苦瓜多糖降血糖活性成分的研究

目的研究苦瓜多糖最佳降糖活性成分的降血糖功能及其机制。方法比较苦瓜水提多糖和苦瓜碱提多糖对链脲霉素(STZ)诱导的糖尿病小鼠的降糖效果,初步分析其降糖机制。结果苦瓜碱提多糖200和400mg/kgbw都可显著降低STZ糖尿病小鼠的血糖葡萄糖耐量及肝糖原的含量,果糖胺的含量同样也有所降低。分子量最大的苦瓜碱提多糖降糖活性最好。结论大分子量苦瓜多糖的降糖效果较好,其机制可能是通过减弱STZ对胰岛β细胞的损伤或改善受损β细胞的功能,从而起到调节血糖的作用。     

南瓜提取物对糖尿病大鼠降糖效果研究

目的 :　研究南瓜多糖 (A)、南瓜种子发芽后分子量大于 60 ku的蛋白组分 (B)、分子量 3～ 60 ku的蛋白组分 (C)、分子量小于 3 ku的蛋白组分 (D)、精氨酸 (E)和南瓜籽油 (F)对糖尿病大鼠的降血糖作用。方法 :　雄性大鼠 1 60只 ,随机抽取 1 0只作空白对照 ,余下 1 5 0只 ,禁食后于次日晨腹腔注射四氧嘧啶 1 70 mg/kg,72 h后禁食 ,眼眶取血 ,测定血糖值。取血糖值在 7.2 8mmol/L以上者随机分层分组 ,共 1 5组 :模型组、A大小剂量组 (1 0 0 0、5 0 0 mg/kg)、B大小剂量组(3 0 0、1 5 0 mg/kg)、C大小剂量组 (3 0 0、1 5 0 mg/kg)、D大小剂量组 (3 0 0、 1 5 0 mg/kg)、E大小剂量组 (1 0 0、5 0 mg/kg)、F大小剂量组 (3 0 0、1 5 0 mg/kg)、优降糖 (2 0 mg/kg)。连续灌胃给药 1 0 d后 ,禁食 ,次日晨眼眶取血 ,测定血糖及胰岛素含量。随后灌胃给予葡萄糖 2 .5 g/kg,并测定糖耐量值。结果 :　南瓜多糖、分子量大于 60 ku和分子量小于 3 ku的蛋白组分 ,可以显著提高糖尿病大鼠胰岛素水平 ;南瓜籽油、3～ 60 ku的蛋白质组分和精氨酸可以改善糖尿病大鼠的糖耐量。结论 :　 3～ 60 ku的蛋白质组分的降血糖效果最佳 ,不但可以显著降低糖尿病大鼠空腹血糖值 ,而且可以改善各时段的糖耐量     

仙人掌、芦荟与苦瓜等降低糖尿病模型小鼠血糖的效果观察

为了观察仙人掌、芦荟及苦瓜等天然植物和不同膳食因素降低糖尿病小鼠血糖的效果 ,给小鼠腹腔注射链脲佐菌素 (STZ) 80mg kgBW以建立无症状糖尿病小鼠模型。分别采用 2种不同膳食配方及以仙人掌、芦荟、苦瓜汁灌胃 2 1天 ,检测其空腹 12h血糖和用 5 0 %葡萄糖 2 0ml kgBW灌胃 2h后血糖值。结果显示腹腔注射STZ 80mg kgBW 11天后 ,与对照组和注射STZ前比较各组小鼠空腹血糖均显著升高 (P <0 0 1) ,未出现摄食量、饮水量显著增加和体重下降的糖尿病典型症状 ,符合本实验要求的无症状期糖尿病模型小鼠。给予不同受试物 2 1天后 ,仙人掌、芦荟、苦瓜和膳食A组小鼠空腹血糖值均较STZ模型组显著降低 (P<0 0 1) ,同时也低于给受试物前水平 ,但未能达到正常组小鼠的血糖水平。当给予 5 0 %葡萄糖灌胃后 2h ,仙人掌、芦荟、苦瓜和膳食A组小鼠血糖值不同程度的低于STZ模型组 ,但仍高于正常组 (P <0 0 5 )。结果提示 ,仙人掌、芦荟、苦瓜和膳食A能不同程度降低无症状期糖尿病小鼠的空腹血糖和餐后 2h血糖。     

