Tracking changes of the parameters of glucose-insulin homeostasis during the course of obesity in B6D2F1 mice

Extra virgin coconut oil (Cocos nucifera L.) intake shows neurobehavioural and intestinal health effects in obesity-induced rats

The present study aimed to evaluate the effect of E-VCO on the neurobehaviour and intestinal health parameters of obesity-induced rats, focusing on food consumption, body composition, bacterial and faecal organic acids and histological analyses in the hippocampus and colon. A total of 32 male Wistar rats were randomized into healthy (HG, n = 16) and obese groups (OG, n = 16), which consumed a control or cafeteria diet for eight weeks, respectively. After this period, they were subdivided into four groups: healthy (HG, n = 8); healthy treated with E-VCO (HGCO, n = 8); obese (OG, n = 8); obese treated with E-VCO (OGCO, n = 8), continuing for another eight weeks with their respective diets. The treated groups received 3000 mg kg^-1 of E-VCO and control groups received water via gavage. Food preference, body weight gain, body composition, anxiety- and depression-like behaviour were evaluated. Bacteria and organic acids were evaluated in faeces, and histological analyses of the hippocampus and M1 and M2 macrophages in the colon were performed. E-VCO reduced energy intake (16.68%) and body weight gain (16%), although it did not reduce the fat mass of obese rats. E-VCO showed an antidepressant effect, increased lactic acid bacteria counts and modulated organic acids in obese rats. Furthermore, E-VCO protected the hippocampus from neuronal degeneration caused by the obesogenic diet, decreased the M1 macrophage and increased the M2 macrophage population in the gut. The results suggest neurobehavioural modulation and improved gut health by E-VCO, with promising effects against obesity-related comorbidities.

Study of blood glucose and insulin infusion rate in real-time in diabetic rats using an artificial pancreas system

Artificial pancreas system (APS) is an emerging new treatment for type 1 diabetes mellitus. The aim of this study was to develop a rat APS as a research tool and demonstrate its application. We established a rat APS using Medtronic Minimed Pump 722, Medtronic Enlite sensor, and the open artificial pancreas system as a controller. We tested different dilutions of Humalog (100 units/ml) in saline ranged from 1:3 to 1:20 and determined that 1:7 dilution works well for rats with ~500g bodyweight. Blood glucose levels (BGL) of diabetic rats fed with chow diet (58% carbohydrate) whose BGL was managed by the closed-loop APS for the total duration of 207h were in euglycemic range (70-180 mg/dl) for 94.5% of the time with 2.1% and 3.4% for hyperglycemia (>180mg/dl) and hypoglycemia (<70 mg/dl), respectively. Diabetic rats fed with Sucrose pellets (94.8% carbohydrate) for the experimental duration of 175h were in euglycemic range for 61% of the time with 35% and 4% for hyperglycemia and hypoglycemia, respectively. Heathy rats fed with chow diet showed almost a straight line of BGL ~ 95 mg/dl (average 94.8 mg/dl) during the entire experimental period (281h), which was minimally altered by food intake. In the healthy rats, feeding sucrose pellets caused greater range of BGL in high and low levels but still within euglycemic range (99.9%). Next, to study how healthy and diabetic rats handle supra-physiological concentrations of glucose, we intraperitoneally injected various amounts of 50% dextrose (2, 3, 4g/kg) and monitored BGL. Duration of hyperglycemia after injection of 50% dextrose at all three different concentrations was significantly greater for healthy rats than diabetic rats, suggesting that insulin infusion by APS was superior in reducing BGL as compared to natural insulin released from pancreatic β-cells. Ex vivo studies showed that islets isolated from diabetic rats were almost completely devoid of pancreatic β-cells but with intact α-cells as expected. Lipid droplet deposition in the liver of diabetic rats was significantly lower with higher levels of triacylglyceride in the blood as compared to those of healthy rats, suggesting lipid metabolism was altered in diabetic rats. However, glycogen storage in the liver determined by Periodic acid-Schiff staining was not altered in diabetic rats as compared to healthy rats. A rat APS may be used as a powerful tool not only to study alterations of glucose and insulin homeostasis in real-time caused by diet, exercise, hormones, or antidiabetic agents, but also to test mathematical and engineering models of blood glucose prediction or new algorithms for closed-loop APS.