The Role Of GLP-1 Receptor Agonist On Pancreas Islets β Cells In Rats With IGT

Objective Used animal experiments to compare the changes of the amount of pancreas isletsβcells and the function after GLP-1 receptor agonist(Exendin-4) interfered IGT rats. To investigateExendin-4 protect IGT rats pancreas isletsβcells and the effects to blood glucose and the otherbasic clinical characteristics.Methods 96 male Wistar rats in 4 ~ 5 weeks (150g ~ 180g) of clean grade were purchased inInstitute of Chinese Medicine of Shanxi. After one week adaptive feeding (five/cage), they weredivided into the Conventional feed group(n=24) and High sugar and fat diet fed group ( n=72)randomly. The Conventional feed group rats were fed by normal diet (13.4kJ/g, which accountedfor 10.2% of calories, fat and protein accounted for 23.3% respectively, carbohydrate accountedfor 66.5%); The High sugar and fat diet fed group rats were given high-sugar and high-fat feed(21.8kJ/g, which accounted for 56.0% of calories, fat and protein accounted for 7.0%respectively, carbohydrates accounted for 37.0%) and free access to water, at room temperaturecontrolled at 18 ~ 22°C, relative humidity 30% ~70%. Two groups of rats twice a day morningand evening feeding, daily food intake for each rat to vote for 3% of body weight. When 12weeks, do oral glucose tolerance test (OGTT): after fasting 12-14h, cut the tail blood and rapidblood glucose meters measure fasting blood glucose (FBG), intragastric administration with 50%glucose injection 2g/kg body weight, after 2h cut the tail blood again and measure 2hpostprandial blood glucose (2hPG). Building a successful model was 3.9mmol/L≤FBG<6.1mmol/L, 7.8mmol/L≤2hPG<11.1mmol/L and continued for more than a week. TheConventional feed group rats, blood glucose to normal,as the normal glucose tolerancegroup(NGT group, n=24) and continue to give regular feed and freedom drinking water. 62 ofThe High sugar and fat diet fed group rats were into models, and randomly divided into IGTgroup, Low-Exendin4 group,High-Exendin4 groups. To continue to give high-sugar high-fatfeeding and freedom drinking water.All the rats were divided into the 0-week group, 4-weekgroup, 8-week group when they became successful models. The normal glucose tolerance groupwas divided into Normal Control 0-week group (N0W group, n=8), Normal Control 4-weekgroup(N4W group, n=8), Normal Control 8-week group (N8Wgroup,n=8) randomly. Impairedglucose tolerance group was randomly divided into IGT 0-week group(IGT0W group, n=6),4-week group(IGT4W group, n=7), 8-week group (IGT8W group, n=7); Low-Exendin4-0 weekgroup(L-Ex0W group, n=7), Low-Exendin4-4 week group(L-Ex4W group, n=7), Low-Exendin4-8week group(L-Ex8W group, n=7); High-Exendin4-0 week group(H-Ex0W group, n=7),High-Exendin4-4 week group(H-Ex4W group, n=7), High -Exendin4-8 week group(H-Ex8W group,n=7). The Normal Control group and IGT group were given Exendin-4 twice a day(5ug/kg). The High-Exendin4 group were given GLP-1 receptor agonist Exendin-4 twice a day(10ug/kg). After 0 week, four weeks and eight weeks, 1 day before the end of the experiment,after fasting 12 ~ 14h, to measure the weight, FBG and PG2h. The next day, after fasting 12 ~14h anesthetized rats with 5% chloral hydrate by intraperitoneal injection 0.6ml/100g bodyweight, taken abdominal primary venous blood, rapid centrifugation of blood samples of serumspecimens from -70°C to save, the way of chemoluminesence under test insulin. Quickly removethe pancreas after taking the blood, washed with ice PBS. Fixed the pancreas tissues by 10%formalin,dehydrated, embedded in paraffin, regular slices, for HE staining, obverse the size andamout of pancreas islets. To measure the pancreas isletsβcells equal-volume saline twice a day.The Low-Exendin4 group were given GLP-1 receptor agonist PDX-1, BCL -XL, Caspase-3 byimmunohistochemisty.All measurement data using standard mean±deviation( x±s ), using Single factor analysis ofvariance, T test, SNK-q test analytic the results.Results1. The changes of weight between each group Low-Exendin4-0 week group compared withIGT 0 week group, the weight difference