Cocoa intake ameliorates hepatic oxidative stress in young Zucker diabetic fatty rats

Abstract

Chronic hyperglycemia in diabetes is associated with oxidative stress-mediated tissue damage. The present study is aimed to explore the role of a cocoa-enriched diet in ameliorating the oxidative stress-induced damage in the liver of young type 2 diabetic Zucker diabetic fatty (ZDF) rats. Male ZDF rats were fed a control or cocoa-rich diet (10%), and Zucker Lean (ZL) animals received the control diet. ZDF rats fed with cocoa (ZDF-Ca) decreased body weight gain, glucose and insulin levels, and improved glucose tolerance and insulin resistance. Cocoa diet further reduced reactive oxygen species (ROS) levels and carbonyl content in the liver of ZDF animals. The diminished activity of superoxide dismutase (SOD) and the enhanced activity of heme oxygenase (HO-1) in ZDF-C were returned to ZL values upon cocoa administration. Cocoa did not restore the decreased glutathione-S-transferase (GST) activity in both ZDF groups in comparison to ZL rats. Glutathione (GSH) content and activities of glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (CAT) remained unaltered among all animal groups. Moreover, cocoa-rich diet suppressed total and phosphorylated nuclear factor erythroid-derived 2-like 2 (Nrf2), as well as p65-nuclear factor-kappaB (NF-ĸB) enhanced levels observed in ZDF rats. The results indicate that cocoa protects the hepatocytes by improving the antioxidant competence in the liver of young type 2 diabetic ZDF rats.