significantly upregulated, indicating that hemolysis activated the antioxidant system and intensified inflammatory responses. Perls' staining revealed iron deposition in the head kidney and liver at ten and fourteen days post-PHZ injection. Moreover, β-galactosidase staining and transmission electron microscopy showed increased cellular senescence and mitochondrial damage, respectively, as a result of PHZ-induced hemolysis. In vitro assays with hemin treatment demonstrated increased Fe2+ content in CIK and L8824 cells, which induced oxidative stress, upregulated iron metabolism and inflammatory genes, and ultimately led to cell death. These findings suggest that excessive Hb release during sustained hemolysis leads to iron overload, elevates reactive oxygen species production, disrupts antioxidant balance, and ultimately causes cellular damage.

Hemolysis-associated release of hemoglobin induces mitochondrial oxidative phosphorylation (OXPHOS) disturbance and aggravates cell oxidative damage in grass carp (Ctenopharyngodon idella)

The liver is a key site for the removal of cell-free hemin during hemolysis. However, the mechanism underlying liver damage caused by hemolysis in teleost hemolytic disorderss remains unclear. In this study, the hemin incubation of grass carp liver cells (L8824) and phenylhydrazine (PHZ) injection were employed to simulate in vitro and in vivo hemolysis models. The Cell Counting Kit (CCK) assay results of the L8824 cells showed that the hemin caused obvious cell death and exhibited concentration-dependent characteristics. Furthermore, hemin stimulation significantly increased intracellular iron content, markedly enhanced intracellular ROS (reactive oxygen species) production, triggered the activation of genes linked to iron metabolism, and disrupted mitochondrial structural integrity. The quantitative real-time PCR (qRT-PCR) assay and enzyme activity findings indicated that the hemoglobin (Hb) treatment activated the activity and expression of mitochondrial respiratory chain complexes, while the addition of compound inhibitors I, II, and III could rescue hemin-induced cell death. Finally, a hemolysis model was established via intraperitoneal injection of PHZ in the grass carp. Histopathological analysis and in vivo transcriptome data showed that PHZ-induced hemolysis resulted in liver inflammation and iron and collagen fiber buildup. Additionally, immunofluorescence and immunohistochemical data indicated it enhanced the ROS generation, malondialdehyde (MDA), and 4-hydroxy-2-nonenal (4-HNE), destroyed the mitochondria, and up-regulated the transcription of mitochondrial respiratory chain complexes. In summary, the cell-free Hb released during hemolysis increased iron deposition, disrupted iron metabolism homeostasis, and caused oxidative stress. Consequently, this destroyed mitochondria function and ultimately exacerbated cell death.

FerrylHb induces inflammation and cell death in grass carp (Ctenopharyngodon idella) hepatocytes

Grass carp hemorrhagic disease is a significant problem in grass carp aquaculture. It releases highly oxidizing hemoglobin (Hb) into tissues, induces rapid autooxidation, and subsequently discharges cytotoxic reactive oxygen species (ROS). However, the mechanism underlying Hb damage to the teleost remains unclear. Here, we employed ferrylHb and heme to incubate L8824 (grass carp liver) cells and quantitatively analyzed the corresponding molecular regulation using the RNA-seq method. Based on the RNA-seq analysis data, after 12 h of incubation of the L8824 cells with ferrylHb, a total of 3738 differentially expressed genes (DEGs) were identified, 1824 of which were upregulated, and 1914 were downregulated. A total of 4434 DEGs were obtained in the heme treated group, with 2227 DEGs upregulated and 2207 DEGs downregulated. KEGG enrichment analysis data revealed that the incubation of ferrylHb and heme significantly activated the pathways related to Oxidative Phosphorylation, Autophagy, Mitophagy and Protein Processing in Endoplasmic Reticulum. The genes associated with NF-κB, autophagy and apoptosis pathways were selected for further validation by quantitative real-time RT-PCR (qRT-PCR). The results were consistent with the RNA-seq data. Taken together, the incubation of Hb and heme induced the molecular regulation of L8824, which consequently led to programmed cell death through multiple pathways.

Biochemical, histological and transcriptional response of intestines in Litopenaeus vannamei under chronic zinc exposure

Zinc (Zn) is an essential trace element for the normal physiological function of aquatic organisms, but it could become toxic to organisms when the concentration increased in water. As the first line of defense, the shrimp intestines are the most susceptible organ to environmental stress. In this study, the chronic toxicity of 0 (control, IC), 0.01(IL), 0.1(IM) and 1 mg/L (IH) Zn in intestines of Litopenaeus vannamei was investigated from the perspectives of biochemical, histological and transcriptional changes after exposure for 30 days. The results showed that the intestinal tissue basement membrane is swollen in the IM and IH groups and detached in the IH group. The total antioxidant capacities (T-AOC) were reduced while the content of malondialdehyde (MDA) were increased significantly in IM and IH groups. The production of reactive oxygen species (ROS) was increased significantly in IH group. Many differentially expressed genes (DEGs) were identified in IL, IM and IH groups, respectively. GO and KEGG enrichment analyses were conducted on the DEGs to obtain the underlying biological processes and pathways. The gene modules related to the sample were identified by weighted gene co-expression network analysis (WGCNA), and genes in modules highly corelated with IH group were mainly enriched in immune related pathways. Nine DEGs were selected for validation by quantitative real time PCR (qRT-PCR) and the expression profiles of these DEGs kept a well consistent with the high-throughput data, which confirmed reliability of transcriptome results. Additionally, 10 DEGs were screened to detect the changes of expression level in different groups. All these results indicated that Zn exposure could damage the intestinal barrier, provoke oxidative stress, reduce the immune function, increase the susceptibility to bacterial infections of L. vannamei and cause inflammation, ultimately result in cell apoptosis. Our study provides more perspective on the stress response of crustacean under Zn exposure.

