Sodium humate ameliorates LPS-induced liver injury in mice by inhibiting TLR4/NF-κB and activating NRF2/HO-1 signaling pathways.

BACKGROUND: Acute liver damage is a type of liver disease that has a significant global occurrence and a lack of successful treatment and prevention approaches. Sodium humate (HNa), a natural organic substance, has extensive applications in traditional Chinese medicine due to its antibacterial, anti-diarrheal, and anti-inflammatory characteristics. The purpose of this research was to examine the mitigating impacts of HNa on liver damage induced by lipopolysaccharide (LPS) in mice. METHODS AND RESULTS: A total of 30 female mice were randomly assigned into Con, Mod, L-HNa, M-HNa, and H-HNa groups. Mice in the Con and Mod groups were gavaged with PBS, whereas L-HNa, M-HNa, and H-HNa groups mice were gavaged with 0.1%, 0.3%, and 0.5% HNa, daily. On day 21, Mod, L-HNa, M-HNa, and H-HNa groups mice were challenged with LPS (10 mg/kg). We discovered that pretreatment with HNa improved liver pathological damage and inflammation by inhibiting the toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) signaling pathway, enhancing the polarization of liver M2 macrophages, and reducing the levels of inflammatory cytokines. Our further study found that pretreatment with HNa enhanced the liver ability to combat oxidative stress and reduced hepatocyte apoptosis by activating the nuclear factor erythroid-2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) signaling pathway and enhancing the activities of antioxidant enzymes. CONCLUSIONS: In conclusion, HNa could alleviate LPS-induced liver damage through inhibiting TLR4/NF-κB and activating NRF2/HO-1 signaling pathways. This study is the first to discover the therapeutic effects of HNa on liver damage induced by LPS.

Isolation of Bacillus licheniformis and its protective effect on liver oxidative stress and apoptosis induced by aflatoxin B1.

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins. The use of probiotics is an effective approach to reduce aflatoxins content in foods. To find efficient bacterial species that can eliminate or detoxify AFB1, a bacterial strain S51 capable of degrading AFB1 was isolated from chicken intestine and soil samples by using a culture medium containing coumarin as the sole carbon source. Based on the results of 16S rRNA gene sequence analysis, this isolate (strain S51) was identified as Bacillus licheniformis strain QT338. Further characterization of strain S51 showed that it could degrade AFB1 by 61.3% after incubation at 30°C for 72 h. Additional studies demonstrated that S51 promoted good growth performance of the treated chickens, showed no hemolytic activity, carried few drug resistance genes, and exhibited a certain level of tolerance to acid and bile salts. Furthermore, to verify whether strain S51 exerts a protective effect on AFB1-induced liver injury in chickens and to elucidate the underlying mechanism, a chicken toxicity model was induced with AFB1 (100 µg/kg BW) and treated with S51(1×109CFU/mL) for 12 d. The results showed that S51 decreased the level of alanine transaminase, aspartate transaminase, and total bilirubin (P < 0.05); increased glutathione activity and total antioxidant capacityin the liver induced by AFB1, and decreased malondialdehyde production (P < 0.05). S51 also up-regulated the mRNA expression level of the antioxidant proteins HO-1 and Nrf2 and down-regulated the expression of the oxidation-related factor Keap1 in the Nrf2/Keap1 signaling pathway (P <0.05). S51 inhibited hepatocyte apoptosis induced by AFB1 and decreased the mRNA expression levels of the apoptosis-related genes Bax, caspase-3, caspase-9, and Cyt-C (P < 0.05). These results indicate that S51 regulates apoptosis and alleviates AFB1-induced oxidative stress in chicken liver by controlling the Nrf2/Keap1 signaling pathway.

The impact of high-fat diet consumption and inulin fiber supplementation on anxiety-related behaviors and liver oxidative status in female Wistar rats.

