Pluronic F127-liposome-encapsulated curcumin activates Nrf2/Keap1 signaling pathway to promote cell migration of HaCaT cells.

Curcumin (CUR) is an extract of Curcuma longa Linn., which has various pharmacological activities. The instability, low water solubility and bioavailability of CUR greatly limit its clinical application. This work prepared Pluronic F127-liposome-encapsulated curcumin (CUR-LIP-F127) and explored its functional role in wound healing. Liposome-encapsulated curcumin (CUR-LIP) and CUR-LIP-F127 were prepared. Human keratinocyte cell line (HaCaT) was treated with CUR, Pluronic F127-liposome (LIP-F127) and CUR-LIP-F127, or combined with ML385 (Nrf2 inhibitor). The expression of mRNAs and proteins was detected by quantitative real-time PCR and western blotting. MTT and wound healing assays were performed to detect cell viability and migration. CUR, LIP-F127 and CUR-LIP-F127 all had no influence on cell viability of HaCaT cells. CUR-LIP-F127 treatment significantly accelerated cell migration and enhanced the expression of nuclear factor erythroid-related factor 2 (Nrf2) and kelch-like erythroid cell-derived protein 1 (Keap1) in HaCaT cells with respect to CUR or LIP-F127 treatment. ML385 treatment impaired CUR-LIP-F127-mediated promotion of migration and up-regulation of Nrf2 and Keap1 in HaCaT cells. This work demonstrated that CUR-LIP-F127 activated Nrf2/Keap1 signaling pathway to promote migration of HaCaT cells, suggesting that CUR-LIP-F127 may contribute to wound healing.

Impact of dietary zinc on the growth performance, histopathological analysis, antioxidant capability, and inflammatory response of largemouth bass Micropterus salmoides.

Zinc plays a crucial role in the antioxidant capacity, and inflammatory response of aquatic species, but its impact on largemouth bass Micropterus salmoides is rarely reported. Therefore, this paper aimed to investigate the effects of different levels of zinc on the growth performance, histopathology, antioxidant capacity, and inflammatory cytokines of largemouth bass Micropterus salmoides. Fish with an initial weight of 7.84 ± 0.06 g were cultured for 10 weeks. Five experimental diets were prepared with supplemented proteinate Zn (Bioplex Zn, Alltech) (0, 30, 60, 90, and 120 mg/kg), which were named the Zn-42, Zn-73, Zn-103, Zn-133, and Zn-164 groups. No evident difference was found between the dietary zinc level and the survival rate, the crude lipid content of the whole fish, or the visceral somatic index. Weight gain, condition factor, whole-body crude protein content, interleukin-10, and transforming growth factor beta gene expression were gradually enhanced with up to 102.68 mg/kg zinc and decreased at higher levels. The hepatosomatic index, feed conversion ratio, malondialdehyde level in the liver, aspartate aminotransferase, and alanine transaminase activity in the serum, gradually decreased up to 102.68 mg/kg zinc, and gradually increased beyond this. Activation of the nuclear factor erythroid-derived 2-like 2/Kelch-like ECH-associated protein 1 signaling pathway gradually up-regulated the mRNA levels and activities of glutathione peroxidase, total antioxidant capacity, catalase, and superoxide dismutase in the liver, this antioxidant ability was lower when the zinc was greater than 102.68 mg/kg. The gene expressions of nuclear factor-k-gene binding and pro-inflammation cytokines (interleukin-1ß, interleukin-15, tumor necrosis factor alpha, and interleukin-8) were up-regulated up to 102.68 mg/kg zinc and then gradually repressed. In conclusion, using broken line analysis to estimate weight gain and Zn proteinate as the zinc source, the recommended dietary zinc for largemouth bass is 66.57 mg/kg zinc.

The protective role of vitamin C on intestinal damage induced by high-dose glycinin in juvenile Rhynchocypris lagowskii Dybowski.

