Dietary luteolin protects against HgCl2-induced renal injury via activation of Nrf2-mediated signaling in rat

Luteolin targets the AGE-RAGE signaling to mitigate inflammation and ferroptosis in chronic atrophic gastritis

Chronic atrophic gastritis (CAG) is a chronic inflammatory disease and precancerous lesion in stomach cancer. Abnormal activation cellular ferroptosis further damages gastric tissue, which is susceptible to inflammation. Luteolin has powerful anti-inflammatory and regulatory potential for cellular ferroptosis. We aimed to clarify the involvement of luteolin in inflammation and ferroptosis during CAG. Luteolin targets were searched to identify intersecting genes in the chronic atrophic gastritis disease database. The AGE-RAGE pathway is a potential target of luteolin for the treatment of chronic atrophic gastritis and a binding site between luteolin and RAGE was predicted through a computer simulation of molecular docking. We established a CAG rat model using N-methyl-N-nitro-N-nitroguanidine. The therapeutic effect of luteolin on CAG was detected using western blotting, qPCR, hematoxylin and eosin staining, lipid oxidation (MDA), and Fe2+ assays. Luteolin inhibited the AGE-RAGE signaling pathway and reduced the inflammatory response in gastric tissues. Additionally, luteolin downregulated the concentration of (MDA) and Fe2+, and CAG downregulated the expression levels of ACSL4 and NOX1 and upregulated the expression levels of FIH1 and GPX4 ferroptosis-related proteins, thus inhibiting the ferroptosis of gastric tissue cells, which had a therapeutic effect on CAG.

Resveratrol alleviates inorganic arsenic-induced ferroptosis in chicken brain via activation of the Nrf2 signaling pathway

Inorganic arsenic (iAs) is a well-recognized environmental pollutant that induces severe brain injury in humans and animals. The antioxidant, anti-inflammatory, and anti-ferroptotic effects of resveratrol (Res) were demonstrated in multiple animal experiments. In order to investigate the protective effect of Res on iAs-induced chicken brain injury, the 40 chickens (19-d-old, female) brain injury model was established by oral administration of iAs (30 mg/L NaAsO2) for 6 weeks. All chickens had free access to both food and water during the experiment. The biochemical indices, hematoxylin-eosin staining, and related protein levels of oxidative stress, inflammation and ferroptosis were then determined. Our results indicated that Res (1000 mg/kg) alleviated the iAs-induced brain injury after 6 weeks of oral administration, primarily by reducing the interleukin-1β mRNA expression and nuclear factor kappa B and malondialdehyde level, and increasing the antioxidant enzyme activity and the mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2). Taken together, our study demonstrates that Res effectively inhibits iAs-induced oxidative stress and ferroptosis by mediating the Nrf2 signaling pathway, thereby alleviating iAs-induced brain injury in chickens. This is the first time that the amelioration effects of Res on the iAs-induced brain have been investigated from multiple perspectives.

Luteolin Alleviates Cadmium-Induced Kidney Injury by Inhibiting Oxidative DNA Damage and Repairing Autophagic Flux Blockade in Chickens

Chickens are a major source of meat and eggs in human food and have significant economic value. Cadmium (Cd) is a common environmental pollutant that can contaminate feed and drinking water, leading to kidney injury in livestock and poultry, primarily by inducing the generation of free radicals. It is necessary to develop potential medicines to prevent and treat Cd-induced nephrotoxicity in poultry. Luteolin (Lut) is a natural flavonoid compound mainly extracted from peanut shells and has a variety of biological functions to defend against oxidative damage. In this study, we aimed to demonstrate whether Lut can alleviate kidney injury under Cd exposure and elucidate the underlying molecular mechanisms. Renal histopathology and cell morphology were observed. The indicators of renal function, oxidative stress, DNA damage and repair, NAD+ content, SIRT1 activity, and autophagy were analyzed. In vitro data showed that Cd exposure increased ROS levels and induced oxidative DNA damage and repair, as indicated by increased 8-OHdG content, increased γ-H2AX protein expression, and the over-activation of the DNA repair enzyme PARP-1. Cd exposure decreased NAD+ content and SIRT1 activity and increased LC3 II, ATG5, and particularly p62 protein expression. In addition, Cd-induced oxidative DNA damage resulted in PARP-1 over-activation, reduced SIRT1 activity, and autophagic flux blockade, as evidenced by reactive oxygen species scavenger NAC application. The inhibition of PARP-1 activation with the pharmacological inhibitor PJ34 restored NAD+ content and SIRT1 activity. The activation of SIRT1 with the pharmacological activator RSV reversed Cd-induced autophagic flux blockade and cell injury. In vivo data demonstrated that Cd treatment caused the microstructural disruption of renal tissues, reduced creatinine, and urea nitrogen clearance, raised MDA content, and decreased the activities or contents of antioxidants (GSH, T-SOD, CAT, and T-AOC). Cd treatment caused oxidative DNA damage and PARP-1 activation, decreased NAD+ content, decreased SIRT1 activity, and impaired autophagic flux. Notably, the dietary Lut supplement observably alleviated these alterations in chicken kidney tissues induced by Cd. In conclusion, the dietary Lut supplement alleviated Cd-induced chicken kidney injury through its potent antioxidant properties by relieving the oxidative DNA damage-activated PARP-1-mediated reduction in SIRT1 activity and repairing autophagic flux blockade.

Ameliorative impacts of sinapic acid against mercuric chloride-induced renal toxicity: role of antioxidants and inflammatory cytokines

Because of their beneficial properties, natural products, especially medicinal plants, are becoming increasingly popular worldwide and play a significant role in research. This study was aimed to evaluate the nephroprotective effect of sinapic acid against mercuric chloride-induced renal toxicity in mice. The mice were allocated to four groups named a normal group (G1), model group (G2; received HgCl2, 1 mg/kg bw), treatments groups (G3 and G4: received 50 and 100 mg/kg bw of sinapic acid together with HgCl2). Mice received HgCl2 remarkably showed alteration in all examined biochemical biomarkers (urea, creatinine, and bilirubin), and induced alteration in blood cell picture and anemia. HgCl2 intoxication decreased both systemic and renal antioxidant activity and induced over all oxidative stress as indicated by alteration in inflammation and oxidative stress associated markers. HgCl2 affected renal histology with leukocytic and inflammatory cell infiltration, fibrosis and tubular necrosis. Administration of sinapic acid (50 and 100 mg/kg bw) markedly restored the HgCl2-induced oxidative stress (serum and renal: MDA, GSH, CAT, SOD, and T-AOC), proinflammatory cytokines (serum and renal: TNF-α, IL-6, IL-1β, and PGE2) and restored the changes on biochemical markers, and hematological parameters (hemoglobin, erythrocytes, platelets, and leukocytes). Taken together, the results of the present study disclose that sinapic acid has the potential to attenuate HgCl2-induced renal toxicity and may be an ideal choice against mercury poisoning.

Mechanism of herb pair containing Astragali Radix and Spatholobi Caulis in the treatment of myelosuppression based on network pharmacology and experimental investigation

ETHNOPHARMACOLOGICAL RELEVANCE

The Astragali Radix and Spatholobi Caulis herb pair (ARSC) is one of the most commonly used herbal combinations for bone marrow suppression. According to traditional Chinese medicine, Astragali Radix strengthens the spleen and replenishes qi, while Spatholobi Caulis is a hematinic agent that promotes blood circulation and enrichment. The compatibility of the two helps the body to tonify the spleen and kidneys and compensate for visceral deficiencies. However, the multi-target mechanism of ARSC in bone marrow suppression has remained largely unknown.

AIM OF THE STUDY

The aim of this study is to explore the key targets and signaling pathways of the traditional Chinese herbal pair ARSC for the treatment of bone marrow suppression.

MATERIALS AND METHODS

The active components of ARSC and targets for myelosuppression were screened using network databases. Cytoscape 3.8.0 was used to construct compound-target, compound-disease-target and protein-protein interaction (PPI) networks. Go-function and pathway enrichment analyses were performed to explore the potential mechanism. In vivo animal experiments were conducted to verify the molecular mechanisms.

RESULTS

The 36 active compounds were identified from the ARSC, and a total of 108 genes involved in myelosuppression were screened. VEGFA, IL6, TNF, JUN, STAT3, PTGS2, CASP3 and MMP9 genes were identified as potential drug targets in the PPI network analyzed by CytoHubba. Enrichment analysis indicated that ARSC may treat myelosuppression through various biological processes, such as apoptosis, TNF-α signaling pathway via NF-κB, PI3K/AKT/mTOR signaling pathway, IL6/JAK/STAT3 signaling pathway, P53 signaling pathway and G2/M checkpoint signaling pathway. The results of the experiment showed that the aqueous extract of ARSC significantly alleviated myelosuppression, reduced the apoptosis rate of bone marrow cells, upregulated the mRNA expression levels of TNF-α, IL-6 and VEGF, and promoted NF-κB phosphorylation in myelosuppressed mice.