BACKGROUND: Obesity is a worldwide public health problem associated with cognitive and mental health problems in both humans and rats. Studies assessing the effect of fiber supplementation on behavioral deficits and oxidative stress caused by high-fat diet (HFD) consumption in female rats are still scarce. We hypothesized that HFD consumption would lead to anxiety-related behavior and hepatic oxidative stress and that inulin would protect against these changes. We analyzed the impact of HFD-induced obesity combined with fiber supplementation (inulin) on anxiety-related defensive behavior and hepatic oxidative stress. RESULTS: Female rats were fed a high-fat diet (HFD; 45%) for nine weeks to induce obesity. The administration of inulin was found to decrease the adiposity index in both the control and obese groups. The consumption of a HFD combined with inulin supplementation resulted in a reduction in both CAT activity and carbonylated protein levels, leading to a shift in the hepatic redox balance. Interestingly, the behavioral data were conflicting. Specifically, animals that consumed a high-fat diet and received inulin showed signs of impaired learning and memory caused by obesity. The HFD did not impact anxiety-related behaviors in the female rats. However, inulin appears to have an anxiolytic effect, in the ETM, when associated with the HFD. On the other hand, inulin appears to have affected the locomotor activity in the HFD in both open field and light-dark box. CONCLUSION: Our results show that consumption of a HFD induced obesity in female rats, similar to males. However, HFD consumption did not cause a consistent increase in anxiety-related behaviors in female Wistar rats. Treatment with inulin at the dosage used did not exert consistent changes on the behavior of the animals, but attenuated the abdominal WAT expansion and the hepatic redox imbalance elicited by high-fat diet-induced obesity.

Prevention of colitis-induced liver oxidative stress and inflammation in a transgenic mouse model with increased omega-3 polyunsaturated fatty acids.

Inflammatory bowel disease (IBD) is an immune-mediated gut dysfunction, which might also be associated with an inflammatory phenotype in the liver. It is known that the nutritional intake of omega-3 polyunsaturated fatty acids (n-3 PUFA) is inversely correlated to the severity and occurrence of IBD. In order to investigate whether n-3 PUFA can also reduce liver inflammation and oxidative liver damage due to colon inflammation, we explored the dextran sulfate sodium (DSS)-induced colitis model in wild-type and fat-1 mice with endogenously increased n-3 PUFA tissue content. Besides confirming previous data of alleviated DSS-induced colitis in the fat-1 mouse model, the increase of n-3 PUFA also resulted in a significant reduction of liver inflammation and oxidative damage in colitis-affected fat-1 mice as compared to wild-type littermates. This was accompanied by a remarkable increase of established inflammation-dampening n-3 PUFA oxylipins, namely docosahexaenoic acid-derived 19,20-epoxydocosapentaenoic acid and eicosapentaenoic acid-derived 15-hydroxyeicosapentaenoic acid and 17,18-epoxyeicosatetraenoic acid. Taken together, these observations demonstrate a strong inverse correlation between the anti-inflammatory lipidome derived from n-3 PUFA and the colitis-triggered inflammatory changes in the liver by reducing oxidative liver stress.

The Effects of Endoplasmic-Reticulum-Resident Selenoproteins in a Nonalcoholic Fatty Liver Disease Pig Model Induced by a High-Fat Diet.

The present study aimed to investigate the intervention of selenium in the oxidative stress and apoptosis of pig livers, which were induced by a high-fat diet, and the effects of four endoplasmic reticulum (ER)-resident selenoproteins in the process. A 2×4 design trial was conducted that included two dietary fat levels (BD = basal diet and HFD = high-fat diet) and four dietary Se supplementation levels (0, 0.3, 1.0, and 3.0 mg/kg of the diet, in the form of sodium selenite (Na2SeO3)). Our results indicated that the HFD significantly increased the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum, as well as the degree of steatosis, the content of malondialdehyde (MDA), the apoptotic rate, and the level of mRNA caspase-3 in the liver compared to their BD counterparts (p < 0.05). Moreover, these parameters in the HFD groups were more significantly reduced (p < 0.05) for a Se concentration of 1.0 mg/kg than for the other concentrations. Further, for both the BD and HFD, the groups supplemented with 1.0 mg/kg Se showed the highest mRNA level of selenoprotein S. In conclusion, the consumption of an HFD can induce oxidative damage and apoptosis in the liver. This shows that the supplementation of Se at 1.0 mg/kg may be the optimum concentration against damage induced by HFD, and Sels may play a key role in this process.

Magnesium isoglycyrrhizinate alleviates fructose-induced liver oxidative stress and inflammatory injury through suppressing NOXs.