This study was to evaluate the mitigative effects of vitamin C (VC) on growth inhibition and intestinal damage induced by glycinin in juvenile Rhynchocypris lagowskii Dybowski. 270 healthy juvenile Rhynchocypris lagowskii Dybowski (4.65 ± 0.04 g) were randomly divided into 3 treatments, and fed with control diet, 80 g/kg glycinin diet and 80 g/kg glycinin+200 mg/kg VC diet respectively for 8 weeks. The results showed that glycinin significantly decreased the weight gain rate, specific growth rate, protein efficiency rate, feed efficiency rate and feeding rate of fish compared with the control group (P < 0.05), while VC supplementation improved the growth performance and feed utilization efficiency, and reached a level similar to the control group. Similarly, VC significantly increased the crude protein content of muscle and whole-body, and hepatopancreas and intestinal protease activities of fish fed with glycinin diet (P < 0.05). The distal intestine of fish in glycinin group showed typical damage characteristics, including breakage and atrophy of intestinal mucosal fold, and increased intestinal mucosal permeability. However, fish fed the glycinin + VC diet showed an unimpaired normal intestinal morphology. Usefully, VC supplementation could also restore impaired immune function and antioxidant capacity. VC down-regulated the mRNA levels of pro-inflammatory cytokines TNF-α and IL-1ß, and up-regulated the mRNA levels of anti-inflammatory cytokines IL-10 and TGF-ß in the distal intestine of fish fed with glycinin. Furthermore, glycinin exposure could reduce the mRNA levels of HO-1, CAT and GPx by inhibiting the activation of Nrf2-Keap1 signaling pathway, while VC supplementation reversed this phenomenon and maintained the homeostasis of antioxidant defense system. Concluded, glycinin causes growth inhibition, digestive dysfunction and intestinal damage of Rhynchocypris lagowskii Dybowski, while sufficient VC intake is beneficial for fish to resist the adverse effects of glycinin.

Protocatechuic acid reduces H2O2-induced migration and oxidative stress of fibroblast-like synoviocytes in rheumatoid arthritis by activating Nrf2-Keap1 signaling pathway.

Honeycomb (Nidus vespae) is traditional Chinese medicine and can treat rheumatoid arthritis (RA), and protocatechuic acid (PCA) is a bioactive component of honeycomb. This study aimed to investigate whether PCA could reduce the H2O2-induced migration and oxidative stress of RA fibroblast-like synoviocytes (RA-FLSs). H2O2-induced RA-FLSs were used to simulate the in vitro model of RA. The viability, apoptosis, migration, invasion, and oxidative stress of RA-FLSs were detected by Cell Counting Kit-8 (CCK-8), terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, wound healing, transwell assays, DCFDA staining, and malonaldehyde and superoxide dismutase enzyme-linked immunosorbent assay kits. The expression of migration and invasion-related proteins and Nrf2/Keap1 signaling pathway-related proteins was analyzed by western blotting. As a result, PCA suppressed the viability, migration, invasion, and oxidative and promoted apoptosis of H2O2-induced RA-FLSs by activating the Nrf2/Keap1 signaling pathway. ML-385, an Nrf2 inhibitor, could enhance the viability, migration, invasion, and oxidative and inhibited apoptosis of H2O2-induced RA-FLSs. In conclusion, PCA reduced H2O2-induced migration and oxidative stress of RA-FLSs by activating the Nrf2-Keap1 signaling pathway.

[Paeoniflorin Improves Acute Lung Injury in Sepsis by Activating Nrf2/Keap1 Signaling Pathway].

OBJECTIVE: To investigate the effect of paeoniflorin (PF) on sepsis-induced acute lung injury and its relationship with nuclear factor erythyroid 2-related factor 2 (Nrf2)/Kelch-like ECH2 associated protein 1 (Keap1) signaling pathway. METHODS: Cecal ligation and puncture (CLP) was used to induce the sepsis rat model. Rats were randomly divided into 5 groups (n=10): sham group (Sham), model group (Model), low dose PF group (L-PF group, 50 mg/kg PF), high dose PF group (H-PF group, 150 mg/kg PF) and high dose PF+Nrf2 inhibitor group (H-PF+ML385 group, 150 mg/kg PF+30 mg/kg ML385). The severity of sepsis in rats was scored according to the improved severity scale of sepsis; the pathological changes of lung tissue were observed by HE staining; the activity of superoxide dismutase (SOD) in lung tissue was determined by xanthine oxidase method; the content of malondialdehyde (MDA) in lung tissue was measured by thiobarbituric acid method; and the levels of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) in lung tissues were detected by ELISA. Western blot was used to detect the expression of Nrf2, Keap1 and HO-1 proteins in lung tissues. RESULTS: Compared with Sham group, the sepsis symptoms in Model group were more serious, severe inflammatory infiltration in lung tissue, macrophages and interstitial enlargement, and the contents of pro-inflammatory factors IL-1ß, TNF-α, IL-6 and oxidative index MDA in lung tissues were significantly increased (P<0.05), while the activity of antioxidant index SOD were significantly decreased (P<0.05). The protein and mRNA expression levels of Nrf2 and HO-1 were significantly decreased (P<0.05), while the protein and mRNA expression levels of Keap1 were markedly increased (P<0.05). Compared with the Model group, the severity of sepsis in PF groups was decreased, the lung tissue injury was improved, the contents of IL-1ß, TNF-α, IL-6 and MDA in lung tissue were significantly decreased (P<0.05), the activity of SOD was markedly increased (P<0.05), the protein and mRNA expression levels of Nrf2 and HO-1 were significantly increased (P<0.05), and the expression levels of Keap1 protein and mRNA were significantly decreased (P<0.05). Compared with the H-PF group, Nrf2 inhibitor ML385 significantly inhibited the improvement of PF on lung injury in sepsis rats. CONCLUSION: PF can reduce oxidative stress and inflammation by activating Nrf2/Keap1 signaling pathway, and improve sepsis-induced acute lung injury.

