EFFECT OF MELATONIN AND QUERCETIN ON INFLAMMATION AND METABOLISM UNDER CONDITIONS OF ROUND-THECLOCK LIGHTING AND HIGH-CALORIE CARBOHYDRATE-LIPID DIET

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.