CONCLUSIONS

This study identified the active components and relevant mechanisms of ARSC in the treatment of myelosuppression. Our findings predicted that ARSC could treat bone marrow suppression through multiple components, multiple targets and multiple pathways. Pharmacological experiments showed that ARSC alleviated fluorouracil-induced myelosuppression by reducing the apoptosis rate of bone marrow cells and regulating the TNF-α/NF-κB signaling pathway.

Luteolin Attenuates Oxidative Stress and Colonic Hypermobility in Water Avoidance Stress Rats by Activating the Nrf2 Signaling Pathway

SCOPE

Irritable bowel syndrome (IBS) is an intestinal disorder, whose symptoms can be alleviated by certain dietary phytochemicals. This study explores the role and potential mechanisms of a natural flavonoid luteolin (LUT) in alleviating the excessive motility of colonic smooth muscles and reducing oxidative stress in IBS with diarrhea (IBS-D) rats.

METHODS AND RESULTS

LUT reduces excessive intestinal motility and lowers reactive oxygen species (ROS) levels in a water avoidance stress (WAS) rat model. Moreover, LUT increases the protein expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), activates the nuclear translocation of Nrf2, and greatly reduces the hydrogen peroxide (H2 O2 )-induced oxidative damage in intestinal epithelial cells.

CONCLUSIONS

LUT, a phyto-active component, protects against excessive intestinal motility and diarrhea by regulating the Nrf2 signaling pathway and effectively reduces oxidative stress damage in the colon.

Bioactive compounds from Actinidia arguta fruit as a new strategy to fight glioblastoma

In recent years, there has been a significant demand for natural products as a mean of disease prevention or as an alternative to conventional medications. The driving force for this change is the growing recognition of the abundant presence of valuable bioactive compounds in natural products. On recent years Actinia arguta fruit, also known as kiwiberry, has attracted a lot of attention from scientific community due to its richness in bioactive compounds, including phenolic compounds, organic acids, vitamins, carotenoids and fiber. These bioactive compounds contribute to the fruit's diverse outstanding biological activities such as antioxidant, anti-inflammatory, neuroprotective, immunomodulatory, and anti-cancer properties. Due to these properties, the fruit may have the potential to be used in the treatment/prevention of various types of cancer, including glioblastoma. Glioblastoma is the most aggressive form of brain cancer, displaying 90 % of recurrence rate within a span of 2 years. Despite the employment of an aggressive approach, the prognosis remains unfavorable, emphasizing the urgent requirement for the development of new effective treatments. The preclinical evidence suggests that kiwiberry has potential impact on glioblastoma by reducing the cancer self-renewal, modulating the signaling pathways involved in the regulation of the cell phenotype and metabolism, and influencing the consolidation of the tumor microenvironment. Even though, challenges such as the imprecise composition and concentration of bioactive compounds, and its low bioavailability after oral administration may be drawbacks to the development of kiwiberry-based treatments, being urgent to ensure the safety and efficacy of kiwiberry for the prevention and treatment of glioblastoma. This review aims to highlight the potential impact of A. arguta bioactive compounds on glioblastoma, providing novel insights into their applicability as complementary or alternative therapies.

The protective effect of Luteolin on chicken spleen lymphocytes from ammonia poisoning through mitochondria and balancing energy metabolism disorders

Ammonia poses a significant challenge in the contemporary intensive breeding industry, resulting in substantial economic losses. Despite this, there is a dearth of research investigating efficacious strategies to prevent ammonia poisoning in poultry. Consequently, the objective of this study was to investigate the molecular mechanisms through which Luteolin (Lut) safeguards mitochondria and restores equilibrium to energy metabolism disorders, thereby shielding chicken spleen lymphocytes from the detrimental effects of ammonia poisoning. Chicken spleen lymphocytes were categorized into 3 distinct groups: the control group, the ammonia group (with the addition of 1 mmol/L of ammonium chloride), and the Lut group (with the treatment of 0.5 μg/mL of Lut for 12 h followed by the addition of 1 mmol/L of ammonium chloride). These groups were then cultured for a duration of 24 h. To investigate the potential protective effect of Lut on lymphocytes exposed to ammonia, various techniques were employed, including CCK-8 analysis, ultrastructural observation, reagent kit methodology, fluorescence microscopy, and quantitative real-time PCR (qRT-PCR). The findings indicate that Lut has the potential to mitigate the morphological damage of mitochondria caused by ammonia poisoning. Additionally, it can counteract the decline in mitochondrial membrane potential, ATP content, and ATPase activities (specifically Na+/K+-ATPase, Ca2+-ATPase, Mg2+-ATPase, and Ca/Mg2+-ATPase) following exposure to ammonia in lymphocytes. Lut also has the ability to regulate the expression of genes involved in mitochondrial fusion (Opa1, Mfn1, and Mfn2) and division (Drp1 and Mff) in spleen lymphocytes after ammonia exposure. This regulation leads to a balanced energy metabolism (HK1, HK2, LDHA, LDHB, PFK, PK, SDHB, and ACO2) and provides protection against ammonia poisoning.

Network pharmacology and experimental verification of the potential mechanism of Er-Xian decoction in aplastic anemia

To investigate the potential mechanism of Er-Xian decoction (EXD) in treating aplastic anemia (AA), the active components of EXD were screened by the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), and the targets of the components were predicted by the Swiss Target Prediction database. AA targets were collected from the GeneCards, OMIM, DisGeNET, PharmGKB, DrugBank, and TTD databases, the intersection of AA targets and EXD targets was calculated, and an herb-component-target network was constructed by Cytoscape 3.7.2 software. The STRING database was used for protein‒protein interaction (PPI) analysis, and Cytoscape 3.7.2 software was used to construct a PPI network and perform topology analysis. The core targets were imported into the DAVID database for gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The molecular docking software AutoDock was used to measure the affinity between active components and key targets. Finally, we established a mouse model of AA and verified the key targets and signaling pathways of EXD by RT‒PCR, ELISA and Western blot analysis. A total of 53 active components were screened from EXD, 2516 AA-related targets were collected, and 195 common targets were obtained. An herb-component-target network and a PPI network were successfully constructed, and 36 core targets were selected from the PPI network. The main active components of EXD include luteolin, kaempferol, berberine, etc., and key targets include PIK3CA, AKT1, STAT3, etc. GO functional enrichment analysis showed that cell components, molecular functions and biological processes with significant correlations were macromolecular complexes, protein serine/threonine/tyrosine kinase activity and protein phosphorylation, respectively. KEGG pathway analysis showed that the pathways with significant correlations included the PI3K-Akt signaling pathway and JAK-STAT signaling pathway. Molecular docking results showed that the tested key targets had good affinity for the corresponding active components. In AA mice, we found that EXD significantly increased white blood cell count, red blood cell count, platelet count and hemoglobin levels, increased mRNA levels of PIK3CA, PIK3CD, AKT1, JAK2, STAT3 and MAPK1, and promoted phosphorylation of PI3K, AKT, ERK1/2 and STAT3. In summary, EXD acts on PI3K, AKT, STAT3 and other targets through berberine, luteolin, quercetin and other components to regulate the PI3K-Akt pathway, JAK-STAT pathway and other pathways, thus exerting its therapeutic effect on AA. This study explained the Chinese medicine theory of treating AA with EXD by tonifying kidney-yang and provides a scientific basis for the use of EXD in treating AA.

Nrf2-mediated therapeutic effects of dietary flavones in different diseases

Oxidative stress (OS) is a pathological status that occurs when the body's balance between oxidants and antioxidant defense systems is broken, which can promote the development of many diseases. Nrf2, a redox-sensitive transcription encoded by NFE2L2, is the master regulator of phase II antioxidant enzymes and cytoprotective genes. In this context, Nrf2/ARE signaling can be a compelling target against OS-induced diseases. Recently, natural Nrf2/ARE regulators like dietary flavones have shown therapeutic potential in various acute and chronic diseases such as diabetes, neurodegenerative diseases, ischemia-reperfusion injury, and cancer. In this review, we aim to summarize nrf2-mediated protective effects of flavones in different conditions. Firstly, we retrospected the mechanisms of how flavones regulate the Nrf2/ARE pathway and introduced the mediator role Nrf2 plays in inflammation and apoptosis. Then we review the evidence that flavones modulated Nrf2/ARE pathway to prevent diseases in experimental models. Based on these literature, we found that flavones could regulate Nrf2 expression by mechanisms below: 1) dissociating the binding between Nrf2 and Keap1 via PKC-mediated Nrf2 phosphorylation and P62-mediated Keap1 autophagic degradation; 2) regulating Nrf2 nuclear translocation by various kinases like AMPK, MAPKs, Fyn; 3) decreasing Nrf2 ubiquitination and degradation via activating sirt1 and PI3K/AKT-mediated GSK3 inhibition; and 4) epigenetic alternation of Nrf2 such as demethylation at the promoter region and histone acetylation. In conclusion, flavones targeting Nrf2 can be promising therapeutic agents for various OS-related disorders. However, there is a lack of investigations on human subjects, and new drug delivery systems to improve flavones' treatment efficiency still need to be developed.