L-阿拉伯糖对2型糖尿病大鼠糖脂代谢的影响

目的探讨L-阿拉伯糖对2型糖尿病模型大鼠血糖、血脂、脏器及胰岛的影响。方法采用雄性Wistar大鼠高糖高脂饲料喂养8周后,按25mg/kgbw的剂量一次性腹腔注射链脲佐菌素建立2型糖尿病动物模型,按L-阿拉伯糖低剂量(50mg/kgbw)、中剂量(150mg/kgbw)及高剂量(500mg/kgbw)进行灌胃,以阿卡波糖(20mg/kgbw)作为阳性对照,所用L-阿拉伯糖及阿卡波糖均配制于糊精(0.36g/ml)与蔗糖(0.04g/ml)的悬浮液中,自由进食进水。给药4周后进行口服葡萄糖耐量试验,处死后对大鼠肝脏、附睾脂肪及盲肠进行称重,腹主动脉取血测定TC、TG、血糖及胰岛素水平,通过免疫组织化学切片对胰岛β细胞损伤程度进行评价。结果与模型组对比,低、中、高剂量的L-阿拉伯糖干预对糖尿病大鼠的血糖应答产生了显著影响,30、60和120min血糖值及AUC均显著低于模型对照组(P<0.05),其中以中剂量效果最为显著(P<0.01)。L-阿拉伯糖的干预对糖尿病大鼠胰岛素敏感性的改善未见显著,但增加了盲肠重量,对胰岛β细胞也呈现出保护作用。本研究中L-阿拉伯糖的干预对于血脂和血胆固醇的影响较小。结论 L-阿拉伯糖的中长期干预能够改善2型糖尿病大鼠的糖耐量,这种作用可能与L-阿拉伯糖对食物消化酶的抑制及对胰岛β细胞的保护作用相关。     

石花菜多糖对糖尿病大鼠降血糖作用的实验研究

目的研究石花菜多糖的降血糖作用。方法建立大鼠四氧嘧啶糖尿病模型,筛选50只血糖>16.1mmol/L的大鼠随机分为5组:石花菜多糖高剂量组(2 400mg/kg)、中剂量组(1 200mg/kg)、低剂量组(600mg/kg),格列吡嗪治疗组(1.8mg/kg),模型对照组。观察不同剂量的石花菜多糖对血糖、血清胰岛素和胰高血糖素的影响。结果石花菜多糖高剂量组、中剂量组可降低四氧嘧啶糖尿病大鼠的血糖,与模型对照组比较差异均有统计学意义(P<0.05或P<0.01)。高剂量组能提高胰岛素水平,降低胰高血糖素浓度,与模型对照组比较差异均有统计学意义(P<0.01)。结论石花菜多糖对糖尿病大鼠有降血糖作用。     

桑叶水提物与醇提物对糖尿病小鼠的协同降血糖效应

目的探讨桑叶水提物、醇提物单独及联合对糖尿病小鼠的降血糖作用。方法将桑叶水提物(800 mg/kg)、桑叶醇提物(500 mg/kg)、桑叶水提物+醇提物(低剂量150 mg/kg、高剂量300 mg/kg)及阳性对照二甲双胍(227.5 mg/kg)分别灌胃链脲佐菌素(STZ)诱导的糖尿病小鼠,每天一次,4周后处死小鼠,测定血糖、血清胰岛素水平、血清抗氧化酶活性,并观察肝脏、胰腺组织病理变化。结果与模型组相比,桑叶提取物各组均具有一定的降低血糖及血清胰岛素作用,并提高抗氧化酶活性,修复肝组织及胰岛细胞。桑叶水提物与醇提物以高剂量协同作用的效果最明显,该组血糖、血清胰岛素、胰岛素抵抗指数及敏感指数分别是模型组的61.0%、64.1%、42.9%及1.18倍(P0.05),且与二甲双胍对照组无明显差异(P0.05);该组抗氧化酶活性不仅高于模型组,而且高于二甲双胍对照组(P0.05)。结论桑叶水提物与醇提物可能通过提高糖尿病小鼠体内抗氧化酶活性,修复胰岛与肝脏氧化损伤,改善胰岛素效应细胞的抵抗效应,达到协同降血糖作用。     

