Background/Aims. Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome. It is currently the most common chronic liver disease with complex ...pathogenesis and challenging treatment. Here, we investigated the hepatoprotective role of green tea (GT) and determined the involvement of miRNAs and its mechanism of action. Methods. Male C57Bl/6 mice were fed with a high-fat diet for 4 weeks. After this period, the animals received gavage with GT (500 mg/kg body weight) over 12 weeks (5 days/week). HepG2 cell lines were transfected with miR-34a or miR-194 mimetics and inhibitors to validate the in vivo results or were treated with TNF-α to evaluate miRNA regulation. Results. GT supplementation protects against NAFLD development by altering lipid metabolism, increasing gene expression involved in triglycerides and fatty acid catabolism, and decreasing uptake and lipid accumulation. This phenotype was accompanied by miR-34a downregulation and an increase in their mRNA targets Sirt1, Pparα, and Insig2. GT upregulated hepatic miR-194 by inhibiting TNF-α action leading to a decrease in miR-194 target genes Hmgcs/Apoa5. Conclusion. Our study identified for the first time that the beneficial effects of GT in the liver can be due to the modulation of miRNAs, opening new perspectives for the treatment of NAFLD focusing on epigenetic regulation of miR-34a and miR-194 as green tea targets.
•Effect of catechins alone/combined on functional parameters of human neutrophils.•Catechins reduced inflammatory parameters.•Catechins suppressed TLR4 and NFκB expression, and decreased cytokine ...release.•Each catechin in the green tea presents marked modulatory actions.•Catechins present immunomodulatory actions, either alone or in combination.
The purpose of this study was to evaluate the potential of a mixture containing the four main catechins found in green tea, as well it separately, as modulators of the functional parameters of human neutrophils. The cells were obtained from peripheral blood of healthy individuals isolated and cultured with a mix: 30μM of EGCG, 3μM of EGC, 2μM of ECG and 1.4μM of EC, as well as each one alone. We evaluated the cytotoxicity of catechins, production of several reactive oxygen species (ROS), antioxidant enzymes (SOD, CAT, GPx and GR), Nrf2, TLR4/IKK/NFκB, CD11b mRNA levels, intracellular calcium release, chemotactic and phagocytic capacity, myeloperoxidase (MPO), and G6PDH activities, hypochlorous acid (HOCl) and pro-inflammatory cytokines release, protein levels of TLR4, p38 MAPK, iNOS and p-65 NFκB. The actions of the catechins were evidenced by the reduction in inflammatory parameters, including the suppression of TLR4, NFκB and iNOS protein expression, decreased release of TNF-α, IL-1β and IL-6, migration capacity, MPO activity and HOCl production and the suppression of ROS, nitric oxide and peroxynitrite production, while inducing antioxidant enzyme activities and Nrf2 mRNA levels, phagocytic capacity and calcium release. Our results demonstrate that catechins present marked immunomodulatory actions, either alone or in combination.
This study aimed to investigate whether green tea polyphenols (GT) modulate some functional parameters of lymphocytes from obese rats. Male Wistar rats were treated with GT by gavage ...(12weeks/5days/week; 500mg/kg of body weight) and obesity was induced by cafeteria diet (8weeks). Lymphocytes were obtained from mesenteric lymph nodes for analyses. In response to the cafeteria diet we observed an increase in activity of the metabolic enzyme hexokinase, ROS production, MnSOD, CuZnSOD and GR enzyme activities and proliferation capacity of the cells (baseline), whereas IL-10 production was decreased. Obese rats treated with GT decreased cell proliferation (under ConA stimulation). Hexokinase and G6PDH activity, ROS production and MnSOD, CuZnSOD, GPx and GR enzymes remained increased, accompanied by an increase in Nrf2 mRNA level. There was a decrease in pro-inflammatory IL-2, IL-6, IL-1β, TNF-α cytokines that were accompanied by a decrease in the mRNA level of TRL4 while IL-10 production was increased in obese rats treated with GT. GT treatment of lean rats showed similar results to that of obese rats treated with GT, indicating that the effects of GT are independent of diet. Foxp3 and IRF4 mRNA levels were increased by GT. In conclusion, cafeteria diet modulated the function of lymphocytes from lymph nodes, increasing ROS production and decreasing anti-inflammatory IL-10, which could contribute to the inflammatory state in obesity. GT reduced ROS production, improving the redox status and reducing pro-inflammatory cytokine production by lymphocytes, suggesting that GT treatment may be driving lymphocytes to a more anti-inflammatory than pro-inflammatory microenvironment.
