ABSTRACT
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 (H2O2), IL-1ß, 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, H2O2 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, H2O2, 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, H2O2 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 H2O2 and HOCl production, also reducing the levels of inflammatory cytokines.
Subject(s)
Neutrophils/drug effects , Obesity/immunology , Plant Extracts/pharmacology , Polyphenols/pharmacology , Tea/chemistry , Animals , Antioxidants/pharmacology , CD11b Antigen/metabolism , Catalase/metabolism , Glucosephosphate Dehydrogenase/metabolism , Hexokinase/metabolism , Hydrogen Peroxide/metabolism , Hypochlorous Acid/metabolism , Inflammation , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Male , Neutrophils/metabolism , Peroxidase/metabolism , Phagocytosis/drug effects , RNA, Messenger/metabolism , Rats , Rats, Wistar , Superoxides/metabolism , Toll-Like Receptor 4/metabolism , Tumor Necrosis Factor-alpha/metabolismABSTRACT
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: 30 µM of EGCG, 3 µM of EGC, 2 µM of ECG and 1.4 µM 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-1ß 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.
