POLYPHENOLS AS A MEANS TO CORRECT OXIDATIVE-NITROSATIVE STRESS IN SKELETAL MUSCLES OF RATS UNDER EXPERIMENTAL METABOLIC SYNDROME

Abstract

The studies were carried out on 35 Wistar white male rats weighing 215-255 g, divided into 5 groups: intact animals (group 1, control I); animals of other groups exposed to round-the-clock illumination (1500 lux during the last 30 days of the experiment) and kept on a carbohydrate-lipid diet (60 days) daily received 1 ml of a 20% aqueous fructose solution (group 2, "placebo", control II), epigallocatechin-3-gallate (group 3, a daily dose of 40 mg/kg), quercetin (group 4, a daily dose of 200 mg/kg), and resveratrol (group 5, a daily dose of 5 mg/kg). The substances were administered intragastrically. Polyphenols were injected together with carbohydrates, a 20% aqueous fructose solution, which increases their solubility and bioavailability. Modelled metabolic syndrome (MS) manifested the development of signs of oxidative-nitrosative stress in the muscles of the thigh: an increase in the superoxide anion radical generation by NADPHand NADHdependent electron transport systems (by microsomal monooxygenases and NO-synthase, by the mitochondrial respiratory chain); elevation in the activity of NO-synthase due to its inducible isoenzyme, and peroxynitrite concentration. The administration of polyphenols (epigallocatechin-3-gallate, quercetin, and resveratrol) over the MS modelling has been found out as an effective means to restrain the signs of oxidative-nitrosative stress in the muscles of the thigh that is confirmed by a decrease in the production of superoxide anion radicals by NADPHand NADH-dependent electron transport systems and constitutive isoform of NO-synthase, by lowered activity of NO-synthase due to its inducible isoform and a fall in the concentration of peroxynitrites. Thus, the capability of bioflavonoids and resveratrol to restrict oxidative-nitrosative stress in skeletal muscles under experimental conditions gives grounds to investigate them as safe and effective means in the therapy and prevention of metabolic syndrome associated with the impact of such factors as the modern "Western diet" and the light regime impairment.