Melatonin inhibits the expression of the inducible isoform of nitric oxide synthase and nuclear factor kappa B activation in rat skeletal muscle

This study investigated whether the induction of inducible nitric oxide synthase (iNOS) produced by acute exercise in rat skeletal muscle could be prevented by melatonin and whether iNOS down-regulation was related to inhibition of nuclear factor kappaB (NF-kappaB) activation. Male Wistar rats received melatonin i.p. at a dose of 1.0 mg/kg body weight 30 min before being exercised for 60 min on a treadmill at a speed of 25 m/min and a 10% slope. Exercise caused a significant induction of iNOS protein levels and a marked activation of NF-kappaB that were significantly prevented in rats treated with melatonin. Exercise also resulted in increased IkappaB kinasealpha (IKKalpha) and phosphorylated IkappaBalpha protein levels, whereas IkappaBalpha content decreased. These effects were blocked by melatonin administration. The increase in the muscle concentration of thiobarbituric acid reactive substances and in the oxidized/reduced glutathione ratio induced by exercise was partially prevented by melatonin. Our data indicate that melatonin has potent protective effects against damage caused by acute exercise in rat muscle, preventing oxidative stress, NF-kappaB activation and iNOS over-expression. These findings support the view that melatonin treatment, by abolishing the IKK/NF-kappaB signal transduction pathway, might block the production of noxious mediators involved in the inflammatory process.     

Melatonin supplementation ameliorates oxidative stress and inflammatory signaling induced by strenuous exercise in adult human males

Strenuous exercise induces inflammatory reactions together with high production of free radicals and subsequent muscle damage. This study was designed to investigate for the first time and simultaneously whether over-expression of inflammatory mediators, oxidative stress, and alterations in biochemical parameters induced by acute exercise could be prevented by melatonin. This indoleamine is a potent, endogenously produced free radical scavenger and a broad-spectrum antioxidant; consequently, it might have positive effects on the recovery following an exercise session. The participants were classified into two groups: melatonin-treated men (MG) and placebo-treated individuals (controls group, CG). The physical test consisted in a constant run that combined several degrees of high effort (mountain run and ultra-endurance). The total distance of the run was 50 km with almost 2800 m of ramp in permanent climbing and very changeable climatic conditions. Exercise was associated with a significant increase in TNF-α, IL-6, IL-1ra (in blood), and also an increase in 8-hydroxy-2'-deoxyguanosine (8-OHdG) and isoprostane levels (in urine), and indicated the degree of oxidative stress and inflammation induced. Oral supplementation of melatonin during high-intensity exercise proved efficient in reducing the degree of oxidative stress (lower levels of lipid peroxidation, with a significant increase in antioxidative enzyme activities); this would lead to the maintenance of the cellular integrity and reduce secondary tissue damage. Data obtained also indicate that melatonin has potent protective effects, by preventing over-expression of pro-inflammatory mediators and inhibiting the effects of several pro-inflammatory cytokines. In summary, melatonin supplementation before strenuous exercise reduced muscle damage through modulation of oxidative stress and inflammation signaling associated with this physical challenge.     

Age-related differences in the response of the brain to dietary melatonin

The aged brain is prone to excessive levels of immune activity, not initiated by an acute response to an extrinsic agent. While dietary melatonin is reported to attenuate the extent of expression of proinflammatory genes, little is known about the extent to which these changes can be translated into altered levels of corresponding proteins. The baseline levels of the proinflammatory cytokines, tumor necrosis factor alpha (TNF-α) and interleukin-1 alpha, were greater in older (~29 months old) compared to younger (~7 months old) mouse brains. Acute (3 h) exposure to lipopolysaccharide (LPS) induced activation of nuclear factor kappa B (NF-κB), but not inflammatory cytokines in the brain. The serum level of TNF-α was increased after LPS injection, indicating a systemic immune response to the bacterial cell wall component. Dietary melatonin (40 ppm for 9.3 weeks) did not prevent LPS-induced changes in younger animals but caused an increased systemic TNF-α response in older mice. Melatonin did reduce markers of carbonyl formation in brain proteins of young animals and nitrosylative damage to peptide-bound amino acid residues, in the brains of older animals. Acute LPS challenge did not significantly affect these oxidative markers. Thus, despite lack of clear evidence of attenuation of the NF-κB–cytokine inflammatory trajectory within the CNS by melatonin, this agent did show a protective effect against free radical-initiated injury to amino acid residues within proteins. The results illustrate that previously reported changes in gene expression following melatonin treatment need not be closely paralleled by corresponding changes in protein content.     