17beta-estradiol alleviates contusion-induced skeletal muscle injury by decreasing oxidative stress via SIRT1/PGC-1α/Nrf2 pathway

PURPOSE

This study aimed to investigate the role of 17β-estradiol (E₂) in the repair of contusion-induced myoinjury in mice and to identify the underlying molecular mechanisms.

METHODS

In vivo, contusion protocol was performed for preparing mice myoinjury model, and Injection (i.p.) of 17β-estradiol (E₂) or estrogen receptor antagonist ICI 182,780, or ovariectomy (OVX), was used to alter estrogen level of animal models. In vitro, C₂C₁₂ myoblasts were treated with H₂O₂ (oxidative stress inducer), SIRT1 inhibitor EX527, or aromatase inhibitor anastrozole. Serum E₂ level was assessed by enzyme-linked immunosorbent assay (ELISA). Muscle damage repair was evaluated by H&E staining and the activities of serum creatine kinase (CK) and lactate dehydrogenase (LDH). The oxidative stress was estimated by the levels of catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA). Western blot was performed to measure the protein expressions of SIRT1, PGC-1α, Nrf2, and HO-1.

RESULTS

We observed the elevated serum E₂ levels and the upregulated oxidative stress in damaged muscle in female mice after contusion-induction. The E₂ administration in vivo alleviated contusion-induced myoinjury in OVX mice by reducing CK and LDH activities, suppressing oxidative stress, and enhancing the expression levels of SIRT1, PGC-1α, Nrf2, and HO-1. These effects were inhibited by treatment with an ERα/β antagonist. Moreover, EX527 or anastrozole treatment exacerbated H₂O₂-induced growth inhibition and oxidative stress, and expression downregulation of SIRT1, PGC-1α, Nrf2, and HO-1 in C₂C₁₂ cells in vitro.

CONCLUSION

Our results suggest that E₂ is a positive intervention factor for muscle repair followed contusion-induced myoinjury, through its effects on suppressing oxidative stress via activating the SIRT1/PGC-1α/Nrf2 pathway.

Immunopharmacological Activities of Luteolin in Chronic Diseases

Flavonoids have been shown to have anti-oxidative effects, as well as other health benefits (e.g., anti-inflammatory and anti-tumor functions). Luteolin (3', 4', 5,7-tetrahydroxyflavone) is a flavonoid found in vegetables, fruits, flowers, and herbs, including celery, broccoli, green pepper, navel oranges, dandelion, peppermint, and rosemary. Luteolin has multiple useful effects, especially in regulating inflammation-related symptoms and diseases. In this paper, we summarize the studies about the immunopharmacological activity of luteolin on anti-inflammatory, anti-cardiovascular, anti-cancerous, and anti-neurodegenerative diseases published since 2018 and available in PubMed or Google Scholar. In this review, we also introduce some additional formulations of luteolin to improve its solubility and bioavailability.

Luteolin alleviates inorganic mercury-induced liver injury in quails by resisting oxidative stress and promoting mercury ion excretion

BackgroundInorganic mercury is a well-known toxic substance that can cause oxidative stress and liver damage. Luteolin (Lut) is a kind of natural antioxidant, which is widely found in plants. Therefore, we focused on exploring the alleviative effect of Lut on liver injury induced by mercuric chloride (HgCl₂), and the potential molecular mechanism of eliminating mercury ions in quails.Methods and resultsTwenty-one-day-old male quails were randomly split into four groups: control group, Lut group, HgCl₂ group, and HgCl₂ + Lut group. The test period was 12 weeks. The results showed that Lut could significantly ameliorate oxidative stress, the release of inflammatory factors, and liver damage caused by HgCl_2, and reduce the accumulation of Hg²⁺ in quail liver. Furthermore, Lut evidently increased the levels of protein kinase C α (PKCα), nuclear factor-erythroid-2-related factor 2 (Nrf2), and its downstream proteins, and inhibited nuclear factor-kappaB (NF-κB) production in the liver of quails treated by HgCl₂.ConclusionsTo sum up, our results suggest that Lut not only reduces the levels of oxidative stress and inflammation, but also promotes the excretion of Hg²⁺ by promoting the PKCα/Nrf2 signaling pathway to alleviate HgCl₂-induced liver injury in quails.

Banana peel extract alleviate inflammation and oxidative stress via modulation of the Nrf2/Hmox-1 and NF-κB pathways in thyroid of heavy metal mixture exposed female rats

Introduction

This is an evaluation of the effects of banana peel BP extract on the heavy metals’ mixture HMM mediated oxido-inflammatory effects in the thyroid of female albino rats.

Methods

Five groups (5 female rats/group) were treated as follows for 60 days: Group 1: Deionized water only; Group 2: (Pb, Hg, Mn and Al); Group 3: 200 mg/kg BP extract + HMM; Group 4: 400 mg/kg BP extract + HMM; Group 5: 800 mg/kg BP extract + HMM. On day 60 animals were euthanized, thyroid was harvested and used for, malondialdehyde MDA, nitric oxide NO, antioxidants, tumor necrosis factor alpha (TNF – α), interleukin 6 (IL – 6), Caspase-3, Nuclear factor erythroid 2- related factor 2 (Nrf2), Nuclear factor kappa B (NfkB) and Heme Oxygynase – 1 (Hmox-1) and histopathology.

Results

There was significant bioaccumulation of Pb, Al, Hg and MN; elevated IL-6 and Tnf-α, MDA and NO, caspase-3 and Nrf2, NF-κB and Hmox-1 in the HMM only group in comparison to the control. There was significant ( p < 0.05) decrease in SOD, CAT GSH activities in HMM only exposed group in comparison to the control deionized water group, whereas BP co-treatment with HMM significantly ( p < 0.05) increased SOD, CAT GSH activities. Co-treatment with BP extract also reversed most of these effects.

Discussion and Conclusions

BP extract may ameliorate HMM -induced thyrotoxicity in female albino rats by blunting oxido-inflammatory activities.

Zn and Se abrogate heavy metal mixture induced ovarian and thyroid oxido-inflammatory effects mediated by activation of NRF2-HMOX-1 in female albino rats

The thyroid is vital for the proper functioning of the female reproductive system since it regulates the metabolism and development of ovary. This is an evaluation of the essential trace elements ETE on the heavy metals mixture HMM mediated oxido-inflammatory effects in the ovary and thyroid of female albino rats. Eight groups (5 female rats /group) were treated as follows for 60 days: Group 1: Deionized water only; Group 2: (Pb, Hg, Mn and Al); Group 3: HMM + ZnCl₂, 0.80 mg/kg; Group 4: HMM + Na₂SeO₃, 1.50 mg/kg; Group 5: HMM + ZnCl₂, 0.80 mg/kg and Na₂SeO₃, 1.50 mg/kg combined. On day 60 animals were euthanized, ovary and thyroid were harvested and used for, MDA, NO, antioxidants, TNF-α, IL-6, HMOX-1, Caspase-3, NF-KB, NRF2, HM and histopathology. There was significant bioaccumulation of Pb, Al, Hg and MN; elevated IL-6 and TNF-α, MDA and NO, caspase-3 and NRF2, NFKB and HMOX-1 with significant decrease in antioxidants in the HMM only group in comparison to the control. Co-treatment with ETE reversed most of these effects. ETE may ameliorate HMM -induced ovarian and thyrotoxicity in female albino rats by blunting oxido-inflammatory activities.

