title: Green tea catechins ameliorate adipose insulin resistance by improving oxidative stress.
abstract: Epidemiological data have suggested that drinking green tea is negatively associated with diabetes, and adipose oxidative stress may have a central role in causing insulin resistance, according to recent findings. The aim of this work is to elucidate a new mechanism for green tea's anti-insulin resistance effect. We used obese KK-ay mice, high-fat diet-induced obese rats, and induced insulin resistant 3T3-L1 adipocytes as models. Insulin sensitivity and adipose reactive oxidative species (ROS) levels were detected in animals and adipocytes. The oxidative stress assay and glucose uptake ability assay were performed, and the effects of EGCG on insulin signals were detected. Green tea catechins (GTCs) significantly decreased glucose levels and increased glucose tolerance in animals. GTCs reduced ROS content in both models of animal and adipocytes. EGCG attenuated dexamethasone and TNF-α promoted ROS generation and increased glucose uptake ability. EGCG also decreased JNK phosphorylation and promoted GLUT-4 translocation. EGCG and GTCs could improve adipose insulin resistance, and exact this effect on their ROS scavenging functions.
authors.affiliation: State Key Laboratory of Brain & Cognitive Sciences, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, People's Republic of China.
authors.forename: Jingqi
authors.initials: J
authors.lastname: Yan
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Siqingaowa
authors.initials: S
authors.lastname: Suo
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Baolu
authors.initials: B
authors.lastname: Zhao
mesh_terms: D041721:3T3-L1 Cells; D000273:Adipose Tissue / Q000187:drug effects*; D000818:Animals; D002392:Catechin / Q000737:chemistry / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D005260:Female; D005951:Glucose Tolerance Test; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D051379:Mice; D008810:Mice, Inbred C57BL; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013662:Tea / Q000737:chemistry*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D007328:Insulin; D017382:Reactive Oxygen Species; D013662:Tea; D017392:Thiobarbituric Acid Reactive Substances; D002392:Catechin