EFFECT OF CURCUMIN ON THE DEVELOPMENT OF OXIDATIVE-NITROSATIVE STRESS IN THE LIVER TISSUES OF RATS EXPOSED TO MODELED METABOLIC SYNDROME UNDER ROUND-THE-CLOCK LIGHTING

Abstract

The aim of this study is to evaluate the effect of curcumin, a natural polyphenol, on indicators of oxidative-nitrosative stress in the liver of rats exposed to modeled metabolic syndrome (MS) under 24-hour lighting. The experiments were performed on 21 Wistar male white rats weighing 215-255 g. The animals were divided into 3 groups of 7 animals in each. The animals of the 1st group (control I) were kept on a standard vivarium diet and an ordered alternation of light / dark periods. The rats of the 2nd group were used for modeling diet-induced MS (a 2-month carbohydrate-lipid diet including 20% aqueous fructose solution for drinking and appropriate food) under the 24-hour lighting (control II). The rats of the 3rd group received curcumin (Sigma-Aldrich, Inc., USA) intragastrically through a gavage in a dose of 200 mg/kg daily during the 24-hour lighting exposure. We investigated the liver homogenate of rats to assess the rate of generation of the superoxide anion radical (•О), the activity of total NO synthase (NOS), its constitutive and inducible isoforms (cNOS, iNOS), and the content of peroxynitrites of alkali and alkaline earth metals. The administration of curcumin under the experimental conditions significantly suppresses the •О production in liver tissues by microsomal monooxygenases and NOS by 40.1%, by the mitochondrial respiratory chain by 34.4%, and by leukocyte NADPH oxidase by 32.1%; the activity of NOS and iNOS by 39.0% and 41.6%, the concentration of peroxynitrites of alkaline and alkaline earth metals by 23.8 compared to the values in the 2nd group. The activity of cNOS under these conditions was 2.79 times higher than the respective results in the II control, and the coupling index of this isoenzyme was 4.3 times higher. The main conclusion that can be drawn is that the administration of curcumin in the rat model of MS under the round-the-clock lighting significantly reduces the signs of oxidative-nitrosative stress in the liver tissues.