Excessive fructose intake is a risk factor for liver oxidative stress injury. Magnesium isoglycyrrhizinate as a hepatoprotective agent is used to treat liver diseases in clinic. However, its antioxidant effects and the underlying potential mechanisms are still not clearly understood. In this study, magnesium isoglycyrrhizinate was found to alleviate liver oxidative stress and inflammatory injury in fructose-fed rats. Magnesium isoglycyrrhizinate suppressed hepatic reactive oxygen species overproduction (0.97 ± 0.04 a.u. versus 1.34 ± 0.07 a.u.) in fructose-fed rats by down-regulating mRNA and protein levels of nicotinamide adenine dinucleotide phosphate oxidase (NOX) 1, NOX2 and NOX4, resulting in reduction of interleukin-1ß (IL-1ß) levels (1.13 ± 0.09 a.u. versus 1.97 ± 0.12 a.u.). Similarly, magnesium isoglycyrrhizinate reduced reactive oxygen species overproduction (1.07 ± 0.02 a.u. versus 1.35 ± 0.06 a.u.) and IL-1ß levels (1.14 ± 0.09 a.u. versus 1.66 ± 0.07 a.u.) in fructose-exposed HepG2 cells. Furthermore, data from treatment of reactive oxygen species inhibitor N-acetyl-L-cysteine or NOXs inhibitor diphenyleneiodonium in fructose-exposed HepG2 cells showed that fructose enhanced NOX1, NOX2 and NOX4 expression to increase reactive oxygen species generation, causing oxidative stress and inflammation, more importantly, these disturbances were significantly attenuated by magnesium isoglycyrrhizinate. The molecular mechanisms underpinning these effects suggest that magnesium isoglycyrrhizinate may inhibit NOX1, NOX2 and NOX4 expression to reduce reactive oxygen species generation, subsequently prevent liver oxidative stress injury under high fructose condition. Thus, the blockade of NOX1, NOX2 and NOX4 expression by magnesium isoglycyrrhizinate may be the potential therapeutic approach for improving fructose-induced liver injury in clinic.

Redox dyshomeostasis in the experimental chronic hepatic overloads with iron or copper.

Male rats of 80-90 g were overloaded with either Fe(II) or Cu(II) for 42 days by high concentrations of FeCl2 or CuSO4 in the drinking water. The animals were fed with a commercial rodent diet of 2780 kcal/100 g. Both metal treatments led to a liver redox imbalance and dyshomeostasis with oxidative stress and damage and the concomitant enhancement of oxidative processes as indicated by in vivo surface liver chemiluminescence, the sensitive and organ non-invasive assay for oxidative free radical reactions, and by ex vivo determined processes of phospholipid peroxidation and protein oxidation. In parallel, marked decreases in the antioxidant defense were observed. Liver reduced glutathione (GSH) content and the reduced/oxidized glutathione ratio (GSH/GSSG) were early indicators of oxidative metabolic disturbance upon the metal overloads. Thus, GSH plays a central role in the defense reactions involved in the chronic toxicity of Fe and Cu. Chronic overloads of Fe or Cu in rats afford an experimental animal model of hemochromatosis and of Wilson's disease, respectively. These two animal models could be useful in the study and development of the beneficial effects of pharmacological interventions in the two human diseases.

Plastrum Testudinis Extract Mitigates Thiram Toxicity in Broilers via Regulating PI3K/AKT Signaling.

Tibial dyschondroplasia (TD) negatively affects broilers all over the world, in which the accretion of the growth plate (GP) develops into tibial proximal metaphysis. Plastrum testudinis extract (PTE) is renowned as a powerful antioxidant, anti-inflammatory, and bone healing agent. The current study was conducted to evaluate the efficacy of PTE for the treatment of thiram-induced TD chickens. Broilers (day old; n = 300) were raised for 3 days with normal feed. On the 4th day, three groups (n = 100 each) were sorted, namely, the control (normal diet), TD, and PTE groups (normal diet+ thiram 50 mg/kg). On the 7th day, thiram was stopped in the TD and PTE group, and the PTE group received a normal diet and PTE (30 mg/kg/day). Plastrum testudinis extract significantly restored (p < 0.05) the liver antioxidant enzymes, inflammatory cytokines, serum biochemicals, GP width, and tibia weight as compared to the TD group. The PTE administration significantly increased (p < 0.05) growth performance, vascularization, AKT (serine/threonine-protein kinase), and PI3K expressions and the number of hepatocytes and chondrocytes with intact nuclei were enhanced. In conclusion, PTE has the potential to heal TD lesions and act as an antioxidant and anti-inflammatory drug in chickens exposed to thiram via the upregulation of AKT and PI3K expressions.

Copper(II) and iron(III) ions inhibit respiration and increase free radical-mediated phospholipid peroxidation in rat liver mitochondria: Effect of antioxidants.

