Research On Hypoglycemic Effect Of Oat Products And Its Mechanism

The paper studied the effect of oatβ-gluca n, oat bran, oat flour and rolled oat on glucosemetabolism of experimental typeⅡdiabetic mice. The objective was to be sure of theoptima l hypoglycemic dose of oatβ-gluca n; mea nwhile, to study the hypoglycemic effect ofthe oat bran, oat flour and rolled oat and discuss the possibly hypoglycemic mecha nism.The vivo of experimental typeⅡdiabetic mice and the vitro of cell culture were to besure of the optima l hypoglycemic dose of oatβ-gluca n. The experimental typeⅡdiabeticmice induced with high-sucrose and high-fat diet combinating with streptozotocin injectionwere randomly alloca ted into 5 groups: model control group (physiologica l saline), positivecontrol group (1% metformin solution) as well as high-dose (2000mg/kg·bw), midd le-dose(1000mg/kg·bw) and low-dose (500mg/kg·bw) of oatβ-gluca n. There are 15 mice in eachgroup. We set the nega tive control mice (physiologica l saline) which fed with the norma l diet.Each treatment lasted for 6 weeks during which period the diabetic mice were given highsucroseand high-fat diet besides the oral administration once a day. The food intake wasrecorded every week. Body weight, fasting blood glucose and glycosylated serum proteinwere evaluated every 2 weeks and the blood samples were collected from the tail vein ofmice. At the seventh week, mice of each group were determined the blood glucose values atthe 0, 30, 60 and 120min as well as the insulin concentration, respectively. At the same time,mouse insulinoma cell lineβTC-6 were cultured in vitro, treating with oatβ-gluca n (30, 70,130, 160 and 200mg/ml), then theβTC-6 cells'proliferation and glucose stimula ted insulinsecretion were measured. The results showed that the high dose of oatβ-gluca n reduced thefood intake, fasting blood glucose and glycosylated serum protein (p<0.01), improved weightloss, insulin secretion and glucose tolera nce (p<0.01). Moreover, the hypoglycemic effect ofhigh-dose oatβ-gluca n versus metformin (p>0.05); the vitro experiment indica ted oatβ-gluca n could activate the proliferation and insulin secretion of B cells, and there was asignica nt associa tion between dose and effect.To investigate the hypoglycemic effect and mecha nism of oat bran, oat flour and rolledoat, we established the model of experimental typeⅡdiabetic mice as above, and they werealso randomly divided into 5 groups: model control group, positive control group (1%metformin solution), oat bran group (4% oat bran), oat flour group (17% oat flour) and rolled oat group (7.39% rolled oat). Oat products and metformin added into the high-sucrose andhigh-fat diet with the proportion above on the basis of the optima l-dose oatβ-gluca n.Similarly, the food intake and body weight were recorded; blood glucose , glycosylated serumprotein as well as the insulin concentration, respectively were evaluated. At the end of theexperiment, each group was fasted for 12h. Blood was collected from ocular puncture intoplastic centrifuge tube and to be determined the concentrations of gluca gon-like pepfide-1(GLP-1), peroxisome proliferator's activator receptorsγ(PPARγ), free fatty acid (FFA) andsuccinate dehydrogenase (SDH). Then mice were anesthetized and sacrificed by decapitation.Immed iately, the liver, kidney and pancreas were dissected out and fixed in 10% neutralbuffered formalin for histopa thologica l examina tion. Liver and heart after excision from theanima l were used to estimate the glycogen contents of liver and muscle. It could be foundthrough comparison that oat bran could significa ntly improve the growth status of diabeticmice (p<0.01), decreased the fasting blood glucose and glycosylated serum protein (p<0.01),improve the glucose tolera nce and insulin secretion (p<0.01), and the the hypoglycemic effectwas not more tha n metformin (p>0.05). Besides, compared with model control group after 6-week treatment of oat products, the glycogen content, GLP-1 and PPARγconcentrations ofoat product-fed diabetic mice increased (p<0.05), FFA content and SDH activity decline d(p<0.05); the histopa thologica l structure of liver, kidney and pancreas as well as the apoptosisof pancreatic cell both improve d (p<0.05).Vivo combined with the vitro experiment both indica ted the optima l dose of oatβ-gluca non hypoglycemic activity was 2000mg/kg·bw. Oat products had a hypoglycemic effect andthe oat bran was the best. Oat products regulated the glucose and fat metabolism, stimula tedthe secretion of insulin and incretin hormone, activated the nuclear receptor and protected thenorma l physiologica l function of ma in organs which would be associa tion with thehypoglycemic effect.