do not have statistically significant(P>0.05). Comparedwith the corresponding time period Normal Control group the weight is increasing(P<0.05).Low-Exendin4-4 Week group compared with 0 Week group,IGT 4 Week group, the weight isdecreasing(P<0.05). Compared with the corresponding time period Normal Control group theweight is increasing(P<0.05). Low-Exendin4-8Week group compared with 0 Week group, IGT 8Week group, the weight is decreasing(P<0.05). Compared with the corresponding time periodNormal Control group the weight is increasing(P<0.05). Low-Exendin4-8Week group comparedwith 4 Week group, the weight is decreasing(P<0.05). High-Exendin4-0 week group comparedwith the corresponding time period Low-Exendin4 group, the weight difference do not havestatistically significant(P>0.05). High-Exendin4-4 week group, 8 week group compared with thecorresponding time period Low-Exendin4 group, the weight is decreasing(P<0.05).2. The changes of blood glucose and insulin clinical index Low-Exendin4-0 week groupcompared with IGT 0 week group,the PG2h and insulin difference do not have statisticallysignificant(P>0.05). Compared with the corresponding time period Normal Control group thePG2h is increasing(P<0.05), blood insulin is decreasing(P<0.05). Low-Exendin4-4 Week groupcompared with 0 Week group, IGT 4 Week group, the PG2h is decreasing(P<0.05), blood insulin is increasing(P<0.05). Compared with the corresponding time period Normal Control group thePG2h is increasing(P>0.05), blood insulin is decreasing(P>0.05), difference do not havestatistically significant. Low-Exendin4-8Week group compared with 0 Week group, IGT 8 Weekgroup,the PG2h is decreasing(P<0.05), blood insulin is decreasing(P<0.05). Compared with thecorresponding time period Normal Control group the PG2h is increasing(P>0.05), blood insulinis decreasing(P>0.05), difference do not have statistically significant. Low-Exendin4-8Weekgroup compared with 4 Week group, the PG2h is decreasing(P>0.05), blood insulin isincreasing(P>0.05), difference do not have statistically significant. High-Exendin4-0 week groupcompared with the corresponding time period Low-Exendin4 group, the PG2h and blood insulindifference do not have statistically significant(P>0.05). High-Exendin4-4 week group, 8 weekgroup compared with the corresponding time period Low-Exendin4 group, the PG2h isdecreasing, blood insulin is increasing , difference do not have statistically significant(P>0.05).3. The changes of rats pancreas by HE dyeing under the light microscope Low-Exendin4-0week group compared with IGT 0 week group, the area of single pancreas islet and the amountof rats pancreas islets do not have difference obviously. Compared with the corresponding timeperiod Normal Control group the the area of single pancreas islet, the amount of rats pancreasislets is decreasing. Low-Exendin4-4 Week group compared with 0 Week group, IGT 4 Weekgroup, the the area of single pancreas islet, the amount of rats pancreas islets is increasing.Compared with the corresponding time period Normal Control group the amount of ratspancreas islets is decreasing. Low-Exendin4-8Week group compared with 0 Week group, IGT 8Week group, the area of single pancreas islet, the amount of rats pancreas islets is increasing.Compared with the corresponding time period Normal Control group, the area of single pancreasislet, the amount of rats pancreas islets, do not have difference obviously. Low-Exendin4– 8Week group compared with 4 Week group, the area of single pancreas islet, the amount of ratspancreas islets is increasing. High-Exendin4-0 week group compared with the correspondingtime period Low-Exendin4 group, the area of single pancreas islet, the amount of rats pancreasislets, do not have difference obviously. High-Exendin4-4 week group, 8 week group comparedwith the corresponding time period Low-Exendin4 group, the area of single pancreas islet, theamount of rats pancreas islets is increasing.4. The changes of rats pancreas expression of PDX-1 Low-Exendin4-0 week group comparedwith IGT 0 week group, the pancreas PDX-1 expression difference do not have