Toxic effects of environmentally relevant concentrations of naproxen exposure on Daphnia magna including antioxidant system, development, and reproduction.

Naproxen (NPX) is one of common non-prescription non-steroidal anti-inflammatory drugs (NSAIDs) which is widely detected in aquatic environments worldwide due to its high usage and low degradation. NPX exerts anti-inflammatory and analgesic pharmacological effects through the inhibition of prostaglandin-endoperoxide synthase (PTGS), also known as cyclooxygenase (COX). Given its evolutionarily relatively conserved biological functions, the potential toxic effects of NPX on non-target aquatic organisms deserve more attention. However, the ecotoxicological studies of NPX mainly focused on its acute toxic effects under higher concentrations while the chronic toxic effects under realistic concentrations exposure, especially for the underlying molecular mechanisms still remain unclear. In the present study, Daphnia magna, being widely distributed in freshwater aquatic environments, was selected to investigate the toxic effects of environmentally relevant concentrations of NPX via determining the response of the Nrf2/Keap1 signaling pathway-mediated antioxidant system in acute exposure, as well as the changes in life-history traits, such as growth, reproduction, and behavior in chronic exposure. The results showed that the short-term exposure to NPX (24 h and 48 h) suppressed ptgs2 expression while activating Nrf2/Keap1 signaling pathway and its downstream antioxidant genes (ho-1, sod, cat and trxr). However, with prolonged exposure to 96 h, the opposite performance was observed, the accumulation of malondialdehyde (MDA) indicated that D. magna suffered from severe oxidative stress. To maintain homeostasis, the exposed organism may trigger ferroptosis and apoptosis processes with the help of Silent mating type information regulation 2 homologs (SIRTs). The long-term chronic exposure to NPX (21 days) caused toxic effects on D. magna at the individual and population levels, including growth, reproduction and behavior, which may be closely related to the oxidative stress induced by the drug. The present study suggested that more attention should be paid to the ecological risk assessment of NSAIDs including NPX on aquatic non-target organisms.

The anti-inflammatory effects of itaconate and its derivatives in neurological disorders.

Almost 16 % of the global population is affected by neurological disorders, including neurodegenerative and cerebral neuroimmune diseases, triggered by acute or chronic inflammation. Neuroinflammation is recognized as a common pathogenic mechanism in a wide array of neurological conditions including Alzheimer's disease, Parkinson's disease, postoperative cognitive dysfunction, stroke, traumatic brain injury, and multiple sclerosis. Inflammatory process in the central nervous system (CNS) can lead to neuronal damage and neuronal apoptosis, consequently exacerbating these diseases. Itaconate, an immunomodulatory metabolite from the tricarboxylic acid cycle, suppresses neuroinflammation and modulates the CNS immune response. Emerging human studies suggest that itaconate levels in plasma and cerebrospinal fluid may serve as biomarkers associated with inflammatory responses in neurological disorders. Preclinical studies have shown that itaconate and its highly cell-permeable derivatives are promising candidates for preventing and treating neuroinflammation-related neurological disorders. The underlying mechanism may involve the regulation of immune cells in the CNS and neuroinflammation-related signaling pathways and molecules including Nrf2/KEAP1 signaling pathway, reactive oxygen species, and NLRP3 inflammasome. Here, we introduce the metabolism and function of itaconate and the synthesis and development of its derivatives. We summarize the potential impact and therapeutic potential of itaconate and its derivatives on brain immune cells and the associated signaling pathways and molecules, based on preclinical evidence via various neurological disorder models. We also discuss the challenges and potential solutions for clinical translation to promote further research on itaconate and its derivatives for neuroinflammation-related neurological disorders.

[Antioxidative effect of wheat-grain moxibustion on cyclophosphamide-induced liver injury in mice based on Nrf2-Keap1 signaling pathway].