The infection of Aeromonas hydrophila activated Multiple programmed cell death pathways in red blood cells of Clarias fuscus

In contrast to mammalian red blood cells (RBCs), Osteichthyes RBCs contain a nucleus and organelles, suggesting the involvement of more intricate mechanisms, particularly in the context of ferroptosis. In this study, we utilized RBCs from Clarias fuscus (referred to as Cf-RBCs) as a model system. We conducted RNA-seq analysis to quantify gene expression levels in Cf-RBCs after exposure to both Aeromonas hydrophila and lipopolysaccharides. Our analysis unveiled 1326 differentially expressed genes (DEGs) in Cf-RBCs following 4 h of incubation with A. hydrophila, comprising 715 and 611 genes with upregulated and downregulated expression, respectively. These DEGs were further categorized into functional clusters: 292 related to cellular processes, 241 involved in environmental information processing, 272 associated with genetic information processing, and 399 linked to organismal systems. Additionally, notable changes were observed in genes associated with the autophagy pathway at 4 h, and alterations in the ferroptosis pathway were observed at 8 h following A. hydrophila incubation. To validate these findings, we assessed the expression of cytokines (DMT1, TFR1, LC3, and GSS). All selected genes were significantly upregulated after exposure to A. hydrophila. Using flow cytometry, we evaluated the extent of ferroptosis, and the group incubated with A. hydrophila for 8 h exhibited higher levels of lipid peroxidation compared with the 4-h incubation group, even under baseline conditions. An evaluation of the glutathione redox system through GSSG/GSH ratios indicated an increased ratio in Cf-RBCs after exposure to A. hydrophila. In summary, our data suggest that A. hydrophila may induce ferroptosis in Cf-RBCs, potentially by triggering the cystine/glutamate antiporter system (system XC-), while Cf-RBCs counteract ferroptosis through the regulation of the glutathione redox system. These findings contribute to our understanding of the iron overload mechanism in Osteichthyes RBCs, provide insights into the management of bacterial diseases in Clarias fuscus, and offer potential strategies to mitigate economic losses in aquaculture.

Quercetin attenuates environmental Avermectin-induced ROS accumulation and alleviates gill damage in carp through activation of the Nrf2 pathway

Avermectin (AVM) is one of the most often used insecticides which is toxic to aquatic organisms, and cause oxidative-induced damages to the fish respiratory organ, the "gills". To better understand the mechanism by which an antioxidant reduces AVM-induced gill damage, we investigated the effects of Quercetin (Que) on AVM induction of oxidative stress to inhibit damages to the gills using common carp as a model organism. The Que is a fruit and vegetable rich flavonoid with antioxidant activity. In this study, four groups were created: the Control group, the Que group (400 mg/kg), the AVM group (2.404 μg/L), and the Que plus AVM group. The analytical methods were pathological structure examination, qPCR, Reactive Oxygen Species (ROS) and Western blot. The results showed that Que alleviated AVM-induced oxidative stress, inflammatory damage and apoptosis in the carp gills by activating the Nrf2 pathway. The mechanism was that Que alleviated the accumulation of ROS, reduced the balance between oxidation and antioxidant disrupted by AVM exposure, lowered the content of lipid peroxidation produced malondialdehyde (MDA), and increased the content of antioxidant enzymes including glutathione (GSH) and catalase (CAT). Nrf2 pathway was activated. Meanwhile, Que inhibited gill apoptosis in carp by decreasing the levels of Bax, Cytochrome C, Caspase9, Cleaved-Caspase3 and reduced Bcl2. This has important implications for future studies on Que and AVM. New suggestions are provided to reduce the threat of aquatic environmental pollution.

Ferulic acid alleviates carp brain damage and growth inhibition caused by avermectin by modulating the Nrf2/Keap1 and NF-κB signaling pathways

The increasing concern over environmental pollution caused by the pesticide avermectin used in aquaculture has attracted significant attention. The use of avermectin, a neurotoxic pesticide, in aquatic environments leads to toxic effects on non-target organisms, particularly causing harm to fish. The phenolic compound ferulic acid possesses excellent anti-inflammatory and antioxidant capabilities. This study was conducted by establishing a chronic exposure experiment to avermectin, proposes the use of ferulic acid as a dietary additive to protect the carp brain from damage caused by exposure to avermectin. Furthermore, it investigates the anti-inflammatory and antioxidant effects of ferulic acid in the carp brain under chronic exposure to avermectin. The experimental results demonstrate that ferulic acid can alleviate brain tissue inflammation and oxidative stress by modulating the Nrf2/Keap1 and NF-κB signaling pathways. It protects the carp brain from chronic avermectin-induced damage, preserves the integrity of the carp blood-brain barrier, enhances the levels of feeding factors, and thereby alleviates carp growth inhibition. These findings provide new therapeutic strategies and a theoretical foundation for the sustainable development of carp aquaculture.