Plant Flavonoids on Oxidative Stress-Mediated Kidney Inflammation

The kidney is susceptible to reactive oxygen species-mediated cellular injury resulting in glomerulosclerosis, tubulointerstitial fibrosis, tubular cell apoptosis, and senescence, leading to renal failure, and is a significant cause of death worldwide. Oxidative stress-mediated inflammation is a key player in the pathophysiology of various renal injuries and diseases. Recently, flavonoids' role in alleviating kidney diseases has been reported with an inverse correlation between dietary flavonoids and kidney injuries. Flavonoids are plant polyphenols possessing several health benefits and are distributed in plants from roots to leaves, flowers, and fruits. Dietary flavonoids have potent antioxidant and free-radical scavenging properties and play essential roles in disease prevention. Flavonoids exert a nephroprotective effect by improving antioxidant status, ameliorating excessive reactive oxygen species (ROS) levels, and reducing oxidative stress, by acting as Nrf2 antioxidant response mediators. Moreover, flavonoids play essential roles in reducing chemical toxicity. Several studies have demonstrated the effects of flavonoids in reducing oxidative stress, preventing DNA damage, reducing inflammatory cytokines, and inhibiting apoptosis-mediated cell death, thereby preventing or improving kidney injuries/diseases. This review covers the recent nephroprotective effects of flavonoids against oxidative stress-mediated inflammation in the kidney and their clinical advancements in renal therapy.

Renoprotective Effects of Luteolin: Therapeutic Potential for COVID-19-Associated Acute Kidney Injuries

Acute kidney injury (AKI) has been increasingly reported in critically-ill COVID-19 patients. Moreover, there was significant positive correlation between COVID-19 deaths and renal disorders in hospitalized COVID-19 patients with underlying comorbidities who required renal replacement therapy. It has suggested that death in COVID-19 patients with AKI is 3-fold higher than in COVID-19 patients without AKI. The pathophysiology of COVID-19-associated AKI could be attributed to unspecific mechanisms, as well as COVID-19-specific mechanisms such as direct cellular injury, an imbalanced renin-angiotensin-aldosterone system, pro-inflammatory cytokines elicited by the viral infection and thrombotic events. To date, there is no specific treatment for COVID-19 and its associated AKI. Luteolin is a natural compound with multiple pharmacological activities, including anticoronavirus, as well as renoprotective activities against kidney injury induced by sepsis, renal ischemia and diverse nephrotoxic agents. Therefore, in this review, we mechanistically discuss the anti-SARS-CoV-2 and renoprotective activities of luteolin, which highlight its therapeutic potential in COVID-19-AKI patients.

Inhibition of the Nrf2 signaling pathway involved in imidacloprid-induced liver fibrosis in Coturnix japonica

Imidacloprid (IMI) is a kind of widely used neonicotinoid insecticide. However, the toxicity of IMI is not only applied to target pests but also causes serious negative effects on birds and other creatures. Our previous studies have shown that long-term exposure to IMI can induce liver fibrosis in quails. However, the specific mechanism of quail liver fibrosis induced by IMI is not completely clear. Accordingly, the purpose of this study is to further clarify the potential molecular mechanism of IMI-induced liver fibrosis in quails. Japanese quails (Coturnix japonica) were treated with/without IMI (intragastric administration with 6 mg/kg body weight) in the presence/absence of luteolin (Lut) (fed with 800 mg/kg) for 90 days. The results reveal that IMI can induce hepatic fibrosis, oxidative stress, fatty degeneration, inflammation, and the down-expression of nuclear factor-E2-related factor-2 (Nrf2). Furthermore, the treatment of Lut, a kind of Nrf2 activator, increased the expression of Nrf2 in livers and alleviated liver fibrosis in quails. Altogether, our study demonstrates that inhibition of the Nrf2 pathway is the key to liver fibrosis induced by IMI in quails. These results provide a new understanding for the study of the toxicity of IMI and a practical basis for the treatment of liver fibrosis caused by IMI.

Procyanidin B2 Alleviates Heat-Induced Oxidative Stress through the Nrf2 Pathway in Bovine Mammary Epithelial Cells

The objective of this study was to investigate the protective effects and potential molecular mechanisms of procyanidin B2 (PB2) in MAC-T (mammary alveolar cells-large T antigen) cells during heat stress (HS). The MAC-T cells were divided into three treatment groups: control (37 °C), HS (42 °C), and PB2 + HS (42 °C). Compared with MAC-T cells that were consistently cultured at 37 °C, acute HS treatment remarkably decreased cell viability, reduced activities of catalase (CAT), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC), and elevated intracellular levels of malondialdehyde (MDA) and reactive oxygen species (ROS). Additionally, nuclear factor erythroid 2-related factor 2 (Nrf2) was activated and translocated to the nucleus, in accompaniment with upregulation of Nrf2, heme oxygenase 1 (HO-1), thioredoxin reductase 1 (Txnrd1), and heat shock protein 70 (HSP70). In parallel, both mRNA transcript and actual protein secretion of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), were increased by heat stress. Pretreatment of MAC-T cells with 0~25 μM PB2 alleviated the decline of cell viability by HS in a dose-dependent fashion and protected cells against HS-induced oxidative stress, as evidenced by significantly improved CAT, SOD, and T-AOC activity, as well as with decreased MDA and ROS generation. Furthermore, PB2 further activated the Nrf2 signaling pathway and reversed the inflammatory response induced by HS. Silencing of Nrf2 by si-Nrf2 transfection not only exacerbated HS-induced cell death and provoked oxidative stress and the inflammatory response, but also greatly abolished the cytoprotective effects under HS of PB2. In summary, PB2 protected MAC-T cells against HS-induced cell death, oxidative stress, and inflammatory response, partially by operating at the Nrf2 signal pathway.

Protective effect of luteolin against chemical and natural toxicants by targeting NF-κB pathway

Humans are continuously exposed to environmental, occupational, consumer and household products, food, and pharmaceutical substances. Luteolin, a flavone from the flavonoids family of compounds, is found in different fruits and vegetables. LUT is a strong anti-inflammatory (via inhibition of NF-κB, ERK1/2, MAPK, JNK, IL-6, IL-8, and TNF-α) and antioxidant agent (reducing ROS and enhancement of endogenous antioxidants). LUT can chelate transition metal ions responsible for ROS generation and consequently repress lipoxygenase. It has been proven that NF-κB, as a commom cellular pathway plays a considerable role in the progression of inflammatory process and stimulates the expression of genes encoding inducible pro-inflammatory enzymes (iNOS and COX-2) and cytokines including IL-1β, IL-6, and TNF-α. This review summarizes the available literature discussing LUT and its potential protective role against pharmaceuticals-, metals-, and environmental compounds-induced toxicities. Furthermore, the review explains the involved protective mechanisms, especially inhibition of the NF-κB pathway.

Peptides Isolated from Yak Milk Residue Exert Antioxidant Effects through Nrf2 Signal Pathway

Food-derived bioactive peptides are considered as the important sources of natural bioactive ingredients. Approximately 3094 peptides were identified by nESI-LC–MS/MS in the hydrolyzed yak milk residue. Peptide KALNEINQF (T10) is the strongest antioxidant peptide. The damage model of H₂O₂-induced human umbilical vein endothelial cells (HUVECs) was used to evaluate the antioxidant effect. After treatment with 25, 50, or 100 μg/mL T10 peptide, T10 obviously decreased H₂O₂-induced damage and increased the cell survival. Comparing with the H₂O₂-induced damage group, superoxide dismutase (SOD) activities were significantly increased 1.03, 1.1, and 1.33 times, and glutathione reductase (GR) activities were significantly increased 1.11, 1.30, and 1.43 times, respectively. Malondialdehyde (MDA) also reduced 1.41, 1.54, and 1.72 times, respectively. T10 inhibited H₂O₂-induced apoptosis in HUVECs, and protein expressions of the apoptosis-related genes bcl-2 and bax were increased and decreased by 1.95 and 1.44 times, respectively, suggesting T10 decreases apoptosis of the mitochondria-dependent pathway. Comparing with the H₂O₂-induced damage group, the RNA expressions of Nrf2, HO-1, and NQO1 were significantly increased by 2.00, 2.11, and 1.94 times; the protein expressions of p-Nrf2, HO-1, and NQO1 were significantly increased by 2.67, 1.73, and 1.04 times; and Keap1 was downregulated by 3.9 and 1.32 times, respectively. T10 also regulated the Nrf2 pathway and expressions of related genes (Keap1, HO-1, and NQO1), and blocking the Nrf2 pathway in the model decreased the protective effect of T10. Taken together, T10 peptide isolated from yak milk residue has a protective effect against H₂O₂-induced damage in HUVECs and the molecular mechanisms are involved in the regulation of Nrf2 signaling pathway and cell apoptosis.