Salidroside suppresses inflammation in a D-galactose-induced rat model of Alzheimer’s disease via SIRT1/NF-κB pathway

Age-related inflammation is the predominant factor for neurodegenerative diseases like Alzheimer’s disease (AD). In the present study, we examined memory performance and neuroinflammation in D-galactose (D-gal)-induced sub-acute aging model of rats. Our results demonstrated that chronic administration of D-gal (120 mg/kg) produced cognitive impairment as determined by Morris water maze (MWM) test and step-down passive avoidance test. D-gal also activated nuclear factor kappa B (NF-κB) p65/RelA by down-regulating the expression level of sirtuins 1 (SIRT1) in the hippocampus. Treatment with Salidroside (Sal, 20, 40 mg/kg) for 28 days ameliorated D-gal-induced memory deficits and inflammatory mediators including tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). Moreover, D-gal-induced activation of NF-κB signaling pathway in the brain was also inhibited by Sal via up-regulating SIRT1. These results suggest that D-gal-triggered memory impairment and inflammatory response may be associated with SIRT1/NF-κB signaling pathway, whereas treatment with Sal could positively affect these changes in hippocampus.     

Berberine improves airway inflammation and inhibits NF-κB signaling pathway in an ovalbumin-induced rat model of asthma

Objectives: Berberine has been reported for its various activities including anti-inflammatory effects and has been used in treating many diseases. However, its effects on airway inflammation in asthma have not been investigated. This study mainly aimed to detect its effects on the airway inflammation and the nuclear factor-κB (NF-κB) signaling pathway activity in a rat model of asthma. Methods: Asthma was induced by ovalbumin (OVA) sensitization and challenge. The asthmatic rats were respectively treated with vehicle PBS or berberine (100 mg/kg or 200 mg/kg) for 28 days. The control rats were treated with PBS. Inflammatory cells in bronchoalveolar lavage fluid (BALF) were counted and the lung inflammation was scored. Levels of NF-κB p65 (mRNA and protein), phosphorylated NF-κB p65 (p-NF-κB p65), inhibitory κB alpha (IκBα) (mRNA and protein) and phosphorylated IκBα (p-IκBα), as well as NF-κB p65 DNA-binding activity, were measured to assess the activity of NF-κB signaling pathway. Levels of the downstream inflammatory mediators of NF-κB signaling, IL-1β, IL-4, IL-5, IL-6, IL-13 and IL-17 in BALF, were measured. Besides, the serum levels of OVA-specific immunoglobulin (Ig)E were measured. Results: Results showed that OVA increased the number of inflammatory cells in BALF, elevated lung inflammation scores, enhanced the NF-κB signaling activity and promoted the production of IgE in rats. Berberine dose-dependently reversed the alterations induced by OVA in the asthmatic rats. Conclusions: The findings suggested a therapeutic potential of berberine on OVA- induced airway inflammation. The ameliorative effects on the OVA-induced airway inflammation might be associated with the inhibition of the NF-κB signaling pathway.     

The inflammatory balance in human sepsis

Sepsis and its potential degradation into multiple organ failure, reflects a complex immunological process occurring system wide, fueled by local and systemic proinflammatory stimuli, the activity of which is only minimally reflected in the levels of pro- and anti-inflammatory mediators found in the blood. On a cellular level, sepsis encompasses the up-regulation of both pro- and anti-inflammatory pathways. Inflammation is augmented through activation of the intracellular promoter protein nuclear factor κB (NF-κB), which induces synthesis of mRNA coding for many of the pro-inflammatory mediators, including TNF-α, IL-8, and inducible nitric oxide synthase. Similarly, the same stimuli also produce parallel activation of the heat shock protein (hsp) pathways that inhibit NF-κB activation and minimize the inflammatory response. It is the balance between these two pathways that appears to determine the immune responsiveness of the cells both locally and system wide. By characterizing this immune responsiveness, one may understand better the determinants of the ultimate inflammatory response and potential immunotherapy.     

The inflammatory balance in human sepsis

Summary Sepsis and its potential degradation into multiple organ failure, reflects a complex immunological process occurring system wide, fueled by local and systemic proinflammatory stimuli, the activity of which is only minimally reflected in the levels of pro- and anti-inflammatory mediators found in the blood. On a cellular level, sepsis encompasses the up-regulation of both pro- and anti-inflammatory pathways. Inflammation is augmented through activation of the intracellular promoter protein nuclear factor κB (NF-κB), which induces synthesis of mRNA coding for many of the pro-inflammatory mediators, including TNF-α, IL-8, and inducible nitric oxide synthase. Similarly, the same stimuli also produce parallel activation of the heat shock protein (hsp) pathways that inhibit NF-κB activation and minimize the inflammatory response. It is the balance between these two pathways that appears to determine the immune responsiveness of the cells both locally and system wide. By characterizing this immune responsiveness, one may understand better the determinants of the ultimate inflammatory response and potential immunotherapy. Received: 7. Juli 1998 Accepted: 2 November 1998     