链脲佐菌素注射剂量对建立2型糖尿病大鼠模型的影响

目的探讨不同链脲佐菌素(STZ)注射剂量和方法对大鼠血糖值、血糖稳定性和胰岛损害的影响。方法75只SPF级6周龄雄性Wistar大鼠高脂高糖、饲养8周后,分别给予20、25、30mg/kg的STZ腹腔注射。造模后连续7周每周观察各组大鼠的体重、空腹血糖和餐后2h血糖。评价各组大鼠血糖变化和成模率。实验结束时测定血清胰岛素(INS)、甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)等。HE染色和胰岛素免疫组化观察胰岛细胞形态学特点。结果20mg/kg注射组成模率较低(30%);25mg/kg注射组成模率较高(73.3%),血糖中度升高并且稳定,胰岛结构完整,β细胞数量和细胞质内棕色颗粒有所减少;30mg/kg的STZ注射组血糖较高,死亡率较高,并且胰岛和β细胞数量极少,小胰岛多见,形状不规则,出现空泡样变性。结论高脂、高糖饲养8周后联合小剂量STZ25mg/kg能够造成更具有代表人类2型糖尿病病理生理特征的大鼠模型。     

生命早期经饲料补充维生素D对链脲菌素致小鼠糖尿病的影响

目的探讨生命早期经饲料补充维生素D对链脲菌素作用小鼠空腹血糖和胰岛素水平,糖尿病发病率,以及链脲菌素致胰岛损伤的影响。方法 C57BL/6鼠离乳后分别饲喂标准饲料和补充维生素D(VD)饲料9周后注射链脲菌素(STZ),继续喂养4周,注射STZ后每周末测定空腹血糖,计算糖尿病发病率,4周后测血清胰岛素水平,并采用HE染色法观察胰腺形态学变化。结果①生命早期补充VD能降低STZ作用小鼠的空腹血糖水平,并以补充高剂量VD的降糖效果最好,其在注射STZ后4周血糖值明显低于糖尿病模型组(P<0.01);②生命早期补充VD降低STZ致小鼠糖尿病发病率,并以补充高剂量VD的干预效果最好,其在注射STZ后4周时糖尿病发病率为0%,完全抑制糖尿病的发病(P<0.01);③生命早期补充高剂量和中剂量VD明显上调STZ作用小鼠的血清胰岛素水平(P<0.05),并以补充高剂量VD的上调作用最显著(P<0.01)。④生命早期补充高剂量和中剂量VD对STZ致胰岛损伤有明显保护作用,且以补充高剂量VD的保护作用最好。结论生命早期补充一定量VD能降低STZ作用小鼠的血糖水平和糖尿病发病率,上调血清胰岛素水平,改善STZ对胰岛细胞的损伤,且均以补充高剂量VD的作用最显著。     

苦瓜粗多糖提取物降血糖作用的实验研究

目的　研究苦瓜粗多糖提取物(CPS)对正常及糖尿病小鼠血糖调节作用。方法　采用2 4只正常小鼠进行口服葡萄糖耐量试验,一次性经口给予动物葡萄糖3g kgbw ,实验组同时一次性给予CPS 1g kgbw ,对照组给予等量的生理盐水;应用1型和2型糖尿病模型小鼠,分别在随机进食和空腹情况下一次性经口给予CPS(1g kgbw) ,测定给药后2h、4h血糖水平,并与对照组血糖进行比较。结果　葡萄糖耐量试验中,实验组小鼠给予CPS 0 . 5h、1h后血糖水平显著低于对照组(分别低于对照组16 4 %和16 . 5 % ) ,差别具有显著性意义(P <0 .0 5和P <0 . 0 1)。2种糖尿病模型动物服用CPS后,各时点血糖水平较对照组显著下降(P <0 . 0 5 )。结论　苦瓜多糖粗提物对正常小鼠糖耐量有改善作用,能显著降低糖尿病模型动物随机及空腹血糖。     