The effect of Luteolin on DNA damage mediated by a copper catalyzed Fenton reaction

Luteolin has been reviewed as a flavonoid possessing potential cardioprotective, anti-inflammatory, anti-cancer activities. Having multiple biological effects, luteolin may act as either an antioxidant or a pro-oxidant. In this work, the protective role of copper(II)-chelation by luteolin on DNA damage via the Cu-Fenton reaction was studied. EPR and UV-vis spectroscopic data demonstrated that the luteolin, lacking 3-OH group, chelates to Cu(II) via the 5-OH and 4-CO groups, respectively. EPR spin trapping experiments using DMPO spin trap confirmed that the coordination of luteolin to Cu(II) significantly suppressed formation of hydroxyl and superoxide radicals (by 80%) in a Cu-Fenton system. Absorption titrations showed that the chelation of Cu(II) by luteolin slightly increased the mild intercalation strength of its interaction with DNA, as compared with free luteolin. Comparison with kaempferol and quercetin revealed, that the strength of the interaction between the free flavonoids/Cu-flavonoid complexes with DNA is only mildly affected by the presence/absence of 3-OH group. Due to the differences in the sensitivities of absorption titrations and viscometry, the latter confirmed weaker DNA intercalating efficiency of Cu-luteolin complex than does free luteolin. A dose dependent protective effect of luteolin against ROS-induced DNA damage was observed using gel electrophoresis. This effect was more pronounced compared to quercetin and kaempferol. In conclusion, the administration of luteolin to patients suffering from oxidative stress-related diseases with disturbed Cu-metabolism such as Alzheimer's diseases (antioxidant effect) and certain cancers (prooxidant effect) may have several health benefits.

Protective Effects of Low-Dose Alcohol against Acute Stress-Induced Renal Injury in Rats: Involvement of CYP4A/20-HETE and LTB4/BLT1 Pathways

Low-dose alcohol possesses multiple bioactivities. Accordingly, we investigated the protective effect and related molecular mechanism of low-dose alcohol against acute stress- (AS-) induced renal injury. Herein, exhaustive swimming for 15 min combined with restraint stress for 3 h was performed to establish a rat acute stress model, which was verified by an open field test. Evaluation of renal function (blood creatinine and urea nitrogen), urine test (urine leukocyte esterase and urine occult blood), renal histopathology, oxidative stress, inflammation, and apoptosis was performed. The key indicators of the cytochrome P450 (CYP) 4A1/20-hydroxystilbenetetraenoic acid (20-HETE) pathway, cyclooxygenase (COX)/prostaglandin E₂ (PGE₂) pathway, and leukotriene B₄ (LTB₄)/leukotriene B₄ receptor 1 (BLT1) pathway were measured by real-time PCR and ELISA. We found that low-dose alcohol (0.05 g/kg, i.p.) ameliorated AS-induced renal dysfunction and histological damage. Low-dose alcohol also attenuated AS-induced oxidative stress and inflammation, presenting as reduced malondialdehyde and hydrogen peroxide formation, increased superoxide dismutase and glutathione activity, and decreased myeloperoxidase, interleukin-6, interleukin-1β, and monocyte chemoattractant protein-1 levels (P < 0.05). Moreover, low-dose alcohol alleviated AS-induced apoptosis by downregulating Bax and cleaved caspase 3 protein expression and reduced numbers of terminal deoxynucleotidyl transferase-mediated dUTP nick-end label-positive cells (P < 0.01). Correlation analysis indicated that 20-HETE was strongly correlated with oxidative stress, while LTB₄ was strongly correlated with inflammation. Low-dose alcohol inhibited AS-induced increases in CYP4A1, CYP4A2, CYP4A3, CYP4A8, and BLT1 mRNA levels and LTB₄ and 20-HETE content (P < 0.01). Interestingly, low-dose alcohol had no effect on COX1 or COX2 mRNA expression or the concentration of PGE₂. Furthermore, low-dose alcohol reduced calcium-independent phospholipase A₂ mRNA expression, but did not affect secreted phospholipase A₂ or cytosolic phospholipase A₂ mRNA expression. Together, these results indicate that low-dose alcohol ameliorated AS-induced renal injury by inhibiting CYP4A/20-HETE and LTB₄/BLT1 pathways, but not the COX/PGE₂ pathway.

Antagonizing effects of curcumin against mercury-induced autophagic death and trace elements disorder by regulating PI3K/AKT and Nrf2 pathway in the spleen

Mercury is a naturally occurring element and highly toxic to humans even at a low dosage. Curcumin is a polyphenol found in turmeric (Curcuma longa), widely used as a treatment strategy to improve antioxidant and anti-inflammatory properties. The purpose of this study was to investigate the potential protective mechanisms of curcumin in spleen damage induced by HgCl₂. The mice were given curcumin by intragastric administration 2 h before HgCl₂ injection for 24 h. At first, splenic transcriptome analysis showed that 3334 genes (2134 up and 1200 down) were differently expressed in HgCl₂-induced spleen damage model. Notably, KEGG enrichment showed phosphatidylinositol 3-kinase (PI3K)-AKT might be a key signaling pathways in HgCl₂-induced spleen damage. Furthermore, our data demonstrated that HgCl₂ could induce autophagic cell death, evidenced by increases the protein expression of PI3K, AKT, LC3-II and p62 and the number of apoptotic cells. Furthermore, we found that curcumin significantly combated autophagic cell death, sodium overload and calcium leak induced by HgCl₂. Simultaneously, further studies demonstrated that curcumin significantly activated nuclear factor (erythroid-derived-2)-like 2 (Nrf2) signaling pathway, and subsequent enhancing antioxidant defenses. Taken together, our data indicated that inorganic mercury could result in autophagic cell death, which may be related to the regulation of PI3K-AKT signaling cascades. Furthermore, Nrf2-mediated antioxidant defenses may be the target of curcumin to confers an adaptive survival response to resist spleen damage induced by HgCl₂. The present study perfects the mechanism theory of HgCl₂-induced spleen damage and provides a way for pharmacological intervention to prevent spleen injury.

Luteolin alleviates inorganic mercury-induced kidney injury via activation of the AMPK/mTOR autophagy pathway

Inorganic mercury is a ubiquitous toxic pollutant in the environment. Exposure to inorganic mercury can cause various poisonous effects, including kidney injury. However, no safe and effective treatment for kidney injury caused by inorganic mercury has been found and used. Luteolin (Lut) possesses various beneficial bioactivities. Here, our research aims to investigate the protective effect of Lut on renal injury induced by mercury chloride (HgCl₂) and identify the underlying autophagy regulation mechanism. Twenty-eight 6-8 weeks old Wistar rats were randomly assigned to four groups: control, HgCl₂, HgCl₂ + Lut, and Lut. We performed the determination of oxidative stress and renal function indicators, histopathological analysis, the terminal deoxynucleotidyl transferase-mediated deoxyuracil nucleoside triphosphate nick-end labeling assay to detect apoptosis, western blot detection of autophagy-related protein levels, and atomic absorption method to detect mercury content. Our results showed that Lut ameliorated oxidative stress, apoptosis and restored the autophagy and renal function caused by HgCl₂ in rats. Concretely, the level of nuclear factor E2-related factor, renal adenosine monophosphate-activated protein kinase (AMPK) expression, and autophagy regulation-related proteins levels were down-regulated, and the mammalian target of rapamycin (mTOR) expression was up-regulated by HgCl₂ treatment. However, Lut treatment reversed the above changes. Notably, Lut reduced the accumulation of HgCl₂ in the kidneys and promoted the excretion of HgCl₂ through urine. Collectively, our results demonstrate that Lut can attenuate inorganic mercury-induced renal injury via activating the AMPK/mTOR autophagy pathway. Therefore, Lut may be a potential biological medicine to protect against renal damage induced by HgCl₂.

Luteolin and cancer metastasis suppression: focus on the role of epithelial to mesenchymal transition

Epithelial to mesenchymal transition (EMT) is a physiological process that assumes a primary role in the induction of cancer metastasis. This results in increased cell renewal, and resistance to cell death and therapies. EMT, therefore, represents an effective strategy for regulating cancerous cell activity. A need for efficacy and low cytotoxicity epithelial to mesenchymal transition modifying drugs has led to the investigational testing of the efficacy of plethora of different groups of phytonutrients. Luteolin is a natural flavonoid inhibits the growth of cancer cells by various mechanisms, such as the stimulation of cancer cell apoptosis, cell cycle arrest, inhibition of cell replication, tumor growth, improvement of drug resistance, prevention of cancer cell intrusiveness and metastasis. This review article focuses on the anti-cancer and anti-metastatic potential of luteolin targeting various transcription factors, markers and signaling pathways associated with the repression of epithelial to mesenchymal transition.

