ABSTRACT
Objective:To observe the effect of astragalus polysaccharide (APS) on taste receptor 1 member 2 (T1R2)/taste receptor 1 member 3 (T1R3) sweet taste receptor pathway in intestine of rat model induced by high-sugar and high-fat diet. Method:SD rats were randomly divided into normal group, high-sugar and high-fat group and astragalus polysaccharide group. Rats in high-sugar and high-fat group and astragalus polysaccharide groups were fed with high-sugar and high-fat diet for 16 weeks, while rats in astragalus polysaccharide group were fed with APS (0.7 g·kg-1, per day) for 8 weeks during this period. Serum samples were collected to determine the levels of fasting blood glucose, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). Intestinum tenue was collected to determine mRNA expressions of T1R2/T1R3, α-gustducin (Gα gust), transient receptor potential cation channel subfamily member 5 (TRPM5) and proglucagon (PG) gene by Real-time PCR, and protein expressions of T1R2, Gα gust and glucagon-like peptide-1 (GLP-1) protein by Western blot. Result:Rats in high-sugar and high-fat group had significantly higher levels of TC, TG and LDL-C, and lower HDL-C level in serum than those in normal group (Pα gust and PG genes in intestine, were significantly down-regulated in high-sugar and high-fat group (PPα gust, TRPM5 and PG genes in intestine were significantly up-regulated in astragalus polysaccharide group (Pα gust and GLP-1 protein expressions was consistent with that of T1R2, Gα gust and GLP-1 mRNA expressions. Protein expressions of T1R2, Gα gust and GLP-1 and mRNA expression of T1R3 were significantly lower in astragalus polysaccharide group than those of control group (PConclusion:APS could improve disturbance of lipid metabolism and impairment of intestinal sweet taste receptor pathway for rat model induced by high-sugar and high-fat diet.
ABSTRACT
Objective To investigate the effect of duodenal-jejunal bypass(DJB) on glucose metabolism and the expression of ileum proglucagon mRNA in Goto-Kakizaki (GK) type 2 diabetic rats.Methods 18 male GK rats and 1 8 male Wistar rats were randomly divided into 4 groups:GK operation group(group A),GK sham operation group(group B),Wistar operation group (group C),Wistar sham operation group (group D).There were 9 rats in each group.The fasting blood glucose and GLP-1 levels were measured before and at the 8th weekafter surgery.Oral glucose tolerance test was measured,and the area under blood glucose concentration curve wascalculated.Ileum tissues were obtained 8 weeks postoperatively and reverse transcriptase polymerase chain reac-tion was used to detect ileum PG mRNA expression after the operation.Results At the 8th week after surgery,the fasting blood glucose of group A decreased from(8.73 ± 1.30) mmol/L to(5.86 ±0.57) mmol/L(P ＜0.05).Area under blood glucose concentration curve decreased from preoperative(60.23 ± 5.14)mmol · h/L to (47.80 ±1.79) mmol· h/L(P ＜ 0.05).Fasting serum GLP-1 in group A increased from (7.69 ± 0.74) pmol/L to (29.00 ±4.85) pmol/L while postprandial GLP-1 increased from(15.74 ± 5.71) pmol/L to (45.78 ± 7.26) pmol/L (P ＜0.05).At the 8th week after surgery,the ileum PG mRNA level in group A was significantly higher than that in group B(P ＜ 0.05).Conclusions DJB can directly improve glucose metabolism in non-obese type 2 diabetic rats,and the operation has no hypoglycemic effect on normal blood glucose.The increased expression of ileum PG mRNA might contribute to the hypoglycemic effect of the surgery.