海带多糖对糖尿病小鼠血糖的调节作用

目的 :　研究海带多糖 ( Laminarina Japonica Polysaccharides LJPS)对四氧嘧啶所致糖尿病小鼠血糖的调节作用。方法 :　从小鼠尾静脉注射 55mg/kg bw剂量的四氧嘧啶造成糖尿病小鼠模型 ,按 1 2 5、2 50、50 0 mg/kg bw剂量的海带多糖连续灌胃糖尿病小鼠 3w后 ,测定空腹血糖、尿素氮、血清钙、血清胰岛素含量等指标并做胰腺病理检查。结果 :　海带多糖能明显降低糖尿病小鼠血糖和尿素氮 ,其血糖降低率分别为 34.96% ,2 0 .70 % ,2 6.82 % ,增加糖尿病小鼠的血清钙和血清胰岛素含量 ,对四氧嘧啶所致的胰岛损伤具有明显的恢复作用。结论 :　海带多糖对糖尿病小鼠有降血糖及保护胰岛细胞的功能。     

苦瓜水提取物降血糖作用动物实验研究

目的观察苦瓜水提取物对II型糖尿病小鼠的降血糖作用。方法采用高脂饲料喂饲断乳小鼠制备II型糖尿病模型,选血糖≥8 mmol/L者分入对照组和2个剂量组。剂量组分别给予0.25、1.00 g/kg.bw剂量的苦瓜水提取物。30 d后测定小鼠空腹血糖、糖耐量、血生化指标和血清MDA、SOD。同步给予正常小鼠1.00 g/kg.bw剂量的苦瓜水提取物观察其对正常小鼠血糖的影响。结果苦瓜水提取物0.25 g/kg.bw剂量能显著降低高血糖小鼠空腹血糖,显著提高实验前后血糖下降百分率(P0.01),对高血糖小鼠的糖耐量无显著影响。1.00 g/kg.bw剂量能改善高血糖小鼠血清胆固醇升高的状态,对升高的血清MDA有降低作用。但进一步加剧了高血糖小鼠血清总蛋白、白蛋白降低的状态。苦瓜水提取物对正常小鼠的血糖无显著影响。结论苦瓜水提取物可降低II型糖尿病小鼠的高血糖,但可导致血清总蛋白、白蛋白降低。临床上应用时应加注意。     

Antihyperglycemic activity of Prunella vulgaris L. in streptozotocin-induced diabetic mice

Prunella vulgaris L. (Labiatae) has been reported to have a wide range of health benefits in oriental medicine. This study for the first time is to examine the antihyperglycemic effects of P. vulgaris in streptozotocin (STZ)-induced diabetic ICR mice (STZ diabetic mice). The effects of P. vulgaris L. aqueous-ethanol extract (PVE) on blood glucose, exogenous insulin sensitivity and plasma insulin levels were investigated. In four doses of extracts from the spikes of P. vulgaris, extract at dose of 100 mg/kg significantly suppressed the rise in blood glucose after 30 min in the acute glucose tolerance test. Furthermore, this dose was applied in the fellow experiments. A significant decrease in blood glucose levels was observed after treatment of PVE. A combination of PVE and glibenclamide produced a greater effect in blood glucose level than using glibenclamide or PVE alone. PVE enhanced and prolonged the antihyperglycemic effects of exogenous insulin on STZ diabetic mice. Plasma insulin levels were increased with glibenclamide treatment in STZ diabetic mice, whereas such effect was not observed with PVE. These results indicated that P. vulgaris enhances the antihyperglycemic effects of exogenous insulin without stimulating insulin secretion, indicating that insulin sensitivity is increased in STZ diabetic mice.     