Dibutyl phthalate induces allergic airway inflammation in rats via inhibition of the Nrf2/TSLP/JAK1 pathway

Dibutyl phthalate (DBP), an important plastic contaminant in the environment, is known to cause organ toxicity. Although current research has shown that DBP-induced organ toxicity is associated with oxidative stress, the toxic effect of DBP on the lungs have not been fully elucidated. Therefore, we investigated the potential mechanism by which DBP induces pulmonary toxicity using a model of DBP-induced allergic airway inflammation in rats. The results showed that chronic exposure to DBP induced histopathological damage, inflammation, oxidative stress, apoptosis, and increased the protein levels of thymic stromal lymphopoietin (TSLP) and its downstream protein Janus kinase 1 (JAK1) and signal transducer and activator of transcription 6 (STAT6). Moreover, DBP exposure inhibited nuclear factor-erythroid-2-related factor 2 (Nrf2) and levels of its target genes NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). Additionally, using in vitro experiments, we found that DBP induced oxidative stress, reduced cell viability, and inhibited the Nrf2/HO-1/NQO1 pathway in mouse alveolar type II epithelial cell line. Overall, these data demonstrate that DBP induces allergic airway inflammation in rats via inhibition of the Nrf2/TSLP/JAK1 pathway.

Protection against acute renal injury by naturally occurring medicines which act through Nrf2 signaling pathway

The cellular defense pathway plays a key role in maintaining the homeostasis, tissues and organisms. Nuclear factor E2-related factor 2 (Nrf2), as a key cell signaling pathway, plays an important role in encoding detoxification enzymes and other stress response mediators. Recent studies have shown that it is closely related to the prevention and treatment of acute kidney injury (AKI). Therefore, this article reviews the protective effects of Nrf2-related signaling pathways on acute kidney injury, and summarizes the strategies of natural pharmaceutical ingredients such as flavonoids, alkaloids, terpenes, phenylpropionic acid, polyphenols, and polysaccharides to prevent and treat acute kidney injury. It is of great significance to further study the relationship between Nrf2 regulated signal pathway and kidney disease and the development of new medicines for acute kidney injury treatment. It can also provide new ideas and treatment strategies for clinical treatment of acute kidney injury. PRACTICAL APPLICATIONS: This article reviewed the mechanisms by which the active ingredients of natural medicines slow down acute kidney injury through the Nrf2 pathway. It will help us to understand the regulatory role of the Nrf2 pathway in AKI more comprehensively, and provide a theoretical basis for further exploring the mechanism of more natural drugs to reduce acute kidney injury.

Hexavalent chromium induces mitochondrial dynamics disorder in rat liver by inhibiting AMPK/PGC-1α signaling pathway

Occupational exposure to hexavalent chromium (Cr(VI)) can cause cytotoxicity and carcinogenicity. In this study, we established a liver injury model in rats via intraperitoneal injection of potassium dichromate (0, 2, 4, and 6 mg/kg body weight) for 35 d to investigate the mechanism of Cr(VI)-induced liver injury. We found that Cr(VI) induced hepatic histopathological lesions, oxidative stress, and apoptosis and reduced the expression of mitochondrial-related regulatory factors such as adenosine 5'-monophosphate-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) in a dose-dependent manner. Furthermore, Cr(VI) promoted mitochondrial division and inhibited fusion, leading to increased expression of caspase-3 and production of mitochondrial reactive oxygen species. Our study demonstrates that long-term exposure to Cr(VI) induces mitochondrial dynamics disorder by inhibiting AMPK/PGC-1α signaling pathway in rat liver.

Response of selenoproteins gene expression profile to mercuric chloride exposure in chicken kidney

Kidney is a primary target organ for mercuric chloride (HgCl₂) toxicity. Selenium (Se) can exert antagonistic effect on heavy metals-induced organ toxicity by regulating the expression of selenoproteins. The objective of this study was to investigate the effect of HgCl₂ on the gene expression of selenoproteins in chicken kidney. Sixty male Hyline brown chickens were randomly and evenly divided into two groups. After acclimatization for one week, chickens were provided with the standard diet as well as non-treated water (CON group), and standard diet as well as HgCl₂-treated water (250 ppm, HgCl₂ group). After seven weeks, kidney tissues were collected to examine the mRNA expression levels of 25 selenoproteins genes and protein expression levels of 4 selenoproteins. Moreover, correlation analysis and principal component analysis (PCA) were used to analyze the expression patterns of 25 selenoproteins. The results showed that HgCl₂ exposure significantly decreased the mRNA expression of Glutathione peroxidase 1 (GPX1), GPX4, Thioredoxin reductase 2 (TXNRD2), Iodothyronine deiodinase 1 (DIO1), Methionine-Rsulfoxide reductase 1 (SELR), 15-kDa selenoprotein (SEP15), selenoprotein I (SELI), SELK, SELM, SELN, SELP, SELS, SELT, SELW, and SEPHS2. Meanwhile, HgCl₂ exposure significantly increased the mRNA expression of GPX3, TXNRD1, and SELU. Western blot analysis showed that the expression levels of GPX3, TXNRD1, SELK, and SELN were concordant with these mRNA expression levels. Analysis results of selenoproteins expression patterns showed that HgCl₂-induced the main disorder expression of selenoproteins with antioxidant activity and endoplasmic reticulum resident selenoproteins. In conclusion, selenoproteins respond to HgCl₂ exposure in a characteristic manner in chicken kidney.

Lactobacillus plantarum LP33 attenuates Pb-induced hepatic injury in rats by reducing oxidative stress and inflammation and promoting Pb excretion

Lead (Pb) is one of the most common heavy metals and is harmful to human health. The liver is considered as a major target organ for Pb poisoning. Although probiotics have been shown to alleviate liver injury, the protective effect of Lactobacillus plantarum LP33 (LP33) against Pb-induced hepatotoxicity remains unclear. In order to explore the hepatoprotective effect of LP33, LP33 was administered to Pb-intoxicated Sprague-Dawley rats once daily by oral gavage for 8 weeks. The present results showed that LP33 supplementation alleviated liver injury, and inhibited oxidative stress and inflammation in Pb-exposed rats. Treatment with LP33 also promoted the phosphorylation of adenosine monophosphate-activated protein kinase and protein kinase B, activated nuclear factor erythroid 2-related factor 2 signaling and inhibited the activation of nuclear factor-κB signaling in liver tissues of rats exposed to Pb. Additionally, LP33 exhibited adequate Pb-binding capacity and satisfactory survival under simulated gastrointestinal conditions in vitro, and promoted Pb excretion via enterohepatic circulation of bile acids. This study demonstrated that LP33 reduced Pb-induced oxidative stress and inflammation and promoted Pb excretion, thereby attenuating the Pb-induced hepatic injury. Our findings suggest that LP33 supplementation may be a potential strategy for the treatment of Pb-induced hepatic toxicity.

Brazilian red propolis extract enhances expression of antioxidant enzyme genes in vitro and in vivo

Brazilian red propolis reportedly has reactive oxygen species (ROS) scavenging effects in vitro, but the cellular mechanisms remain unclear. In the present study, the effects of an ethanol extract of Brazilian red propolis (EERP) on the Nrf2-ARE intracellular antioxidant pathway were examined in vitro and in vivo. EERP and its constituents transactivated the reporter gene through the ARE sequence and enhanced the expression of Nrf2-regulated genes in HEK293 cells. It also increased Nrf2 protein in the nucleus, which was partially inhibited by kinase inhibitors. Furthermore, EERP suppressed ROS generation and cytotoxicity induced by tert-butyl hydroperoxide. In vivo, orally administered EERP increased the expression of Nrf2-regulated genes in mice liver. These results suggest that EERP is a potential resource for preventing oxidative stress-related diseases as an Nrf2 inducer.

Deltamethrin induces liver fibrosis in quails via activation of the TGF-β1/Smad signaling pathway

Deltamethrin (DLM) is an important member of the pyrethroid pesticide family, and its widespread use has led to serious environmental and health problems. Exposure to DLM causes pathological changes in the liver of animals and humans and can lead to liver fibrosis. However, the mechanism of DLM-induced liver fibrosis remains unclear. Therefore, to address its potential molecular mechanisms, we used both in vivo and in vitro methods. Quails were treated in vivo by intragastric administration of different concentrations of DLM (0, 15, 30, or 45 mg kg^-1), and the chicken liver cancer cell line LMH was treated in vitro with various doses of DLM (0, 50, 200, or 800 μg mL^-1). We found that DLM treatment in vivo induced liver fibrosis in a dose-dependent manner through the promotion of oxidative stress, activation of transforming growth factor-β1 (TGF-β1) and phosphorylation of Smad2/3. Treatment of LMH cells with different concentrations of DLM similarly induced oxidative stress and also decreased cell viability. Collectively, our study demonstrates that DLM-induced liver fibrosis in quails occurs via activation of the TGF-β1/Smad signaling pathway.

