RESUMEN
Objective: To evaluate the hypoglycemic effect of aqueous extract from Taraxaci Herba (AETH) on postprandial blood glucose (PBG) in diabetic rats induced by Streptozotocin (STZ) and to explore the mechanism. Methods: The PBG within 120 min was measured after 7 d ig administration of AETH (400, 200, and 100 mg/kg) in normal rats and diabetic model rats induced by STZ, and ELISA was performed to detect the serum insulin of rats in each group. The euglycemic clamp assay was performed to investigate the effect of AETH (400 mg/kg) on the insulin sensitivity in normal rats, and the glucose infusion rate (GIR) was detected. The 50% inhibiting concentration (IC50) against α-glucosidase was measured in vitro, using pNPG as substrate. Caco-2 cells were preincubated for 72 h with AETH (200 and 100 mg/L), and then the capacities of Caco-2 monolayer on maltose hydrolysis and glucose absorption were measured. Results: The 7 d ig administration of AETH decreased the PBG significantly in diabetic rats induced by STZ, but had no effect on serum insulin level and GIR. AETH inhibited α-glucosidase in vitro, and the IC50 was higher than that of acarbose. AETH (200 mg/L) inhibited the capacities of Caco-2 monolayer on both maltose hydrolysis and glucose absorption. Conclusion: AETH has the hypoglycemic effect on PBG in diabetic rats, and the mechanism is related to the inhibition of maltose hydrolysis and glucose absorption in small bowel.
RESUMEN
To investigate the effect of electro-acupuncture stimulation (EAS) on insulin sensitivity in rats, we performed several stimulations on Otsuka Long Evans Tokushima Fatty (OLETF) rats, during euglycemic clamp. We divided OLETF rats into five groups according to the kind of the stimulation: EAS at vagal innervated region of the auricle (AVA), EAS at non-vagal innervated region of the auricle (ANVA), EAS on the back of the body (AB), pinching on the back of the body (PB), and no stimulation on the body (NS). These procedures were also applied on Long Evans Tokushima Otsuka (LETO) rats as a control study.<br>Furthermore, we performed long-term stimulation (from six to 24 weeks of age) on OLETF rats to assess the preventive effect of those stimulations on the formation of the insulin resistance. EAS of pulse duration 300ms, 1.5V, 1Hz was applied for 10 or 15minutes. As a result, the glucose infusion rate (GIR) showed significantly higher levels during stimulation of PB group in LETO rats. On the other hand, the GIR of AVA group in LETO rats and PB group in OLETF rats were decreased by stimulation. The GIR in AVA group and AB group after long-term stimulation were significantly higher than those of NS group in OLETF rats. These results suggested that EAS at the auricle and the back is useful for the prevention of the formation of insulin resistance when it's applied before onset of the symptoms in OLETF rats.