•Obese condition increased lymphocyte ROS production and decreased IL-10 release.•Obese rats treated with green tea (GT) decreased cell proliferation and ROS production.•GT treated rats reduced ROS, pro-inflammatory cytokines and improved redox status.•GT may be driving lymphocytes to a more anti-inflammatory microenvironment.•We reinforce the importance of natural compounds as immunomodulatory mediators.
•Firefighters were supplemented with resveratrol (100mg) and applied a fitness test.•RES increased glucose and triglycerides in firefighters after the fitness test.•IL-6 and TNF-α were decreased in ...the RES group after the fitness test.•Fitness test applied was not sufficient to challenge the antioxidant defense systems.•100mg of RES for three months did not induce significant effects.
The purpose of this study was to determine the plasma metabolic response and certain indicators of oxidative stress (antioxidant system and oxidative stress biomarkers) in plasma and erythrocytes of Brazilian military firefighters supplemented or not with resveratrol (RES) for 90days (100mg/day). The analyses were performed before and after a typical physical fitness test (FT) used to induce oxidative stress.
In this placebo-controlled double-blinded study, we observed that RES supplementation did not present hepatic consequences compared with the placebo group following analysis of AST, ALT and GGT plasma activities. Plasma glucose and triglycerides levels were increased after the FT in firefighters supplemented with RES but were not elevated at baseline. Neither total nor cholesterol fractions were modified by RES supplementation. CK levels were increased after the firefighters performed the FT; however, no differences were determined between the placebo and RES groups. Ferric-reducing ability of plasma as well as uric acid was increased after the FT, but was not modified by RES supplementation. Plasma oxidative stress biomarkers, such as thiol content, 8-isoprostane and 8OHdG, showed no modifications, while IL-6 and TNF-α were decreased in the RES group after the FT. Among antioxidant enzyme activities determined in erythrocytes from the firefighters, only GPx activity was reduced by RES supplementation both before and after the FT.
In summary, the most pronounced effect of RES supplementation is its anti-inflammatory effect, which reduced IL-6 and TNF-α level. The FT applied to Brazilian military firefighters was not sufficient to challenge the antioxidant defense systems, and, therefore, 100mg of RES for three months did not induce significant effects.
► We evaluated the oxidative stress in human lymphocytes induced by a FA mixture and the protective role of ASTA. ► FA mixture increased ROS production, oxidative stress and proliferative capacity of ...B-lymphocytes. ► ASTA decreased the proliferative capacity of cells not by reducing intracellular calcium concentration. ► ASTA partially prevent oxidative stress induced by FA by blenching/quenching free radical production.
Fatty acids (FA) have been shown to alter leukocyte function, and depending on concentration and type, they can modulate both inflammatory and immune responses. Astaxanthin (ASTA) is a carotenoid that shows notable antioxidant properties. In the present study we propose to evaluate the oxidative stress in human lymphocytes induced by a FA mixture and the possible protective role of ASTA. The present study showed that the FA mixture at 0.3mM caused a marked increase in the production of superoxide anion, hydrogen peroxide and nitric oxide, which was accompanied by an increase in total-SOD activity, in TBARS levels and a reduction of catalase activity and content of GSH and free thiol groups. The FA mixture also promoted an increase in intracellular Ca2+ mobilization and in the proliferative capacity of B-lymphocytes. The addition of ASTA (2μM) partially decreased the ROS production and TBARS levels and increased the levels of free thiol groups. ASTA decreased the proliferative capacity of cells treated with FA but not by reducing intracellular calcium concentration. Based on these results we can conclude that ASTA can partially prevent oxidative stress in human lymphocytes induced by a fatty acid mixture, probably by blenching/quenching free radical production.