OBJECTIVE: To observe the protective effect of wheat-grain moxibustion on cyclophosphamide (CTX)-induced liver injury in mice, and explore its mechanism based on the nuclear factor E2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) signaling pathway. METHODS: Twenty-four male CD-1 (ICR) mice were randomly divided into a blank group, a model group, and a moxibustion group, with 8 mice in each group. The mice in the model group and the moxibustion group were intraperitoneally injected with CTX (80 mg/kg) to induce liver injury. The mice in the moxibustion group were treated with wheat-grain moxibustion at "Guanyuan" (CV 4) and bilateral "Zusanli" (ST 36) and "Sanyinjiao" (SP 6), with each acupoint being treated by 3 cones, approximately 30 seconds per cone, once daily for 7 days. After intervention, the general condition of the mice was observed; the liver mass was measured and the liver index was calculated; HE staining was used to observe the morphology of the liver, and the liver tissue pathological score was assessed; ELISA was used to detect the serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH) and the levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) in the liver; Western blot and real-time fluorescence quantitative PCR were used to detect the protein and mRNA expression of Nrf2, Keap1, and quinione acceptor oxidoreductase 1 (NQO1) in the liver. RESULTS: Compared with the blank group, the mice in the model group showed sluggishness, unsteady gait, and decreased body weight; liver index was increased (P<0.01); liver cells were loosely arranged, with a small number of cell swollen and exhibiting balloon-like changes; liver tissue pathological score was increased (P<0.05); the serum levels of AST, ALT, GLDH, and level of MDA in the liver were increased (P<0.05), and the levels of SOD and GSH-Px in the liver were decreased (P<0.05); protein and mRNA expression of Nrf2 and NQO1 in the liver was decreased (P<0.01), protein and mRNA expression of Keap1 in the liver was increased (P<0.01). Compared with the model group, the mice in the moxibustion group showed improvement in general condition; liver index was decreased (P<0.01); liver cell structure was relatively intact and clear, and liver tissue pathological score was decreased (P<0.05); the serum levels of AST, ALT, GLDH, and level of MDA in the liver were decreased (P<0.05), and the levels of SOD and GSH-Px in the liver were increased (P<0.05, P<0.01); protein and mRNA expression of Nrf2 and NQO1 in the liver was increased (P<0.05), protein and mRNA expression of Keap1 in the liver was decreased (P<0.05). CONCLUSION: The wheat-grain moxibustion may alleviate CTX-induced liver injury by activating the Nrf2-Keap1 signaling pathway and enhancing the expression of antioxidative enzyme system in the body.

Enhancement of porcine in vitro embryonic development through luteolin-mediated activation of the Nrf2/Keap1 signaling pathway.

BACKGROUND: Oxidative stress, caused by an imbalance in the production and elimination of intracellular reactive oxygen species (ROS), has been recognized for its detrimental effects on mammalian embryonic development. Luteolin (Lut) has been documented for its protective effects against oxidative stress in various studies. However, its specific role in embryonic development remains unexplored. This study aims to investigate the influence of Lut on porcine embryonic development and to elucidate the underlying mechanism. RESULTS: After undergoing parthenogenetic activation (PA) or in vitro fertilization, embryos supplemented with 0.5 µmol/L Lut displayed a significant enhancement in cleavage and blastocyst formation rates, with an increase in total cell numbers and a decrease in the apoptosis rate compared to the control. Measurements on D2 and D6 revealed that embryos with Lut supplementation had lower ROS levels and higher glutathione levels compared to the control. Moreover, Lut supplementation significantly augmented mitochondrial content and membrane potential. Intriguingly, activation of the Nrf2/Keap1 signaling pathway was observed in embryos supplemented with Lut, leading to the upregulation of antioxidant-related gene transcription levels. To further validate the relationship between the Nrf2/Keap1 signaling pathway and effects of Lut in porcine embryonic development, we cultured PA embryos in a medium supplemented with brusatol, with or without the inclusion of Lut. The positive effects of Lut on developmental competence were negated by brusatol treatment. CONCLUSIONS: Our findings indicate that Lut-mediated activation of the Nrf2/Keap1 signaling pathway contributes to the enhanced production of porcine embryos with high developmental competence, and offers insight into the mechanisms regulating early embryonic development.

Ultrasonic effects on the degradation kinetics, structural characteristics and protective effects on hepatocyte lipotoxicity induced by palmitic acid of Pueraria Lobata polysaccharides.