statisticallysignificant(P>0.05). Compared with the corresponding time period Normal Control group,PDX-1 expression is decreasing(P<0.05). Low-Exendin4-4 Week group compared with 0 Week group, IGT 4 Week group, PDX-1 expression is increasing (P<0.05). Compared with thecorresponding time period Normal Control group PDX-1 expression is de creasing(P<0.05).Low-Exendin4-8Week group compared with 0 Week group,IGT 8 Week group, PDX-1expression is increasing (P<0.05). Compared with the corresponding time period Normal Controlgroup, PDX-1 expression is decreasing, difference do not have statistically significant(P>0.05).Low-Exendin4-8Week group compared with 4 Week group, PDX-1expression is increasing(P<0.05). High-Exendin4-0 week group compared with the corresponding time periodLow-Exendin4 group, PDX-1 expression difference do not have statistically significant(P>0.05).High-Exendin4-4 week group, 8 week group compared with the corresponding time periodLow-Exendin4 group, PDX-1 expression is increasing (P<0.05).5. The changes of rats pancreas expression of BCL-XL Low-Exendin4-0 week groupcompared with IGT 0 week group, the pancreas BCL-XL expression difference do not havestatistically significant(P>0.05). Compared with the corresponding time period Normal Controlgroup,BCL-XL expression is decreasing(P<0.05). Low-Exendin4-4 Week group compared with0 Week group, IGT 4 Week group, BCL-XL expression is increasing (P<0.05). Compared withthe corresponding time period Normal Control group BCL-XL expression is decreasing (P<0.05).Low-Exendin4-8Week group compared with 0 Week group, IGT 8 Week group, BCL-XLexpression is increasing (P<0.05). Compared with the corresponding time period Normal Controlgroup, BCL-XL expression is decreasing, difference do not have statistically significant(P>0.05).Low-Exendin4-8Week group compared with 4 Week group, BCL-XL expression is increasing(P<0.05). High-Exendin4-0 week group compared with the corresponding time periodLow-Exendin4 group, BCL-XL expression difference do not have statistically significant(P>0.05). High-Exendin4-4 week group,8 week group compared with the corresponding timeperiod Low-Exendin4 group, BCL-XL expression is increasing (P<0.05).6. The changes of rats pancreas expression of Caspase-3 Low-Exendin4-0 week groupcompared with IGT 0 week group, the pancreas Caspase-3 expression difference do not havestatistically significant(P>0.05). Compared with the corresponding time period Normal Controlgroup, Caspase-3 expression is increasing(P<0.05). Low-Exendin4-4 Week group compared with0 Week group, IGT 4 Week group, Caspase-3 expression is decreasing(P<0.05). Compared withthe corresponding time period Normal Control group Caspase-3 expression is increasing(P<0.05).Low-Exendin4-8Week group compared with 0 Week group,IGT 8 Week group, Caspase-3expression is decreasing(P<0.05). Compared with the corresponding time period Normal Controlgroup, Caspase-3 expression is increasing(P<0.05), difference do not have statistically significant(P>0.05). Low-Exendin4-8Week group compared with 4 Week group, Caspase-3expression is decreasing(P<0.05). High-Exendin4-0 week group compared with thecorresponding time period Low-Exendin4 group, Caspase-3 expression difference do not havestatistically significant(P>0.05). High-Exendin4-4 week group, 8 week group compared withthe corresponding time period Low-Exendin4 group, Caspase-3 expression is decreasing(P<0.05).ConclusioConclusions1. In the stage of impaired glucose tolerance, a series of characteristics have occurrenced whichinclued decrease the proliferation, increase the apoptosis, decrease the amounts ofβcells, theexpression of pancreasβcells PDX-1,BCL-XL decrease, the expression of pancreasβcellsCaspase-3 increase.2. GLP-1 receptor agonist increases the expression ofβcells PDX-1, BCL-XL, decreasesCaspase-3, advance IGT rats pancreas isletsβcells proliferation, decreases the apoptosis of ratspancreas isletsβcells with IGT, increase the amount of pancreas isletsβcells.3. The effects of GLP-1 receptor agonist on pancreas isletsβcells is increasing when prolongedthe treatment and increase the does in the certain scope.