Sulforaphane prevents chromium-induced lung injury in rats via activation of the Akt/GSK-3β/Fyn pathway

Chromium (Cr) is an internationally recognized carcinogenic hazard that causes serious pulmonary toxicity. However, Cr-induced pulmonary toxicity lacks effective treatment to date. Sulforaphane (SFN), a well-known organosulfur compound, has gained increasing attention because of its unique biological function. This study investigates if SFN could decrease K₂Cr₂O₇-induced pulmonary toxicity and a potential mechanism involved using a rat 35-day Cr-induced pulmonary toxicity model and the mouse alveolar type II epithelial cell line (MLE-12). The results showed that SFN prevented Cr-induced oxidative stress, histopathological lesions, inflammation, apoptosis, and changes in protein kinase B (Akt) and glycogen synthase kinase 3 beta (GSK-3β) levels in vivo and in vitro. However, SFN can not play the protective effect against K₂Cr₂O₇-induced cell injury after treating by an Akt-specific inhibitor (MK-2206 2HCl) in MLE-12 cells. Furthermore, SFN increased the expression of nuclear factor-E2-related factor-2 (Nrf2) phase II detoxification enzymes. Collectively, this study demonstrates that SFN prevents K₂Cr₂O₇-induced lung toxicity in rats through enhancing Nrf2-mediated exogenous antioxidant defenses via activation of the Akt/GSK-3β/Fyn signaling pathway. SFN may be a novel natural substance to cure Cr-induced lung toxicity.

The Effects of 50 nm Unmodified Nano-ZnO on Lipid Metabolism and Semen Quality in Male Mice

Fifty male mice were exposed to 50 nm unmodified nano-ZnO through intragastric administration for 90 days to detect the long-term effects of unmodified nano-ZnO in mice. Results showed that the blood glucose, serum follicle stimulating hormone, luteinizing hormone, testosterone, and estradiol were significantly decreased (p < 0.05). The serum triglyceride, total cholesterol, and low-density lipoprotein were significantly increased (p < 0.05). The semen quality of the 160 mg/kg·bw group were significantly lowered (p < 0.05). The liver and testis catalase and CuZn-SOD activities were significantly elevated (p < 0.05). The abilities of •OH inhibition in the livers and testes of the 160 mg/kg·bw group were significantly lowered (p < 0.05). The liver and testis MDA levels of the 160 mg/kg·bw group were significantly elevated (p < 0.05). Results indicate that exposure of nano-ZnO could induce lipid metabolism disorder, hyperlipidemia, and reproductive toxicity to male mice through oxidative injury.

Luteolin protects against lead acetate-induced nephrotoxicity through antioxidant, anti-inflammatory, anti-apoptotic, and Nrf2/HO-1 signaling pathways

Lead (Pb) is one of the most common heavy metal pollutants affecting living organisms. It induces nephrotoxicity with significant alterations in renal structure and function. Luteolin (LUT) a flavonoid present in various plant products is well known for exhibiting numerous pharmacological properties. We evaluated the protective efficacy of LUT against Pb-induced renal injury in male Wistar rats. Four experimental groups: control, LUT (50 mg/kg, orally), PbAc (20 mg/kg, i.p.), LUT + PbAc (at the aforementioned doses) were maintained for 7 days. PbAc administration significantly increased renal Pb accumulation, urea, and creatinine levels in serum, and induced renal histological alterations. Additionally, compared to the control rats, PbAc-treated rats exhibited significantly low levels of antioxidant enzyme activity and expression (SOD, CAT, GPx and GR), as well as high MDA levels. Moreover, PbAc exposure downregulated Nfe212 and Homx1 mRNA expression and significantly increased inflammatory marker (TNF-α, IL-1β and NO) levels in renal tissue. PbAc significantly upregulated the synthesis of apoptotic related proteins and downregulated antiapoptotic protein expression. Notably, LUT pretreatment of PbAc-treated rats provided significant nephroprotection and reversed the alterations in the abovementioned parameters. In conclusion, LUT provided significant protection against PbAc intoxication via antioxidant, anti-inflammatory, and anti-apoptotic activities by activating the Nrf2/ARE signaling pathway.

Imidacloprid-induced liver fibrosis in quails via activation of the TGF-β1/Smad pathway

Imidacloprid (IMI) is one of the most frequently used neonicotinoid insecticide, and its potential toxicity and environmental hazards have gradually attracted people's attention. Liver fibrosis caused by long-term inflammation or oxidative stress can lead to cirrhosis and liver failure, even death. However, the mechanism of liver fibrosis induced by neonicotinoid insecticide remains unclear. This study investigates whether IMI could induce liver fibrosis in quails and a potential mechanism. Our study used a quail 90-day IMI-induced liver fibrosis model. The results showed that IMI induced histopathological lesions, oxidative stress, inflammation, fibrosis, and changes in nuclear factor-kappa B (NF-κB), nuclear factor-E2-related factor-2 (Nrf2), and transforming growth factor (TGF-β1) levels. Furthermore, IMI enhanced the expression of liver fibrosis marker proteins, including collagen I, α-smooth muscle actin (α-SMA), and fibronectin 1 (FN-1), by activating the TGF-β1/Smad signaling pathway. In conclusion, our study demonstrated that IMI exposure induces liver fibrosis via activation of the TGF-β1/Smad signaling pathway in quails.

Lycopene alleviates H2O2-induced oxidative stress, inflammation and apoptosis in bovine mammary epithelial cells via the NFE2L2 signaling pathway

During the transition into lactation, bovine mammary epithelial cells (bMECs) are likely subjected to altered redox balance due to the high metabolic rate associated with the onset of lactation. In non-ruminants, lycopene (LYC), a naturally occurring hydrocarbon carotenoid, has attracted considerable attention as a potential natural agent against oxidative stress. The aim of this study was to investigate whether LYC alleviates oxidative injury in bMECs induced by H2O2 and the underlying molecular mechanisms. The primary bMEC and bovine MEC line MAC-T cells were treated with H2O2 (500 μM) and/or LYC (0.5, 1 or 2 μM) for 24 h. The results showed that treatment with LYC decreased H2O2-induced accumulation of intracellular reactive oxygen species (ROS), inflammatory cytokine (TNF-α, IL-6, and IL-1β) expression and the apoptosis rate. These effects were associated with the activation of the NFE2L2-antioxidant response element (ARE) pathway coupled with inactivation of the nuclear factor-κB (NF-κB) inflammatory and caspase/Bcl2 apoptotic pathways. The bMECs were transfected with NFE2L2 siRNA for 48 h and/or treated with H2O2 (500 μM) and/or LYC (2 μM) for another 24 h. The fact that transfection with NFE2L2 siRNA abrogated the protection of LYC against H2O2-induced accumulation of intracellular ROS, inflammatory cytokine expression and apoptosis suggested that this antioxidant transcription factor is essential for the protective mechanism induced by LYC. These results suggest that LYC might be a potent antioxidant in vivo that could be administered to ruminant animals during stressful periods such as the transition into lactation.

Luteolin Exerts Neuroprotection via Modulation of the p62/Keap1/Nrf2 Pathway in Intracerebral Hemorrhage

Upregulation of neuronal oxidative stress is involved in the progression of secondary brain injury (SBI) following intracerebral hemorrhage (ICH). In this study, we investigated the potential effects and underlying mechanisms of luteolin on ICH-induced SBI. Autologous blood and oxyhemoglobin (OxyHb) were used to establish in vivo and in vitro models of ICH, respectively. Luteolin treatment effectively alleviated brain edema and ameliorated neurobehavioral dysfunction and memory loss in vivo. Also, in vivo, we found that luteolin promoted the activation of the sequestosome 1 (p62)/kelch‐like enoyl-coenzyme A hydratase (ECH)‐associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway by enhancing autophagy and increasing the translocation of Nrf2 to the nucleus. Meanwhile, luteolin inhibited the ubiquitination of Nrf2 and increased the expression levels of downstream antioxidant proteins, such as heme oxygenase-1 (HO-1) and reduced nicotinamide adenine dinucleotide phosphate (NADPH): quinine oxidoreductase 1 (NQO1). This effect of luteolin was also confirmed in vitro, which was reversed by the autophagy inhibitor, chloroquine (CQ). Additionally, we found that luteolin inhibited the production of neuronal mitochondrial superoxides (MitoSOX) and alleviated neuronal mitochondrial injury in vitro, as indicated via tetrachloro-tetraethylbenzimidazol carbocyanine-iodide (JC-1) staining and MitoSOX staining. Taken together, our findings demonstrate that luteolin enhances autophagy and anti-oxidative processes in both in vivo and in vitro models of ICH, and that activation of the p62-Keap1-Nrf2 pathway, is involved in such luteolin-induced neuroprotection. Hence, luteolin may represent a promising candidate for the treatment of ICH-induced SBI.