In this study, a high-molecular-weight Pueraria lobata polysaccharide (PLP) with a molecular weight of 273.54 kDa was degraded by ultrasound, and the ultrasonic degradation kinetics, structural characteristics and hepatoprotective activity of ultrasonic degraded PLP fractions (PLPs) were evaluated. The results showed that the ultrasonic treatment significantly reduced the Mw and particle size of PLP, and the kinetic equation of ultrasonic degradation of PLP followed to the midpoint fracture model (the fist-order model). The monosaccharide composition analysis, FT-IR, triple helix structure and XRD analysis all indicated that the ultrasound degradation did not destroy the primary structure of PLP, but the thermal stability of degraded fractions improved. Additionally, the scanning electron microscopy analysis demonstrated that the surface morphology of PLP was altered from smooth, flat, compact large flaky structure to a sparse rod-like structure with sparse crosslinking (PLP-7). The degraded PLP fractions (0.5 mg/mL) with lower Mw exhibited better antioxidant activities and protective effects against palmitic acid-induced hepatic lipotoxicity, which may be due to the increased exposure of active groups such as hydroxyl groups of PLP after ultrasound. Further investigation showed that PLPs not only increased Nrf2 phosphorylation and its nuclear translocation, thereby activating Nrf2/Keap1 signaling pathway, but also enhanced HO-1, NQO-1, γ-GCL gene expressions and promoted superoxide dismutase and catalase activities, which protected hepatocytes against PA-induced oxidative stress and lipotoxicity. Overall, our research might provide an in-depth insight into P. Lobata polysaccharide in ameliorating lipid metabolic disorders, and the results revealed that ultrasonic irradiation could be a promising degradation method to produce value-added polysaccharide for use in functional food.

Mesenchymal stem cell exosomes as nanotherapeutics for dry age-related macular degeneration.

Oxidative stress-induced retinal pigment epithelial (RPE) cell damage is a major factor in the pathogenesis of dry age-related macular degeneration (AMD). Although the therapeutic effect of mesenchymal stem cell (MSC) exosomes on dry AMD has been preliminarily discussed, the underlying mechanism has yet to be reported. Here, we demonstrate that MSC exosomes, acting as a nanodrug, can effectively reduce the incidence of dry AMD by regulating Nrf2/Keap1 signaling pathway. In the in vitro study, MSC exosomes relieved the damage of ARPE-19 cells, suppressed the activity of lactate dehydrogenase (LDH), decreased the level of reactive oxygen species (ROS) and upregulated the activity of superoxide dismutase (SOD). In the in vivo study, MSC exosomes were administered via intravitreal injection. MSC exosomes effectively protected RPE layer, photoreceptor outer segment/inner segment (OS/IS) layer and outer nuclear layer (ONL) from NaIO3-induced damage. Western blotting results showed that the ratio of Bcl-2/Bax was increased after pre-administration of MSC exosomes in both in vitro and in vivo studies. Moreover, MSC exosomes were found to upregulate the expressions of Nrf2, P-Nrf2, Keap1 and HO-1, while the antioxidant effect of MSC exosomes was blocked by ML385 (a Nrf2 inhibitor). Besides, immunofluorescence results showed that MSC exosomes upregulated the expression of P-Nrf2 in the nucleus compared to the oxidant group. These results indicate that MSC exosomes protect RPE cells from oxidative damage by regulating Nrf2/Kepa1 signaling pathway. In conclusion, MSC exosomes are promising nanotherapeutics for the treatment of dry AMD.

Acetaminophen exposure alters the DNA methylation pattern of Mugilogobius chulae, along with the changes in the Nrf2-Keap1 signaling pathway.

DNA methylation can dynamically regulate multiple physiological processes in organisms in response to changes of the external environment. The effects of acetaminophen (APAP) on DNA methylation in aquatic organisms and its toxic mechanisms is an interesting issue. In the present study, Mugilogobius chulae (Approximately 225 individual), a small benthic native fish, were employed to assess the toxic effects of APAP-exposure on non-target organisms. First, under APAP exposure (0.5 µg/L and 500 µg/L) for 168 h, 17,488 and 14,458 differentially methylated regions (DMRs) were identified in liver of M. chulae, respectively, which were involved in energy metabolism, signaling transduction, and cellular processes etc. The modification of lipid metabolism by DNA methylation was particularly prominent and the increased fat vacuoles in the sections were observed. Some key nodes associated with oxidative stress and detoxification such as Kelch-1ike ECH-associated protein l (Keap1) and fumarate hydratase (FH) were modified by DNA methylation. Meanwhile, changes in DNA methyltransferase and Nrf2-Keap1 signaling pathways at different concentrations of APAP (0.5 µg/L, 5 µg/L, 50 µg/L and 500 µg/L) for different time (24 h and 168 h) were addressed at the transcriptional level. Results showed that ten eleven translocation enzymes 2 (TET2) transcript expression was upregulated 5.7-folds after being exposed to 500 µg/L APAP for 168 h, indicating the urgent need for active demethylation in the exposed organism. The elevated DNA methylation levels of Keap1 led to repression of its transcriptional expression so as to promote recovery or reactivation of Nrf2, which displayed negatively relationship with Keap1 gene. Meanwhile, P62 was significantly positively correlated with Nrf2. Downstream genes in the Nrf2 signaling pathway changed synergistically except for Trx2, in which GST and UGT were highly significantly upregulated. This work illustrated that APAP exposure altered the DNA methylation processes, together with the Nrf2-Keap1 signaling pathway, and affected the stress responses of M. chulae to pharmaceuticals exposure.