Rat liver mitochondria (1.5-2.1mg protein·mL-1) supplemented with either 25 and 100µM Cu2+ or 100 and 500µM Fe3+ show inhibition of active respiration (O2 consumption in state 3) and increased phospholipid peroxidation . Liver mitochondria were supplemented with the antioxidants reduced glutathione, N-acetylcysteine or butylated hydroxitoluene, to evaluate their effects on the above-mentioned alterations. Although the mitochondrial dysfunction is clearly associated to phospholipid peroxidation, the different responses to antioxidant supplementation indicate that the metal ions have differences in their mechanisms of toxicity. Mitochondrial phospholipid peroxidation through the formation of hydroxyl radical by a Fenton/Haber-Weiss mechanism seems to precede the respiratory inhibition and to be the main fact in Fe-induced mitochondrial dysfunction. In the case of Cu2+, it seems that the ion oxidizes glutathione, and low molecular weight protein thiol groups in a direct reaction, as part of its intracellular redox cycling. The processes involving phospholipid peroxidation, protein oxidation and mitochondrial respiratory inhibition characterize a redox dyshomeostatic situation that ultimately leads to cell death. However, Cu2+ exposure involves an additional, yet unidentified, toxic event as previous reduction of the metal with N-acetylcysteine has only a minor effect in preventing the mitochondrial damage.

Rat liver mitochondrial dysfunction by addition of copper(II) or iron(III) ions.

Increased copper (Cu) and iron (Fe) levels in liver and brain are associated to oxidative stress and damage with increased phospholipid oxidation process. The aim of this work was to assess the toxic effects of Cu2+ and Fe3+ addition to rat liver mitochondria by determining mitochondrial respiration in states 3 (active respiration) and 4 (resting respiration), and phospholipid peroxidation. Both, Cu2+ and Fe3+ produced decreases in O2 consumption in a concentration-dependent manner in active state 3: both ions by 42% with malate-glutamate as complex I substrate (concentration for half maximal response (C50) 60µM Cu2+ and 1.25mM Fe3+), and with succinate as complex II substrate: 64-69% with C50 of 50µM Cu2+ and with C50 of 1.25mM of Fe3+. Respiratory control decreased with Cu2+ (C50 50µM) and Fe3+ (C50 1.25-1-75mM) with both substrates. Cu2+ produced a 2-fold increase and Fe3+ a 5-fold increase of thiobarbituric acid-reactive substances (TBARS) content from 25µM Cu2+ (C50 40µM) and from 100µM Fe3+ (C50 1.75mM). Supplementations with Cu2+ and Fe3+ ions induce mitochondrial dysfunction with phospholipid peroxidation in rat liver mitochondria. Although is proved that a Fenton/Haber Weiss mechanism of oxidative damage occurs in metal-ion induced mitochondrial toxicity, slightly different responses to the metal ions suggest some differences in the mechanism of intracellular toxicity. The decreased rates of mitochondrial respiration and the alteration of mitochondrial function by phospholipid and protein oxidations lead to mitochondrial dysfunction, cellular dyshomeostasis and cell death.

Effects of Apium graveolens Extract on the Oxidative Stress in the Liver of Adjuvant-Induced Arthritic Rats.

Apium graveolens Linn. (Apiaceae) is an indigenous plant of the North and South Americas, Southern Europe, and Asia and has been widely used as a food or a traditional medicine for treatment of inflammation and arthritis. The purpose of this study was to investigate the antioxidant effects of a methanolic extract of A. graveolens (AGE) against liver oxidative stress in an adjuvant-induced arthritic rat model. The AGE (250, 500, and 1,000 mg/kg) was given orally for 24 consecutive days after induction by injecting complete Freund's adjuvant. Liver and spleen weights were recorded. The superoxide anion level, total peroxide (TP), glutathione peroxidase (GPx) activity, superoxide dismutase (SOD) activity, total antioxidant status, and oxidative stress index (OSI) were also measured. AGE treatment significantly decreased the levels of the superoxide anion, TP, and OSI whereas the GPx and SOD activities significantly increased in the liver of the arthritic rats. These results indicated that AGE showed an ameliorative effect against liver oxidative stress in adjuvant-induced arthritic rats by reducing the generation of liver free radicals and increasing the liver antioxidant enzyme activity.

Effect of 3-keto-1,5-bisphosphonates on obese-liver's rats.

