Effects of graviola oil extract on adipokine, cerebral, cardiac and intestinal response and some biochemical parameters in rats with experimental type 2 diabetes

Diabetes mellitus (DM) is a metabolic disease with an increasing prevalence worldwide, characterized by chronic hyperglycemia, resulting from absolute or relative insufficiency of insulin secretion by the pancreas, insulin ineffectiveness or structural defects in the insulin molecule, causing disorders in carbohydrate, fat and protein metabolism. The aim of this study was to investigate the effects of STZ and different rates of graviola oil extract in experimental Type 2 diabetic rats on adipokine, cardiac response, intestinal and mitochondrial functions and their relationship with some biochemical parameters. For this purpose, 64 adult male Wistar albino rats, aged between 8-10 weeks and weighing 195-215 g, were used. Before the experiment, the rats were randomly selected with equal average body weights and 8 rats in each group and were formed into 8 groups as Control (K), G100, G200, G300; Diabetes Control (DK), DG100, DG200, DG300. In the control (C) group, only 0.5 ml of physiological serum was injected intraperitoneally (i.p) to the rats to create a healthy control group. In order to experimentally induce diabetes, a single dose of 50 mg/kg of freshly prepared STZ solution in 0.9% physiological serum was administered to the rats in the DK and DR100, DR200, and DR300 groups via i.p. 0.5 ml. Glucose was measured in blood samples taken from the tail vein for fasting blood sugar measurements 72 hours after the injection. Rats with a blood serum glucose level of 250 mg/dl or above were accepted as having Type 2 diabetes. In order to establish the same standard as the other groups, physiological serum (SF) was administered to the animals in the K and DK groups via i.p. throughout the experimental period. Graviola oil extract was administered orally to the G100, G200 and G300 groups and the DG100, DG200 and DG300 groups at doses of 100, 200 and 300 mg/kg for 21 days. The rats were fed daily with drinking water and standard rat chow ad libitum in polypropylene cages under optimum laboratory conditions (22°C, 12 hours of dark/light) throughout the experiment. Blood samples were taken from the tail vein (vena caudalis) of all subjects on days 0 and 21 of the study. In the serum samples taken, apelin, asprosin, irisin, Brain-Derived Neurotrophic Factor (BDNF), Cardiac Troponin I (cTnI), Glucagon-Like Peptide-1 (GLP-1) levels were measured by ELISA method, and biochemical parameters were evaluated by fully automatic biochemistry device Cobas 8000 (Roche, Germany). While the live weight change of the rats in the study groups decreased in the STZ group compared to the control group, there was a significant increase in the G300 and DG300 groups compared to the DK group (p < 0.01). According to the results obtained, the mean serum irisin, BDNF, LDL (Low-density lipoprotein), AST (Aspartate Aminotransferase), ALP (Alkaline Phosphatase), ALT (Alanine Aminotransferase), insulin levels were determined to be at the lowest level on days 0 and 21 of the study in the DK group, respectively, while they were determined to be at the lowest level in the DR300 group due to the GOE (graviola oil extract) dose increase (p<0.01). On the other hand, mean serum asprosin, VLDL and glucose levels were highest in DK levels, while a decrease was detected in DG 300 groups due to GOE dose increase (p<0.01). As a result, it was concluded that 300 mg/kg graviola oil extract application in rats did not have any negative effect and could be useful in improving insulin resistance in impaired glucose metabolism in diabetes, but more comprehensive research would be necessary and beneficial.