Alterations in Antioxidant Defence Systems and Metal Profiles in Liver of Rats with Metabolic Syndrome Induced with High-Sucrose Diet

Abstract

Metabolic syndrome (MetS) is a combination of several different metabolic disorders and considered one of the major public health problems worldwide. The underlying causes of MetS include being overweight and obesity, physical inactivity, and genetic factors. We aimed to examine the alterations in the levels of biomarkers of oxidative stress, activities of antioxidant defense enzymes, and metal contents of the liver in rats with MetS. Rats in control and MetS groups were fed with standard rat chow-drinking water and standard rat chow - 32% sucrose solution (instead of drinking water) ad libitum for 16 weeks, respectively. Following the confirmation of MetS, antioxidant enzyme activities and malondialdehyde (MDA), 3-nitrotyrosine (3-NT), phospho-Akt (pSer473) levels were measured in the homogenates of the liver. Distributions of elements in the liver were also analyzed. The stained hepatic tissue slides were examined by light microscopy. The activities of catalase and glutathione-S-transferase were significantly decreased in MetS-group (about 15% and 29%, respectively) compared to the control group, while the glutathione reductase activity and MDA and 3-NT levels were significantly increased (as the levels of 78%, 26%, and 67%, respectively) (p<0.05). The hepatocytes in the MetS group showed mild diffuse microvesicular steatosis. Furthermore, Cu, Fe, and Mn levels were significantly high in MetS-group while Zn level was significantly low compared to the control group. Our results showed increased oxidative stress, impaired antioxidant defense enzyme activities, and altered metals’ metabolisms which may have an important role in the pathogenesis of MetS.