Evaluation of the biological response of propofol in zebrafish (Danio rerio): Focusing on biochemical, transcriptional, and molecular level.

Propofol, one of the most widely used intravenous anesthetic in clinical practice, has been reported to impair cognitive and memory function. However, the toxicological effects of propofol on aquatic organisms are still poorly understood. This study explored the toxic effects of chronic propofol exposure (0.008, 0.04, and 0.2 mg L-1) on adult zebrafish from biochemical, transcriptional, and molecular level after 7, 14, 21 and 28 days of exposure. Results indicated that the reactive oxygen species (ROS) levels were significantly upregulated during the 28 days exposure period, and excessive ROS caused lipid peroxidation, resulting in increased malondialdehyde (MDA) contents in the zebrafish brain. In order to relieve the oxidative damage induced by the excessive ROS, the activities of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT)) were significantly activated, and detoxification enzyme (glutathione S-transferase, GST) activities showed an "activation-inhibition" trend. However, the antioxidant enzymes and detoxification enzyme system could not eliminate the excessive ROS in time and thus caused DNA damage in zebrafish brain. The olive tail moment (OTM) values displayed a "dose-response" relationship with propofol concentrations. Meanwhile, the transcription of related genes of Nrf2-Keap1 pathway was activated. Further molecular simulation experiments suggested that propofol could directly combine with SOD/CAT to change the activity of its biological enzyme. These findings indicated that zebrafish could regulate antioxidant capacity to combat oxidative stress at the early exposure stage, but the activity of antioxidant enzymes were significantly inhibited with the increase of propofol exposure time. Our results are of great importance for understanding toxicological effects of propofol on aquatic organisms.

Translational Selenium Nanoparticles to Attenuate Allergic Dermatitis through Nrf2-Keap1-Driven Activation of Selenoproteins.

Easy recurrence and strong treatment side effects significantly limit the clinical treatment of allergic dermatitis. The human trace element selenium (Se) plays essential roles in redox regulation through incorporation into selenoproteins in the form of 21st necessary amino acid selenocysteine, to participates in the pathogenesis and intervention of chronic inflammatory diseases. Therefore, based on the safe and elemental properties of Se, we construct a facile-synthesis strategy for antiallergic selenium nanoparticles (LET-SeNPs), and scale up the production by employing a spray drying method with lactose (Lac-LET-SeNPs) or maltodextrin (Mal-LET-SeNPs) as encapsulation agents realizing larger scale production and a longer storage time. As expected, these as-prepared LET-SeNPs could effectively activate the Nrf2-Keap1 signaling pathway to enhance the expression of antioxidative selenoprotein at mRNA and protein levels, then inhibit mast cell activation to achieve efficient antiallergic activity. Interestingly, LET-SeNPs undergo metabolism to seleno-amino acids to promote biosynthesis of selenoproteins, which could suppress ROS-induced cyclooxygenase-2 (COX-2) and MAPKs activation to suppress the release of histamine and inflammatory cytokines. Allergic mouse and Macaca fascicularis models further confirm that LET-SeNPs could increase the Se content and selenoprotein expression in the skin, decrease mast cells activation and inflammatory cells infiltration, and finally exhibit the high therapeutic effects on allergic dermatitis. Taken together, this study not only constructs facile large-scale synthesis of translational Se nanomedicine to break through the bottleneck problem of nanomaterials but also sheds light on its application in the intervention and treatment of allergies.

Tolerance Assessment of Atractylodes macrocephala Polysaccharide in the Diet of Largemouth Bass (Micropterus salmoides).

Atractylodes macrocephala polysaccharide (AMP) can enhance antioxidant defense and anti-inflammation, as the tolerance levels of AMP in aquaculture is important for additive utilization. However, the tolerance dose of AMP is unknown. We assess the tolerance levels of AMP in juvenile largemouth bass (3.38 ± 0.11 g) by feeding them a 0, 400, 4000, or 8000 mg/kg AMP supplemented diet for 10 weeks. The 400 mg/kg AMP dose increased growth performance. The Nrf2/Keap1 signaling pathway was activated, as indicated by Keap1 and Nrf2 protein levels in the liver. Enhanced activity of antioxidant enzymes (SOD, GPx), together with increased mRNA levels of antioxidant genes (sod, gpx) and decreased accumulation of reactive oxygen species (ROS) and MDA, was found in the liver, implying the antioxidant effect of AMP. Nutrient absorption was enhanced by AMP, as reflected by the increased length of intestinal villi and microvilli. However, 4000 and 8000 mg/kg AMP induced oxidant stress, as indicated by increased plasma ALT and AST content and decreased mRNA levels of antioxidant genes (sod, gpx) in the liver and intestinal tissues. Inflammatory reactions were also induced by high doses of AMP, as reflected by enhanced levels of pro-inflammatory cytokines (tnfα, nfκb) in the liver, intestinal, and kidney tissues and inhibited levels of anti-inflammatory cytokines (tgfß, iκb). Histological analysis reveals inflammatory cell infiltration and tissue damage. Thus, the safe tolerance margin of AMP supplement for largemouth bass was 400-4000 mg/kg.

