Effect Of High-fat Diet On The Lymphocytes Subsets And The Preventive Effect Of Resveratrol

Obesity is closely related with inflammation, diabetes, cardiovascular disease and otherchronic diseases. Long-term high-fat diet can promote the significant increase of energyintake, leading to the excess energy accumulation in form of fat, which is a significantelement for oxidative stress as well as inflammatory reaction. Study has found that a subset ofthe mice appeared to be sensitive to high-fat diet-induced obesity (DIO), while others werediet-resistant (DR) mice even with the same diet as that of DIO individuals. However, theeffect of redox state on the lymphocyte immunity in the progress of high-fat diet, remainscarce. The aim of the manuscript is to investigate the effect of oxidative stress induced byhigh-fat diet on the energy metabolism and immunity in DIO and DR mice with or withoutantioxidant resveratrol treatment.1. Effect of HFD on the redox state and lymphocyte subsets in DIO and DR miceHigh-fat diet induced obesity mice and resistance mice. Lipids increased and splenicantioxidant ability decreased in DIO mice. Lipids decreased and antioxidant ability increasedin DR mice as compared with DIO mice. The CD3+CD4+/CD3+CD8+subsets percentages andTregs production in peripheral blood and spleen decreased in DIO mice compared with thosein control mice. Splenic FoxP3and TGF-β expressions significantly decreased in DIO mice,and IL7r expression increased. TNF-α, IL-1and IL-6increased and IL-10decreased in thespleen and plasma of DIO mice compared with those in control mice. Splenic MMP-9expression increased significantly and PPARγ expression decreased in DIO mice. There wereno significant differences of MCP-1expressions in all the treated mice. IL-1in plasmaincreased, TNF-α and IL-6in spleen increased in DR mice as compare with those in controlmice. No significant difference were found in the lymphocyte number and function,inflammatory mediators expressions of DR and control mice.0.06%Resveratrolsupplemention significantly decreased the lipids and splenic MDA in DIO mice, decreased theinflammatory cytokines and the expressions of inflammatory mediators, increased Tregsgenes as well as AhR target genes expressions. The effect of0.06%R was more significantlythan0.03%R.2. Effect of oxidative stress induced by HFD on the lymphocyte subsetsPlasma lipid, blood glucose and ROS production increased and antioxidant abilitydecreased in DIO mice. Splenic GSTpi1expression decreased in both DIO and DR mice.TAC increased, blood glucose, plasma lipid, ROS and MDA production decreased in DR miceas compared with those in DIO mice. High-fat diet decreased mitochondrial membranepotential (MMP) in the peripheral blood and spleen of DIO mice, which was significantlyincreased in DR mice as compared with those in DIO mice. HFD decreased theCD3+CD4+/CD3+CD8+subsets percentages in peripheral blood and spleen, and Tregsproduction in the spleen of DIO mice, but not in DR mice. The splenic MMP-7, VCAM-1andTNF-α expression increased significantly in DIO mice, while MMP-7and TNF-α expressionin the spleen of DR mice decreased as compared those in DIO mice. The decreased ROSproduction in DR mice inhibitated apoptosis induced by oxidative stress under HFD feeding compared with DIO mice, thus relieving the inflammatory reaction. Resveratrolsupplemention could decrease ROS production to relieve oxidative stress, it also decreasedthe apoptosis of lymphocytes to relieve the chronic inflammation.3. Effect on the glucose metabolism and lymphocyte subsets in the development ofhigh-fat diet feeding.Plasma insulin and lipids, blood glucose of HF mice evidently increased, antioxidantcapacity decreased after6weeks of HFD and remained thereafter. Also the Tregs productionof peripheral blood and spleen, and the CD3+CD4+/CD3+CD8+subsets percentages in thespleen decreased significantly after6weeks, and this trend continued throughout theexperiment. The body weight increased and the Tregs production decreased after13weeks ofHFD. The splenic Nrf2and PI3K expression increased after6weeks of HFD. The splenicPI3K, AKT, HO-1decreased and the GSK-3β, TNF-α increased after13weeks of HFD.26weeks later, the