Climbazole causes cell apoptosis and lipidosis in the liver of grass carp

Climbazole, an azole, is widely used in personal care products, pharmaceuticals, and pesticides and is frequently detected in surface water. Climbazole has showed endocrine-disrupting effects. However, the effects of climbazole in fish are still largely unclear. In this study, grass carp (Ctenopharyngodon idella) and liver cell lines (L8824 cells) were treated with climbazole at concentrations ranging from 0.2 to 20 μg/L for 42 days in vivo and 24 h in vitro to evaluate the effects on the liver, respectively. Pathological, biochemical, and gene transcription and expression analyses were conducted to examine the hepatotoxicity. Our results showed that climbazole significantly decreased the hepatosomatic index, caused cell apoptosis in vivo and in vitro, and finally accumulated lipids in the liver. Beside, climbazole increased ROS levels, reduced Nrf2 and Keap1 mRNA and protein levels, and further decreased transcription of Nrf2-dependent downstream antioxidant enzyme genes, causing oxidative stress. Moreover, climbazole increased transcription and protein levels of apoptosis-related genes. Finally, climbazole damaged mitochondrial function and structure, disrupted liver lipid metabolism. Overall, climbazole caused hepatotoxicity, leading to a high ecological risk for aquatic organisms.

Immunonutrition: facilitating mucosal immune response in teleost intestine with amino acids through oxidant-antioxidant balance

Comparative animal models generate fundamental scientific knowledge of immune responses. However, these studies typically are conducted in mammals because of their biochemical and physiological similarity to humans. Presently, there has been an interest in using teleost fish models to study intestinal immunology, particularly intestinal mucosa immune response. Instead of targeting the pathogen itself, a preferred approach for managing fish health is through nutrient supplementation, as it is noninvasive and less labor intensive than vaccine administrations while still modulating immune properties. Amino acids (AAs) regulate metabolic processes, oxidant-antioxidant balance, and physiological requirements to improve immune response. Thus, nutritionists can develop sustainable aquafeeds through AA supplementation to promote specific immune responses, including the intestinal mucosa immune system. We propose the use of dietary supplementation with functional AAs to improve immune response by discussing teleost fish immunology within the intestine and explore how oxidative burst is used as an immune defense mechanism. We evaluate immune components and immune responses in the intestine that use oxidant-antioxidant balance through potential selection of AAs and their metabolites to improve mucosal immune capacity and gut integrity. AAs are effective modulators of teleost gut immunity through oxidant-antioxidant balance. To incorporate nutrition as an immunoregulatory means in teleost, we must obtain more tools including genomic, proteomic, nutrition, immunology, and macrobiotic and metabonomic analyses, so that future studies can provide a more holistic understanding of the mucosal immune system in fish.

Protective effect of quercetin on avermectin induced splenic toxicity in carp: Resistance to inflammatory response and oxidative damage

Avermectin pollution is an important problem that cannot be ignored in aquatic system in recent years. It has brought great trouble to freshwater aquaculture, especially fishery aquaculture. Plant-derived quercetin has anti-inflammatory and antioxidant properties and is widely used as a dietary additive, but its protective effect on immune damage induced by avermectin in freshwater carp remains unclear. This study evaluated the role of dietary additive quercetin supplementation in chronic avermectin exposure of carp spleen. Sixty carp were divided into 4 groups (n = 15/ group), including control group, avermectin treatment group, quercetin treatment group, quercetin and avermectin co-treatment group. Carp were exposed to a 1/10 96 h LC₅₀ dose of avermectin for 30 d and fed a carp diet containing 400 mg/kg quercetin twice a day (3% body weigh/ carp). The results showed that chronic avermectin exposure caused the loose parenchymal structure of carp spleen tissue and the increase of inflammatory cells, accompanied by increased transcription levels of pro-inflammatory il-1β, il-6, tnf-α and decreased levels of anti-inflammatory factors il-10 and tgf-β1, ROS accumulation in spleen tissue. MDA content increased and T-AOC, CAT and GSH levels decreased. Quercetin down-regulates the NF-κB pathway by inhibiting the expression of iNOS and activating p38 MAPK, blocking the transcription of inflammatory factors, and alleviating the inflammation of carp spleen caused by chronic avermectin exposure. In addition, quercetin inhibits the over-activation of Nrf2/Keap-1 signaling axis, blocks ROS accumulation, and restores the spleen REDOX homeostasis. In conclusion, quercetin, as a dietary additive for carp feed, can effectively improve the immune damage caused by avermectin pollution in aquatic environment, resist spleen inflammation and oxidative stress, and provide a theoretical basis for clinical development of freshwater carp feed.