Tea polyphenols improve glucose metabolism in ceruloplasmin knockout mice via decreasing hepatic iron deposition

ABSTRACT The present study aimed to investigate the role of tea polyphenols (TP) playing in glucose metabolism in male ceruloplasmin knockout mice (CP −/− ), an iron-overloaded model. Compared to wild-type CP +/+ mice, CP −/− mice exhibited hyperglycemia, insulin resistance and excess iron deposition in liver tissue. Increased hepatic oxidative stress (P＜0.05), apoptosis, and reduced gene expression of insulin receptor substrate 2 (IRS2) and glucose transporter 2 (GLUT2) were found in CP −/− mice (P＜0.05). TP treatment may ameliorate hepatic iron overload, oxidative stress and apoptosis, improve insulin sensitivity by upregulating IRS2 and GLUT2 expressions. TP administration could improve glucose homeostasis in CP −/− mice by alleviating hepatic iron-overload, oxidative stress, hepatocyte apoptosis, and restoring insulin signaling pathway. GRAPHICAL ABSTRACT