Purpose
Our study aimed to evaluate whether obesity induced by cafeteria diet changes the neutrophil effector/inflammatory function and whether treatment with green tea extract (GT) can improve ...neutrophil function.
Methods
Male Wistar rats were treated with GT by gavage (12 weeks/5 days/week; 500 mg/kg of body weight), and obesity was induced by cafeteria diet (8 weeks). Neutrophils were obtained from the peritoneal cavity (injection of oyster glycogen). The following analyses were performed: phagocytic capacity, chemotaxis, myeloperoxidase activity (MPO), hypochlorous acid (HOCl), superoxide anion (O
2
·−
), hydrogen peroxide (H
2
O
2
), IL-1β, IL-6 and TNFα, mRNA levels of inflammatory genes, calcium mobilisation, activities of antioxidant enzymes, hexokinase and G6PDH.
Results
Neutrophils from obese rats showed a significant decrease in migration capacity, H
2
O
2
and HOCl production, MPO activity and O
2
·−
production. Phagocytosis and CD11b mRNA levels were increased, while inflammatory cytokines release remained unmodified. mRNA levels of TLR4 and IκK were enhanced. Treatment of obese rats with GT increased neutrophil migration, MPO activity, H
2
O
2
, HOCl and O
2
·−
production, whereas TNF-α and IL-6 were decreased (versus obese). Similar reductions in TLR4, IκK and CD11b mRNA were observed. Catalase and hexokinase were increased by obesity, while SOD and G6PDH were decreased. Treatment with GT reduced catalase and increased the GSH/GSSG ratio.
Conclusion
In response to a cafeteria diet, we found a decreased chemotaxis, H
2
O
2
release, MPO activity and HOCl production. We also showed a significant immunomodulatory effect of GT on the obese condition recovering some of these factors such H
2
O
2
and HOCl production, also reducing the levels of inflammatory cytokines.
Aim
To evaluate the effect of administration of astaxanthin (ASTA) and fish oil (FO) on enzymatic antioxidant parameters of dental pulp tissue from healthy rats.
Methodology
Thirty‐two healthy Wistar ...rats were divided into four groups: untreated control, ASTA‐treated (1 mg kg−1 body weight), FO‐treated (10 mg eicosapentaenoic acid per kg BW and 7 mg docosahexaenoic acid per kg BW) and FO plus ASTA‐treated. A prophylactic dose was administered in each group daily by gavage, 5 days a week, for 45 days. After treatment, the rats were killed and all incisor dental pulps were removed. Superoxide dismutase (SOD), catalase, glutathione (GSH) peroxidase and reductase activities were determined. Data were compared by anova and the Tukey's post‐test (
P
< 0.05).
Results
Treatment with FO, ASTA and FO plus ASTA caused a reduction in SOD and GSH reductase activities in dental pulp tissue compared to untreated control rats (
P
< 0.05). ASTA partially stimulated catalase activity.
Conclusions
The preventive administration of ASTA and FO changed the enzymatic antioxidant system of dental pulp tissue, possibly by controlling oxidative stress.
Leite MF, de Lima A, Massuyama MM, Otton R.
In vivo astaxanthin treatment partially prevents antioxidant alterations in dental pulp from alloxan‐induced diabetic rats. International Endodontic ...Journal, 43, 959–967, 2010.
Aim To evaluate the effect of astaxanthin on antioxidant parameters of dental pulp from diabetic rats. The hypothesis tested was that supplementation of diabetic rats with astaxanthin might eliminate, or at least attenuate, the defect in their antioxidative status.
