Effects of Ilex Guayusa Tea on Glycaemia, Cardiovascular Autonomic Modulation and Oxidative Stress in Streptozotocin‐Diabetic Rats

다국어 초록 (Multilingual Abstract)

The incidence of cardiovascular diseases (CVD) increases significantly worldwide. Furthermore, it is the main cause of morbidity and mortality among diabetic patients. Rats induced to diabetes by streptozotocin (STZ) and untreated with insulin have similar alterations seen in humans, such as hyperglycemia, polydipsia, polyuria and weight loss, as well as cardiomyopathy, diabetic neuropathy and increased oxidative stress. Thus, the aim of this study was to verify the effects of ilex guayusa tea consumption on cardiovascular, autonomic, metabolic and oxidative stress alterations of an experimental model of diabetes. Thirteen Wistar rats were divided into two groups: Diabetic (D; n=7) and Diabetic + Ilex Guayusa (DG; n=6). Diabetes was induced by a single injection of STZ (50 mg/kg, iv.). Guayusa tea was administered for 21 days (3.0 g/L). Arterial pressure (AP) was directly measured. Oxidative stress was measured on heart and brain. At the beginning of the protocol glycaemia was similar between the groups (D: 330±32 vs. DG: 332±20 mg/dL). However, throughout the protocol, the D group showed a raise of glycaemia, evidenced by a greater area under the curve (AUC) (D: 1222±43 vs. DG: 1049±59 mg/dL*3 weeks). Indeed, increased glycaemia was associated with an increased oxidative profile. Positive correlations were observed between AUC of glycaemia and lipoperoxidation in the brain (r: 0.58; p: 0.04) and damage to protein in the heart (r: 67; p: 0.01). No differences in AP, heart rate and heart rate variability were observed between groups. However, regarding vascular sympathetic modulation, the D group had a reduction in LF‐SAP (1.3±0.3 vs. DG: 3.5±0.8 mmHg2) and VAR‐SAP (8.0±1.7 vs. DG: 15.0±1.7 mmHg2). This reduction in vascular sympathetic modulation, which in this model is considered a poor prognosis, was negatively correlated with AUC of glycaemia (AUC of glycaemia and VAR‐SAP, r: −0.57, p: 0.04). The results suggest a beneficial potential of guayusa tea consumption on metabolic, autonomic and oxidative stress in this model of diabetes.
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Universidade Nove de Julho
This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.