The in vivo effect of melatonin on cellular activation processes in human blood during strenuous physical exercise

Melatonin has been reported to have anti- as well as pro-inflammatory properties. Because physical stress is associated with the activation of blood cells, the present study examines melatonin's role in exercise-induced cell activation processes. Eight healthy volunteers (aged 20-62 yr, mean = 31), exercised on an 'Ergometric' bike for 30 min at 80% of their calculated maximum pulse rate. Blood samples were taken just before melatonin administration, directly after exercise, and 2 hr after exercise completion. Cytokine and eicosanoid parameters were measured in plasma from blood stimulated with lipopolysaccharide (LPS) for 2 hr whereas tissue factor (TF) activity was measured in isolated monocytes. Melatonin significantly decreased LPS-induced TF activity by 48% (P < 0.01) directly after exercise, and a 44% reduction was seen 2 hr later (P < 0.02). Furthermore, melatonin significantly reduced the lymphocyte count rise produced directly after exercising by more than 30% (P < 0.01). A trend was also seen for melatonin suppressing the increase of WBC by around 10% and to strengthen the platelet increase by about 8% after physical stress. Melatonin also significantly lowered RBC and hemoglobin counts by 5 and 3-4% during exercise (P < 0.005 and <0.02 respectively). Two hours after exercise, melatonin tended to lower leukotriene B4 levels by 30%. Interleukin-8 and tumor necrosis factor-alpha levels tended to be lower in individuals who had taken melatonin following hard physical activity and a larger sample size may show significance. Thromboxane B2 production seemed unaffected by melatonin during exercise. In conclusion, in vivo intake of melatonin appears to suppress LPS-induced activation of monocytes in whole blood reactions associated with physical exercise and facilitates the down-regulation of inflammatory mediators.     

核因子-κB与冠心病的研究进展

核因子-κB是许多生理和病理生理过程的重要的调节剂,是在炎症和免疫反应及细胞凋亡和增殖中起重要作用的转录因子。近年来,核因子-κB与冠心病的关系得到日益广泛的重视。现就核因子-κB与冠心病的研究进展予以综述。     

Nicotine inhibits tumor necrosis factor-α induced IL-6 and IL-8 secretion in fibroblast-like synoviocytes from patients with rheumatoid arthritis

It was recently demonstrated that the cholinergic anti-inflammatory pathway can modulate host inflammatory responses via cholinergic mediators or via electrical stimulation of the vagus nerve. Here, we investigated whether nicotine, a selective cholinergic agonist, plays any anti-inflammatory role in rheumatoid arthritis fibroblast-like synoviocytes (FLS). We observed that low concentrations (0.1–100 μM) of nicotine did not affect FLS viability in lactate dehydrogenase release test or the MTT assay. Nicotine at concentrations of 0.1–10 μM dose reduced the protein and mRNA expression of IL-6 and IL-8 induced by tumor necrosis factor-α (TNFα). Nicotine also inhibited nuclear factor (NF)-κB (p65) translocation from the cytoplasm to the nucleus, based on Western blotting and immunocytochemical analysis. In conclusion, nicotine can inhibit the TNFα dependant inflammatory pathway in synoviocytes by suppressing the activation of the NF-κB pathway.     

Progress of Study on the Relationship Between Mediators of Inflammation and Apoptosis in Acute Pancreatitis

As an important pathological feature of acute pancreatitis, apoptosis may occur in multiple organs and relate directly to the progression of disease. It is mainly controlled by the apoptosis gene and also influenced by inflammatory mediators. We summarize here the roles of the main inflammatory mediators (e.g., NO, TNF-α, TGF-β1, IL-10, NF-κB) during the pathologic process of acute pancreatitis. We claim that this review is original, and we do not have any financial interest in a company or its competitor, and that all authors meet the criteria for authorship.     

Effects of interleukin-10 on activation and apoptosis of hepatic stellate cells in fibrotic rat liver

