Association of glucose homeostasis measures with heart rate variability (HRV) among hyperlipidemic rat model: protective role of Emblica officinalis

Abstract

Background: Altered glucose homeostasis due to hyperlipidemia mainly revolves around pathophysiological effects of abnormal lipid levels and insulin resistance. Reduced HRV an indicator of cardiac autonomic function is connected with greater risk of cardiovascular diseases. Glucose homeostasis markers were related with reduced cardiac autonomic functions in diabetic rats but results reported were discordant with those without diabetes. Aims and objectives: Study aimed to assess relation between glucose homeostasis with HRV among hyperlipidemic rats and to assess protective glucose regulatory actions of Emblica officinalis on hyperlipidemic rats. Material and Methods: Ethanolic extract of Emblica Officinalis (EEO) was prepared. Rats were divided into four groups (n=6); group 1- Control (20% fat); group 2 (20% fat+ EEO 100 mg/kg/b w); group 3 (30% fat) and group 4 (30% fat + EEO 100 mg/kg/b w) for 21 days.Gravimetry and electrophysiological analysis (HRV and sympathovagal balance) were done. In vivo, tests on glucose regulatory system were conducted like fasting and postprandial glucose, fasting insulin levels and Oral Glucose Tolerance Test. Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) was calculated. ANOVA and Pearson's correlation was done to analyze the data. Results: Subchronic supplementation of EEO to hyperlipidemic rats showed a significant beneficial effect on altered glucose homeostasis. An electrophysiological evaluation revealed altered sympathovagal balance in hyperlipidemic rats which indicate cardiac autonomic malfunctions and found to be improved in EEO supplemented rats. A significant correlation was observed between HRV and glucose homeostasis. Conclusion: Impairment in glucose homeostasis due to High-fat diet is associated with altered heart rate variability. EEO supplementation found to be protective against high-fat diet-induced cardiac autonomic dysfunction and glucose metabolism.