Dietary protein improves flesh quality by enhancing antioxidant ability via the NF-E2-related factor 2/Kelch-like ECH-associated protein 1 signaling pathway in softshell turtle (Pelodiscus sinensis).

An 8-week feeding trial was performed to assess the influence of a gradient of protein levels (14.38-45.23%) on flesh quality, skin color, amino acid profile, collagen, antioxidant capability, and antioxidant-related signaling molecule expression of the softshell turtle (Pelodiscus sinensis). Hardness, gumminess, chewiness, and yellowness values in the plastron and carapace, along with collagen, superoxide dismutase, catalase, total antioxidant capacity, and glutathione peroxidase, all improved with elevating dietary protein up to 26.19%, after which they leveled off. Additionally, total amino acids, flavor amino acids, essential amino acids, and non-essential amino acids in the muscle, as well as the expression of copper/zinc superoxide dismutase, glutathione peroxidase, catalase, manganese superoxide dismutase, NF-E2-related factor 2 were all enhanced by increasing the dietary protein level but not changed by higher protein levels. When dietary protein levels were less than 26.19%, the mRNA expression of Kelch-like ECH-associated protein 1, malondialdehyde, and redness values in the carapace and plastron were reduced, as was the lightness values of the carapace, all of which plateaued at higher protein levels. Using catalase activity and malondialdehyde as the indicators and applying a broken-line analysis, the optimal dietary protein level for P. sinensis was inferred to be 26.07 and 26.06% protein, respectively. In summary, an optimal protein input improved turtle flesh quality by strengthening antioxidant capacity in muscle tissue and by regulating the expression of antioxidant-related enzymes via the Nrf2/keap1 signaling pathway.

Vitamin C Attenuates Oxidative Stress, Inflammation, and Apoptosis Induced by Acute Hypoxia through the Nrf2/Keap1 Signaling Pathway in Gibel Carp (Carassius gibelio).

Previous studies have found that vitamin C (VC) has protective effects in fish. However, the efficacy of VC on hypoxia-induced liver injury in fish remains unknown. Therefore, to investigate the protective mechanism of VC on liver injury after acute hypoxic stimulation in fish, gibel carp were fed a diet containing VC for eight weeks, then were subjected to acute hypoxia stimulation. The specific growth rate of fish was increased by the supplementation of VC. Plasma stress markers (glucose, lactic acid, and cortisol) were decreased by the VC supplementation. Moreover, the levels of the inflammatory cytokines (tnf-α, il-2, il-6, and il-12) were increased by enhancing the Nrf2/Keap1 signaling pathway. Upregulation of the antioxidant enzymes activity (CAT, SOD, and GPx); T-AOC; and anti-inflammatory factors (il-4 and tgf-ß) highlighted the antioxidant and anti-inflammatory activities of VC. The results showed that VC reduced the apoptotic index of the fish hypothalamus. The expression of GRP78 protein in the liver and endoplasmic reticulum stress and apoptosis induced by hypoxia were inhibited by VC. Taken together, the results indicate that VC can attenuate oxidative damage, inflammation, and acute hypoxia induced apoptosis in gibel carp via the Nrf2/Keap1 signaling pathway. The results identify a new defense strategy of gibel carp in response to hypoxic conditions.

[Protective effects of Polygonatum odoratum polysaccharides on alcohol-induced injury of HepG2 cells and its mechanisms].