AIM:To study the effects of interleukin-10(IL-10)on the expression of α-smooth muscle actin(α-SMA),nuclear factor-κB(NF-κB)and Fas/Fas ligand(FasL)inhepatic stellate cells of experimental rats with hepaticfibrosis.METHODS:Sixty clean SD rats were randomly dividedinto control group(group N),liver fibrotic group(groupC)and IL-10 treatment group(group I).Control groupreceived intraperitoneal injection of saline(2ml·kg~(-1)),twicea week.Fibrotic group was injected intraperitoneallywith 50% carbon tetrachloride(CCl_4)(2 ml·kg~(-1)),twicea week.IL-10 treatment group was given IL-10 at adose of 4 μg·kg~(-1)20 minutes before CCl_4 administrationfrom the third week.Hepatic stellate cells(HSCs)wereisolated from these rats at the seventh and eleventhweeks during the course of liver fibrosis,respectively.The expression of α-SMA and NF-κB in HSCs wasmeasured by S-P immunohistochemistry.The expressionof Fas and FasL mRNA was measured by RT-PCR.Furthermore,liver tissues were harvested from threegroups at the same time.RESULTS:The CCl_4- induced experimental rat hepaticfibrosis model was established successfully.The purityof extracted hepatic stellate cells was about 95% andthe yield of hepatic stellate cells was 1.2-2.3×10~6/g livertissue averagely.The positive expression of α-SMA andNF-κB was 36.5% and 28.5% respectively in group N.The positive levels of α-SMA and NF-κB were increasedsignificantly in group C compared to group N(P<0.01).The positive signals decreased significantly(P<0.05)ingroup I.In the 11~(th)week,the HSCs of group I becameround with visible pyknotic nuclei.The expression ofNF-μB in group C was significantly increased in a time-dependentmanner(P<0.01),but there was no difference in the α-SMA expression(P>0.05).The mRNA of Fasand FasL in group C was significantly increased in a time-dependent manner compared to that in control group.After treated with IL-10,the expression level of Fas andFasL was higher in group I than in group C.CONCLUSION:The positive expression of α-SMA andNF-κB in hepatic stellate cells is decreased by ectogenicIL-10 in liver fibrosis induced by CCl_4.The expression ofFas and FasL is increased in the course of liver fibrosis,and is further increased by IL-10.IL-10 could inhibitthe activation of HSCs and cause apoptosis of activatedHSCs.     

Melatonin induces apoptotic death in LNCaP cells via p38 and JNK pathways: therapeutic implications for prostate cancer

Abstract:  Reactive oxygen species (ROS) are involved in pathophysiology of ischemia/reperfusion injury. Melatonin is a potent scavenger of ROS. Thus, this study was designed to elucidate its effects in a combined hepatic warm ischemia and resection model. The right lateral and caudate lobes (32% of liver volume) of Sprague–Dawley rats underwent warm ischemia for 30 min followed by reperfusion and subsequent resection of the nonischemic liver tissue. Some rats were gavaged with 50 mg/kg melatonin 2 hr before the onset of experiments. Controls received the same volume of microcrystalline cellulose. Survival, transaminases, histology, flow cytometry, inducible nitric oxide synthase (iNOS) expression, and activation of signal transduction pathways [c-Jun N-terminal kinase (JNK), cJUN, IκB kinase α (IKKα), proliferating cell nuclear antigen (PCNA), and Ki67] were assessed for hepatic injury, oxidative stress, and cell proliferation. Melatonin significantly improved animal survival and decreased transaminase levels, the indices for necrosis, liver damage, leukocyte infiltration, and iNOS expression. In parallel, the expression of IKKα, JNK1, and cJUN decreased by 35–50% after melatonin ( P  <   0.05). At the same time, melatonin reduced the expression of both PCNA and Ki67 in liver ( P  <   0.05). Melatonin is hepatoprotective most likely via mechanisms including inhibition of IKK and JNK pathways and regulation of cell proliferation.     

Preventive Effects of Ellagic Acid Against Doxorubicin-Induced Cardio-Toxicity in Mice

Preventive effects of ellagic acid against doxorubicin-induced cardiac oxidative, inflammatory and apoptotic stress were examined. This agent at 0.25, 0.5 or 1 % was added in feed and supplied to mice for 8 weeks, and followed by doxorubicin treatment. Ellagic acid intake increased its deposit in heart. Pre-intake of this compound at 0.5 and 1 % significantly attenuated doxorubicin caused increase in plasma creatine phosphokinase activity. Doxorubicin treatment decreased glutathione content, increased reactive oxygen species (ROS), malonyldialdehyde (MDA), interleukin (IL)-6, IL-10, monocyte chemoattractant protein-1 and tumor necrosis factor-alpha levels, declined glutathione peroxidase (GPX) and superoxide dismutase (SOD) activities, and enhanced xanthine oxidases (XO) activity in heart. Ellagic acid intake dose-dependently reserved glutathione content, lowered ROS and MDA levels, and reduced XO activity. This compound at 0.5 and 1 % retained GPX and SOD activities, and decreased cytokines in heart. Doxorubicin treatment raised cardiac activity and protein production of caspase-3, nuclear factor kappa B (NF-κB) p50 and p65. Ellagic acid dose-dependently lowered caspase-3 activity and cleaved caspase-3 formation, and at 0.5 and 1 % declined activity and protein level of NF-κB. Doxorubicin treatment also up-regulated cardiac expression of p-p38, p-ERK 1/2 and p-JNK, and ellagic acid at 0.5 and 1 % suppressed p-p38 expression and at 1 % down-regulated p-ERK 1/2 expression. These findings suggest that ellagic acid is a potent cardiac protective agent against doxorubicin.