plasma insulin and lipid decreased significantly, the level of antioxidantcapacity, the CD3+CD4+/CD3+CD8+subsets percentages and the Tregs production in theperipheral blood and spleen increased in DR mice as compared with those in DIO mice.Resveratrol supplementation increased splenic GLUT4and SIRT1expressions, decreasedCOX-2and GSK-3β expressions, decreased the level of blood glucose and plasma insulin,increased the lymphocytes proportion after13weeks of feeding. It increased the antioxidativeenzymes expressions to relieve oxidative stress, and increased the number of lymphocytes torelieve chronic inflammation after26weeks of HFD.4. Effect on the oxidative stress and energy metabolism of T and B lymphocytes in thedevelopment of high-fat diet feedingThe transition rate of T and B lymphocytes decreased significantly since3weeks of HFD.The splenic antioxidative ability of T lymphocytes increased, and the expression of Nrf2andrelated antioxidative enzymes, as well as the expression of PGC-1α increased after3weeks offeeding. Na-K-ATPase expression of B lymphocytes increased after3weeks of HFD, and theATP production increased. The splenic antioxidant ability of B lymphocytes, the expression ofNrf2and related genes, as well as the expression of SIRT1in T and B lymphocytes decreasedsince6weeks of HFD. The expressins of Na-K-ATPase and PGC-1α in T lymphocytes, themitochondrial membrane potential (MMP) decreased, thus accelerating the decrease of ATPproduction. There were no significant difference of the transition rate of T and B lymphocytes,antioxidative capacity and mitochondrial membrane potential among DR and control mice.The expressions of Nrf2as well as the related genes increased in DR mice as compared withthose in DIO mice. The PGC-1α expressions and the ATP production in T and B lymphocytesof DR mice decreased, meanwhile the SIRT1expression in B lymphocytes of DR micedecreased. Resveratrol supplementation significantly increased the splenic transition rate of Tand B lymphocytes since6weeks of feeding. The increased expression of energymetabolism-related genes induced ATP production. After26week of resveratrolsupplementation, the expression of antioxidant genes increased to relieve oxidative stress, andincrease the energy metabolism, thus reducing the apoptosis of T and B lymphocytes. 5. Effect of oxidative stress induced by HFD on the mitochondria biosynthesis andfunction of TregsThe expressions of Tregs genes and the expressions of Nrf2, GST, GCLC, HO-1andNQO1in the Tregs of peripheral blood and spleen in DIO mice decreased, while the ROSproduction of Tregs significantly increased as compared with those in control mice. Increasedoxidative stress in the Tregs of DIO mice aggravated the reduction of PGC-1α, SIRT1, NRF-1and TKT expression. The expressions of Caspase3, DAPK1as well as Bax increased, whilethe expression of Bcl-2decreased, thus promoting the apoptosis of Tregs in DIO mice. Theexpressions of Tregs genes and antioxidant enzymes increased in the Tregs of DR mice, whileROS production of DR mice decreased, thus resulting in the increased expressions of energymetabolism related genes as compared with those in DIO mice. There were no significantdifference in the expression of Tregs apoptosis genes between DR and control mice, and theapoptosis of Tregs in DR mice significantly decreased as compared with those in DIO mice.Resveratrol significantly augmented the expression of antioxidant enzymes, scavenged ROSin Tregs and increased the mitochondria biosynthesis and function to increase energymetabolism, and relieved the injury of Tregs induced by HFD.In summary, the excess ROS production resulted in the injury of mitochondriabiosynthesis and function in DIO mice. Cellular energy metabolism dysfunction was animportant factor of the imblance of lymphocte subsets, and aggravated the chronicinflammation in DIO mice. DR mice could relieve oxidative stress and cellular energymetabolism dysfunction induced by HFD to regulate lymphocyte subsets. Resveratrolsignificantly scavenged the excess of ROS production to relieve oxidative stress, promotedthe mitochondrial energy metabolism to protect the lymphocyte function, and relieved thechronic inflammation.