EPIGALLOCATECHIN-3-GALLATE ALLEVIATES METABOLIC DISORDERS IN RATS SIMULTANEOUSLY EXPOSED TO ROUND-THE-CLOCK LIGHTING AND KEPT ON HIGH-CALORIE CARBOHYDRATE-LIPID DIET

Abstract

The aim of the study is to investigate the effect of epigallocatechin-3-gallate (EGCG) on the parameters of carbohydrate and lipid metabolism in the blood serum of rats exposed to round-the-clock lighting (RCL) and kept on high-calorie carbohydrate-lipid diet (HCCLD). The experiments were performed on 21 white Wistar rats weighing 210-250 g, divided into 3 groups. Animals in the first group (control) received a standard diet (energy value 2720 kcal/kg) and were exposed to an equally altered light and darkness periods. The rats of the second and third groups were under the constant round-the-clock light exposure and received HCCLD (4477 kcal/kg). In addition to the conditions in the second group, the test animals of the third group were administered EGCG daily through intragastric gavage in a dose of 40 mg/kg. An enzyme-linked immunosorbent assay kit for rat serum was used to assess insulin concentration. The concentration of serum glucose, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), and triacylglycerols (TAG) was determined by enzymatic methods using photometric equipment. Insulin resistance was assessed by the HOMA-IR (Homeostatic Model Assessment) index. With the administration of EGCG, the concentration of glucose and insulin in the blood serum decreased by 34.7% and 59.1%, respectively, compared to group 2, and the HOMA-IR was 61.5% lower than in the comparison group. The HDL content increased with the administration of EGCG in the experiment and was 91.3% higher compared to the findings in the group 2. Under these circumstances, the concentrations of VLDL and TAG in the blood serum were significantly lower by 37.5 and 37.1% than the respective values in the group 2. It can be suggested that the administration of the bioflavonoid epigallocatechin-3-gallate significantly alleviates metabolic disorders in rats simultaneously exposed to RCL and kept on HCCLD.