Search

The study is aimed at investigating the impact of exogenous melatonin and quercetin on indices of systemic inflammatory response and indicators of carbohydrate and lipid metabolism in the blood serum of male rats exposed to round-the-clock lighting (RCL) with 1500 lx intensity during the last 30 days of being kept on a 60 day high-calorie carbohydrate-lipid diet (HCCLD, 20% fructose solution and the proper chow). The study has demonstrated that the restoration of serum melatonin concentration in rats by its exogenous administration during the RCL exposure and keeping them on HCCLD did not fully correct the indicators of the systemic inflammatory response such as the content of tumor necrosis factor α (TNF-α) and C-reactive protein (CRP), as well as indices of carbohydrate and lipid metabolism such as concentration of insulin, highdensity lipoprotein (HDL), very low-density lipoprotein (VLDL) and triglycerides, HOMA-IR insulin resistance index. The administration of quercetin under the experimental conditions was accompanied by a significant increase in the serum melatonin concentration (by 85.9%), a decrease in the content of TNF-α (by 53.9%), CRP (by 54.4%), glucose (by 49.2%), insulin (by 49.6%), VLDL (by 49, 2%) and triglycerides (by 49.3%), and an increase in HDL concentration (by twofold), but these indicators (with the exception of the HOMA-IR index, which decreased by 62.4%) did not reach the values of the intact group. The combined effect of melatonin and quercetin under RCL exposure and HLLD significantly improved the indicators of systemic inflammatory response, carbohydrate and lipid metabolism that is confirmed by a more significant decrease in serum levels of TNF-α, CRP, insulin, VLDL and triglycerides, an increase in HDL concentration, and a decrease in the HOMA-IR index compared with the separate use of melatonin and quercetin. [ABSTRACT FROM AUTHOR]

This article describes the effect of NF-κB inhibitor ammonium pyrrolidine dithiocarbamate and Nrf2 inducer dimethylfumarate on indicators of oxidative-nitrosative stress in skeletal muscles of rats with chronic hypomelatoninemia, induced by round-the-clock illumination with an intensity of 1500 lux for 30 days, against the background of a carbohydrate-lipid diet (20% fructose solution and appropriate food) for 60 days. The study demonstrated that the administration of ammonium pyrrolidine dithiocarbamate and dimethylfumarate under the experimental conditions impedes the development of hypomelatoninemia, this was accompanied by a two-fold increase in the blood serum melatonin concentration compared to the control group. Moreover, the administration of ammonium pyrrolidine dithiocarbamate and dimethylfumarate significantly reduces the production of superoxide anion radical by electron transport chains of mitochondria (by 47.9 and 51.3%) and sarcoplasmic reticulum (by 48.6 and 52.0%) in the homogenate of femoral muscles, the total activity of NO synthase (by 37.2 and 36.2%) and its inducible isoform (by 41.1 and 40.0%), the concentration of peroxynitrites of alkaline and alkaline earth metals (by 37.2 and 41.0 %), while the activity of constitutive NO-synthases (by 2.9 and 2.8 times) and their conjugation index (by 5.2 and 5.4 times) increases compared to the respective control values. We suggest that modulators of redox-sensitive transcription factors NF-κB and Nrf2 under conditions of chronic hypomelatoninemia and the exposure to the carbohydrate-lipid diet are effective means to restrain the development of oxidative-nitrosative stress in skeletal muscles. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the effects of bioflavonoids, epigallocatechin-3-gallate (EGCG) and quercetin, on the production of reactive oxygen and nitrogen species in the liver of rats under round-the-clock light exposure with an intensity of 1500 lux for 30 days while being kept on carbohydrate-lipid diet (20% fructose solution and appropriate food) for 60 days. In the liver tissues, the rate of the superoxide anion production by NADPH-dependent electron transport chains (microsomal monooxygenases and constitutive uncoupled NO synthases) increased by 1.93 times, by the mitochondrial respiratory chain by 1.89 times, and it was doubled by leukocyte NADPH-oxidase. The total activity of NO synthase was increased by 2.35 times, the activity of its inducible isoform increased by 2.57 times, and the concentration of alkali and alkaline earth metals peroxynitrites elevated by 1.68 times. Administration of bioflavonoids-epigallocatechin-3-gallate and quercetinsignificantly restrained the rate of superoxide anion production in the liver tissues by microsomal monooxygenases and NO synthase by 39.1 and 40.1%, by the mitochondrial respiratory chain by 37.2 and 34.4%, by leukocyte NADPH-oxidase by 35.0 and 32.1%, respectively. Epigallocatechin-3-gallate and quercetin inhibited the total activity of NO-synthase by 46.7 and 36.2%, the activity of its inducible isoform by 49.6 and 39,0%, increased the activity of the constitutive isoenzyme NO-synthase by 2.9 times and its coupling index by 4.5 and 4.7 times. Additionally, administration of these bioflavonoids lowered the concentration of peroxynitrites of alkali and alkaline earth metals by 30.5 and 34.3% compared to the respective values obtained in the group of rats, which did not receive the bioflavonoids, but were exposed to light and carbohydrate-lipid-rich diet. We suggest that epigallocatechin-3-gallate and quercetin in the above experimental conditions are effective means to restrain the formation of reactive oxygen and nitrogen species in the liver tissue. [ABSTRACT FROM AUTHOR]

We studied the effect of hypomelatoninemia induced by round-the-clock light with an intensity of 1500 lx for 60 days on carbohydrate and lipid metabolism of white rats kept on high-calorie carbohydrate-lipid diet (HCCLD, 20% fructose solution and the diet). It was found that these conditions reduced the melatonin concentration in the blood serum by 55.6% compared with the results obtained from the animals exposed to the round-the clock light only. Herewith, the animals developed the insulin resistance syndrome, which was accompanied by more marked manifestations of its characteristic metabolic symptoms as hyperinsulinemia, dyslipoproteinemia, hypo-α-lipoproteinemia, hypertrialcylglycerolemia, and increased visceral fat mass. This condition demonstrated the development of decompensated lipid peroxidation and a decrease in the antioxidant potential in the blood of rats, but without significant changes in the concentration of systemic inflammation markers (tumor necrosis factor α and ceruloplasmin). Under these circumstances the formation of secondary peroxidation products (compounds reacting with thiobarbituric acid) surpassed the relevant results in the group exposed to the separate round-the-clock light and in the group kept on the high-calorie carbohydrate-lipid diet by 49.1% and 11.9% respectively. [ABSTRACT FROM AUTHOR]