Methodology Wistar rats (n = 32) were divided into four groups: untreated control, treated control, untreated diabetic and treated diabetic rats. A prophylactic dose of astaxanthin (20 mg kg−1 body weight) was administered daily by gavage for 30 days. On day 23, diabetes was induced by injection of alloxan (60 mg kg−1 body weight). After 7 days of diabetes induction, the rats were killed, and pulp tissue from incisor teeth removed. Superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and reductase activities were determined. Data were compared by anova and the Newman–Keuls test (P < 0.05).
Results Diabetes caused a reduction in SOD, GPx and reductase activity in dental pulp tissue. Astaxanthin had no effect on SOD and catalase activities; however, it stimulated GPx in control and diabetic rats.
Conclusions Diabetes altered the antioxidant system in dental pulp tissue; astaxanthin partially improved the diabetic complications.
► Effect of methylglyoxal/high glucose on neutrophils functional parameters. ► Also, if the addition of astaxanthin with vitamin C modulates those parameters. ► Methylglyoxal/high glucose promote an ...injury to the function of neutrophils. ► Astaxanthin with vitamin C proved to be a powerful antioxidant in human neutrophils. ► Association of astaxanthin/vitamin C improved neutrophil function and redox status.
The purpose of the present study was to find out whether co-treatment of human neutrophils with high glucose and methylglyoxal (MGO) can alter the biochemical parameters of human neutrophils. We also examined if astaxanthin associated with vitamin C can improve those biochemical parameters. Neutrophils from healthy subjects were treated with 20mM of glucose and 30μM MGO followed or not by the addition of the antioxidants astaxanthin (2μM) and vitamin C (100μM). MGO/high glucose treatment reduced the phagocytic capacity and the G6PDH, total/SOD and GR activities. Additionally, there was an increase in the activity of myeloperoxidase (MPO) with consequent increase in the hypochlorous acid production, CAT activity and in the release of IL-6 cytokine without changes in intracellular calcium mobilization. Our study also shows that the association of astaxanthin with vitamin C greatly improved neutrophil phagocytic capacity, decreasing all reactive oxygen species measured, pro-inflammatory IL-1β and TNF-α release, MPO activity and HClO production. The combination of astaxanthin with vitamin C alone has more antioxidant and anti-inflammatory effects than when they were in the presence of MGO/high glucose. Injury to the function of neutrophils due to high glucose and methylglyoxal appears not to involve oxidative stress or calcium release. The association of antioxidants astaxanthin and vitamin C promoted a significant improvement in the function of neutrophils and in the redox status.
Diabetes induces apoptosis in lymphocytes Otton, R; Soriano, F G; Verlengia, R ...
Journal of Endocrinology/Journal of endocrinology,
07/2004, Letnik:
182, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The occurrence of DNA fragmentation in lymphocytes obtained from alloxan-induced diabetic rats and diabetic patients was investigated. A high proportion of apoptotic lymphocytes in diabetic states ...may explain the impaired immune function in poorly controlled diabetic patients. Rat mesenteric lymph node lymphocytes were analysed for DNA fragmentation by using flow cytometry and agarose gel, and for chromatin condensation by Hoescht 33342 staining under different situations. Immediately after being obtained, the proportion of lymphocytes with fragmented DNA was twofold higher in alloxan-induced diabetic rats than in cells from control rats. After 48 h in culture, the occurrence of DNA fragmentation was also higher (81%) in cells from diabetic rats. Hoescht staining and fragmented DNA visualized in agarose gel were also higher in lymphocytes from alloxan-induced diabetic rats than in control cells. To investigate if this phenomenon also occurs in humans, blood lymphocytes from 14 diabetic subjects were examined. Similar results to those of rat lymphocytes were found in cells from diabetic patients immediately after being obtained and after 48 h in culture. The high occurrence of apoptosis in lymphocytes was accompanied by a reduced number of blood-circulating lymphocytes in diabetic patients. The involvement of low insulinaemia for the occurrence of apoptosis in lymphocytes was also examined. Insulin treatment markedly reduced the proportion of lymphocytes with fragmented DNA in alloxan-induced diabetic rats.
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