Ziziphus spina-christi leaf extract attenuates mercury chloride-induced testicular dysfunction in rats

Mercury (Hg) is a heavy metal toxicant, causing several adverse reactions to animals and humans including reproductive dysfunction. The potential protective role of Ziziphus spina-christi leaf extract (ZSCLE) against testicular impairments associated with mercury chloride (HgCl₂) exposure in rats was investigated in the current study. Four experimental groups were employed as follows (n = 7): group I served as control, group II was gavaged with ZSCLE (300 mg/kg), group III was administered with HgCl₂ (0.4 mg/kg), and group IV was preadministered with ZSCLE 1 h before HgCl₂. All groups were treated daily for 28 days. The exposure to HgCl₂ caused a marked increase in Hg concentration in the testicular tissue, which was accompanied with a decrease in testis index. A reproductive impairment was recorded following HgCl₂ exposure as verified through the decrease in levels of testosterone, luteinizing, and follicle-stimulating hormones. HgCl₂ was found to enhance the development of oxidative damage in the testicular tissue as presented by the imbalance between pro-oxidants and antioxidant molecules. In addition, excessive release of tumor necrosis factor-α and interleukin-1β was recorded in response to HgCl₂ intoxication. Furthermore, a disturbance in the apoptotic proteins in favor of the pro-apoptotic proteins was also observed following HgCl₂ intoxication. However, ZSCLE administration along with HgCl₂ abolished significantly the molecular, biochemical, and histopathological alterations induced by HgCl₂ intoxication. Our findings suggest that ZSCLE could be used to mitigate reproductive dysfunction associated with HgCl₂ exposure.

Exploring the kidney hazard of exposure to mercuric chloride in mice:Disorder of mitochondrial dynamics induces oxidative stress and results in apoptosis

Mercury is one of the 10 toxic chemicals with major public health concerns. Continuous exposure to low levels of heavy metals including mercury is related to renal injury, especially in children. This study investigated the possible molecular mechanism of inorganic mercury-induced kidney injury. Twenty eight Kunming mice were divided into four groups (n = 7), and treated with 0, 20, 40, 80 mg/L mercuric chloride (HgCl₂) in drinking water for 16 weeks respectively. All the HgCl₂ exposure mice displayed different degrees of renal injury, which was diagnosed by hematoxylin and eosin stain, biochemical analysis, and ultrastructure examination. The treatment of HgCl₂ inhibited the silent information regulator two ortholog 1 (Sirt1)/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) signaling pathway and resulted the disorder of mitochondrial dynamics, as evidenced by the increasing expression of dynamin-related protein 1 and decreasing expression of mitofusin 2. Meanwhile, HgCl₂ inhibited the nuclear factor erythroid 2-related factor 2 (Nrf2) axis. The abnormality of mitochondrial dynamics and the suppression of Nrf2 axis exacerbated oxidative stress, and then induced cell apoptosis. These findings demonstrated that the disorder of mitochondrial dynamics induced by HgCl₂ activated oxidative stress, and further resulted in renal apoptosis through inhibiting the Sirt1/PGC-1α signaling pathway and the Nrf2 axis.

Recent Advances of Natural Polyphenols Activators for Keap1-Nrf2 Signaling Pathway

The Keap1-Nrf2/ARE signaling pathway is an important defense system against exogenous and endogenous oxidative stress injury. The dysregulation of the signaling pathway is associated with many diseases, such as cancer, diabetes, and respiratory diseases. Over the years, a wide range of natural products has provided sufficient resources for the discovery of potential therapeutic drugs. Among them, polyphenols possess Nrf2 activation, not only inhibit the production of ROS, inhibit Keap1-Nrf2 protein-protein interaction, but also degrade Keap1 and regulate the Nrf2 related pathway. In fact, with the continuous improvement of natural polyphenols separation and purification technology and further studies on the Keap1-Nrf2 molecular mechanism, more and more natural polyphenols monomer components of Nrf2 activators have been gradually discovered. In this view, we summarize the research status of natural polyphenols that have been found with apparent Nrf2 activation and their action modes. On the whole, this review may guide the design of novel Keap1-Nrf2 activator.

Dietary melatonin attenuates chromium-induced lung injury via activating the Sirt1/Pgc-1α/Nrf2 pathway

Exposure to chromium (Cr) causes a number of respiratory diseases, including lung cancer and pulmonary fibrosis. However, there is currently no safe treatment for Cr-induced lung damage. Here, we used in vivo and in vitro approaches to examine the protective effects of melatonin (MEL) on Cr-induced lung injury and to identify the underlying molecular mechanisms. We found that treatment of rats or a mouse lung epithelial cell MLE-12 with MEL attenuated K₂Cr₂O₇-induced lung injury by reducing the production of oxidative stress and inflammatory mediators and inhibiting cell apoptosis. MEL treatment upregulated the expression of silent information regulator 1 (Sirt1), which deacetylated the transcriptional coactivator peroxisome proliferator-activated receptor-γ coactivator-1α (Pgc-1α). In turn, this increased the expression of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) and key anti-oxidant target genes. These results suggest that melatonin attenuates chromium-induced lung injury via activating the Sirt1/Pgc-1α/Nrf2 pathway. Dietary MEL supplement may be a potential new strategy for the treatment of Cr poisoning.

Rutin protects mercuric chloride-induced nephrotoxicity via targeting of aquaporin 1 level, oxidative stress, apoptosis and inflammation in rats

OBJECTIVE

Mercury is a dangerous industrial and environmental pollutant which induces severe damage in diverse organs in animal and humans. The aim of this study was to investigate the protective effect of rutin (50 and 100 mg/kg body weight) against mercuric chloride (HgCl₂) (1.23 mg/kg b.w.) toxicity in rats.

METHODS

The experiment was carried out in male Sprague Dawley rats (n = 35) which was divided into five groups as follow: control, rutin-100, HgCl₂, HgCl₂ + rutin-50 and HgCl₂ + rutin-100.

RESULTS

The results showed that HgCl₂ caused a marked increase in the malondialdehyde (MDA) level and significantly decreased antioxidant enzyme activities (p < 0.05). HgCl₂ also provoked inflammatory responses by elevating the levels of tumor necrosis factor-α (TNF-α), B-cell lymphoma-3 (Bcl-3), interleukin-1β (IL-1β), nuclear factor kappa B (NF-κB), interleukin-33 (IL-33), and activities of mitogen-activated protein kinase 14 (MAPK 14) and myeloperoxidase (MPO) (p < 0.05). HgCl₂ also prompted the apoptotic pathway by increasing the levels of Bcl-2 associated X protein (Bax) and p53, expression of terminal deoxynucleotidyl transferase dUNT nick end labeling (TUNEL) and cysteine aspartate specific protease-3 (caspase-3). HgCl₂ changed histological integrity of kidney and expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG) while caused a decrease in aquaporin 1 (AQP1) water channel protein level. In contrast to this, rutin significantly decreased oxidative stress, apoptosis, inflammation and histopathological alterations while increased AQP1 levels in kidney tissues (p < 0.05).

CONCLUSION

The present study indicated that rutin has a nephroprotective effect due to its anti-inflammatory, antioxidant and antiapoptotic properties.

Delivery of natural phenolic compounds for the potential treatment of lung cancer

The application of natural products to treat various diseases, such as cancer, has been an important area of research for many years. Several phytochemicals have demonstrated anticarcinogenic activity to prevent or reduce the progression of cancer by modulating various cellular mechanisms. However, poor bioavailability has hindered clinical success and the incorporation of these drugs into efficient drug delivery systems would be beneficial. For lung cancer, local delivery via the pulmonary route would also be more effective. In this article, recent in vitro scientific literature on phenolic compounds with anticancer activity towards lung cancer cell lines is reviewed and nanoparticulate delivery is mentioned as a possible solution to the problem of bioavailability. The first part of the review will explore the different classes of natural phenolic compounds and discuss recent reports on their activity on lung cancer cells. Then, the problem of the poor bioavailability of phenolic compounds will be explored, followed by a summary of recent advances in improving the efficacy of these phenolic compounds using nanoparticulate drug delivery systems. Graphical abstract The rationale for direct delivery of phenolic compounds loaded in microparticles to the lungs.