Obesity is associated with an oxidative stress status, which is defined by an excess of reactive oxygen species (ROS) vs. the antioxidant defense system. We report in this present work, the link between fat deposition and oxidative stress markers using a High Fat Diet-(HFD) induced rat obesity and liver-oxidative stress. We further determined the impact of chronic administration of 3-keto-1, 5-BPs 1 (a & b) (40µg/kg/8 weeks/i.p.) on liver's level. In fact, exposure of rats to HFD during 16 weeks induced body and liver weight gain and metabolic disruption with an increase on liver Alanine amino transférase (ALAT) and Aspartate aminotransférase (ASAT) concentration. HFD increased liver calcium level as well as free iron, whereas, it provoked a decrease on liver lipase activity. HFD also induced liver-oxidative stress status vocalized by an increase in reactive oxygen species (ROS) as superoxide radical (O2), hydroxyl radical (OH) and Hydrogen peroxide (H2O2). Consequently, different deleterious damages as an increase on Malon Dialdehyde MDA, Carbonyl protein PC levels with a decrease in non-protein sulfhydryls NPSH concentrations, have been detected. Interestingly, our results demonstrate a decrease in antioxidant enzymes activities such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (GPx) and peroxidases (POD). Importantly, 3-keto-1,5-bisphosphonates treatment corrected the majority of the deleterious effects caused by HFD, but it failed to correct some liver's disruptions as mineral profile, oxidative damages (PC and NPSH levels) as well as SOD and lipase activities. Our investigation point that 3-keto-1,5-bisphosphonates could be considered as safe antioxidant agents on the hepatic level that should also find other potential biological applications.

Causal role of oxidative stress in unfolded protein response development in the hyperthyroid state.

L-3,3',5-Triiodothyronine (T3)-induced liver oxidative stress underlies significant protein oxidation, which may trigger the unfolded protein response (UPR). Administration of daily doses of 0.1mg T3 for three consecutive days significantly increased the rectal temperature of rats and liver O2 consumption rate, with higher protein carbonyl and 8-isoprostane levels, glutathione depletion, and absence of morphological changes in liver parenchyma. Concomitantly, liver protein kinase RNA-like endoplasmic reticulum (ER) kinase and eukaryotic translation initiator factor 2α were phosphorylated in T3-treated rats compared to controls, with increased protein levels of binding immunoglobulin protein and activating transcription factor 4. In addition, higher mRNA levels of C/EBP homologous protein, growth arrest and DNA damage 34, protein disulfide isomerase, and ER oxidoreductin 1α were observed, changes that were suppressed by N-acetylcysteine (0.5 g/kg) given before each dose of T3. In conclusion, T3-induced liver oxidative stress involving higher protein oxidation status has a causal role in UPR development, a response that is aimed to alleviate ER stress and promote cell survival.

Moderate hyperhomocysteinemia provokes dysfunction of cardiovascular autonomic system and liver oxidative stress in rats.

Hyperhomocysteinemia (HHcy) is associated with cardiovascular disease, atherosclerosis and reactive oxygen species generation. Thus, our aim was to investigate whether there was an association between HHcy, blood pressure, autonomic control and liver oxidative stress. Male Wistar rats were divided into 2 groups and treated for 8weeks: one group (control, CO) received tap water, while the other group (methionine, ME) was given a 100mg/kg of methionine in water by gavage. Two catheters were implanted into the femoral artery and vein to record arterial pressure (AP) and heart rate (HR) and drug administration. Signals were recorded by a data acquisition system. Baroreflex sensitivity was evaluated by HR responses to AP changes induced by vasoactive drugs. HR variability and AP variability were performed by spectral analysis in time and frequency domains to evaluate the contribution of the sympathetic and parasympathetic modulation. Lipid peroxidation and antioxidant enzyme activities were evaluated by measuring superoxide dismutase, catalase and glutathione peroxidase in liver homogenates. The ME group presented a significant increase in systolic arterial pressure (118±9 vs 135±6mmHg), diastolic arterial pressure (81±6 vs. 92±4) and mean arterial pressure (95±7 vs. 106±6). In addition, pulse interval variability presented a significant decrease (41%), while the low frequency component of AP was significantly increased (delta P=6.24mmHg(2)) in the ME group. We also found a positive association between lipid peroxidation and cardiac sympathetic modulation, sympathetic and vagal modulation ratio and systolic pressure variability. Collectively, these findings showed that HHcy induced dysfunction of cardiovascular autonomic system and liver oxidative stress.