Objective: To investigate the protective effects of Polygonatum odoratum polysaccharides (POP) on alcohol-induced injury of HepG2 cells and its potential molecular mechanisms. Methods: After screening the appropriate concentration of alcohol-treated HepG2 cells and the intervention concentration of POP by MTT method, HepG2 cells were divided into three groups according to different intervention concentrations (200 µg/L, 400 µg/L and 600 µg/L) of POP, and the blank group without POP. After pretreated for 1 h, HepG2 cells were treated with 4% alcohol for 24 h. The activities of intracellular alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured, and the levels of intracellular reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), interleukin-1ß (IL-1ß) and tumor necrosis factor α (TNF- α) were measured. The protein expressions of Kelch-like epichlorohydrin-associated protein-1 (Keap1), phosphorylated nuclear factor E2-related factor 2 (p-Nrf2), phosphoamide adenine dinucleotide quinone oxidoreductase -1 (NQO1), B lymphocyte tumor-2 (Bcl-2), Bcl-2-associated X protein (Bax) and caspase 3 were detected. Results: Compared with the HepG2 cells treated with 4% alcohol, POP at the various concentrations could effectively down-regulate the activities of ALT and AST in HepG2 cells induced by alcohol (P＜0.05). The levels of IL-1ß and TNF-α in the 200 µg/L POP treated group were decreased significantly (P＜0.05), while the level of GSH was increased significantly (P＜0.01). The levels of ROS, MDA, IL-1ß and TNF-α in the 400 µg/L and 600 µg/L POP treated groups were decreased significantly (P＜0.05 or P＜0.01), while the GSH level was increased significantly (P＜0.01). POP effectively up-regulated the expressions of p-Nrf2 and NQO1 protein in HepG2 cells induced by alcohol, and also down-regulated the Bax/Bcl-2 index (P＜0.05), and inhibited the protein expressions of Keap1 and cleaved-caspase-3 (P＜0.05). Conclusion: POP can improve alcohol-induced oxidative stress injury in HepG2 cells by regulating the Nrf2/Keap1 pathway, thereby reducing the inflammatory index and apoptosis level of HepG2 cells. Among them, 400 µg/L and 600 µg/L POP have better intervention effects.

Oxidative stress is involved in the activation of NF-κB signal pathway and immune inflammatory response in grass carp gill induced by cypermethrin and/or sulfamethoxazole.

At present, the concentration of environmental pollutants, such as pesticides and antibiotics exposed in environment, especially in aquatic environment is increasing. Research on environmental pollutants has exploded in the last few years. However, studies on the combined effects of pesticides and antibiotics on fish are rare, especially the toxic damage to gill tissue is vague. In this paper, cypermethrin (CMN) and sulfamethoxazole (SMZ) were analyzed and found that there was a strong correlation between the pathways affected by the first 30 genes regulated by CMN and SMZ, respectively. Therefore, the toxic effects of CMN (0.651 µg L-1) and/or SMZ (0.3 µg L-1) on grass carp gill were studied in this paper. Histopathology, quantitative real-time PCR, and other methods were used to detect the tissue morphology, oxidative stress level, inflammation, and apoptosis-related indicators of the fish gills after exposure of 42 days. It was found that compared with the single exposure (CMN/SMZ) group, the combined exposure (MIX) group had a more pronounced oxidative stress index imbalance. At the same time, nuclear factor-κB (NF-κB) signal pathway was activated and immuno-inflammatory reaction appeared in MIX group. The expression of tumor necrosis factor (TNF-α) in the rising range is 2.94 times that of the C group, while the expression of interleukin 8 (IL-8) is as high as 32.67 times. This study reveals the harm of CMN and SMZ to fish, and provides a reference and basis for the rational use of pesticides and antibiotics.

Apple Polyphenols Improve Intestinal Antioxidant Capacity and Barrier Function by Activating the Nrf2/Keap1 Signaling Pathway in a Pig Model.

In recent years, the function of plant polyphenols to improve the intestinal barrier has been fully demonstrated. However, the exact mechanisms linking plant polyphenols with the intestinal barrier function have not yet been established. Apple polyphenols (APs) are safe and healthy nutrients, which are extracted from apples and their byproducts. Using pig and IPEC-J2 cell models, this study investigated the effects of dietary AP supplementation on intestinal antioxidant capacity and barrier function. Then, we further explored the role of the Nrf2/Keap1 signaling pathway in maintaining intestinal antioxidant capacity and barrier function. Our study found that dietary AP supplementation improved the intestinal mechanical barrier by promoting the intestinal morphology and intestinal tight junction protein expression, improved the intestinal immune barrier by increasing intestinal secretory immunoglobulin A production, and improved the intestinal biological barrier by increasing probiotics and decreasing the Escherichia coli population. Further research found that dietary AP supplementation increased the intestinal antioxidant capacity and activated the Nrf2/Keap1 signaling pathway. Finally, after treatment with Nrf2-specific inhibitor ML-385, the upregulation effect of APs on antioxidant capacity and tight junction protein expression was reduced in IPEC-J2 cells. Our results suggested that APs promoted intestinal antioxidant capacity and barrier function via the Nrf2/Keap1 signaling pathway.