硒蛋白对糖尿病小鼠血糖、Ca2+转运以及NO系统影响的实验研究

目的研究硒蛋白对糖尿病小鼠血糖、Ca2+转运及NO系统的调控作用.方法体重(20.3±1.7)g昆明种雄性小鼠,腹腔注射200mg/kgbw,2%的四氧嘧啶造糖尿病(DM)模型.实验分6组正常对照组(Ⅰ)、正常+硒蛋白组(Se 100μg/kgbw)(Ⅱ)、糖尿病对照组(Ⅲ)、DM+硒蛋白低剂量组(Se 100μg/kgbw)(Ⅳ)、DM+硒蛋白高剂量组(Se 300μg/kgbw)(Ⅴ)、DM+亚硒酸钠组(Se 100μg/kgbw)(Ⅵ).结果Ⅴ组血糖(20.4±6.3)mmol/L明显低于Ⅲ组(45.3±3.3)mmoi/L,P＜0.05;肾脏三磷酸腺苷酶(Ca2+-ATPase)活性,Ⅴ组0.90±0.5明显高于Ⅲ组(0.35±0.1)μmol/(h·mg prot),P＜0.05;一氧化氮合酶(NOS)活性,Ⅴ组(25.0±4.3)U/ml明显低于Ⅲ组(35.2±4.4)U/ml,P＜0.05.结论补硒剂量为Se 300μg/kgbw的硒蛋白能够显著的降低糖尿病小鼠血糖、提高肾脏Ca2+-ATPase活性和降低血浆NOS活性.     

Glyceollin-containing fermented soybeans improve glucose homeostasis in diabetic mice

ObjectiveOur previous in vitro study demonstrated that glyceollins help normalize glucose homeostasis by potentiating β-cell function and survival in insulinoma cells as well as improving glucose utilization in adipocytes. Here, we investigated whether fermented soybeans containing glyceollins had an antidiabetic action in type 2 diabetic animals.MethodsThe diabetic mice, their diabetes induced by intraperitoneal injections of streptozotocin (20 mg/kg bw), were administered a high fat diet with no soybeans (control), 10% unfermented soybeans and 10% fermented soybeans containing glyceollins, respectively, (FSG) for 8 weeks. As positive controls, rosiglitazone (20 mg/kg/bw) was given to diabetic mice fed a no soybean diet and non-diabetic mice were also placed on the same diet.ResultsAmong the diabetic mice, FSG-treated mice exhibited the lowest peak for blood glucose levels with an elevation of serum insulin levels during the first part of oral glucose tolerance testing. FSG also made blood glucose levels drop quickly after the peak and it decreased blood glucose levels more than the control during insulin tolerance testing. This improvement was associated with increased hepatic glycogen accumulation and decreased triglyceride storage. The phosphorylation of Akt, AMP-kinase, and acetyl-CoA carboxylase in the liver was potentiated by FSG, whereas phosphoenolpyruvate carboxykinase expression decreased. The enhancement of glucose homeostasis was comparable to the effect induced by rosiglitazone, a commercial peroxisome proliferator-activated receptor-γ agonist, but it did not match the level of glucose homeostasis in the non-diabetic mice.ConclusionGlyceollin-containing FSG improves glucose homeostasis, partly by enhancing hepatic insulin sensitivity in type 2 diabetic mice.     

Hypoglycemic activity of the fruit of the Momordica charantia in type 2 diabetic mice

The antidiabetic activity of Momordica charantia L. (Cucurbitaceae) was investigated in KK-Ay mice, an animal model with type 2 diabetes with hyperinsulinemia. The water extract of the fruit of Momordica charantia L. (MC) reduced the blood glucose of KK-Ay mice 3 weeks after oral administration (p<0.01) and also significantly lowered the serum insulin of KK-Ay mice under similar conditions (p<0.01). However, MC did not affect the blood glucose in normal mice. MC-treated KK-Ay mice blood glucose significantly decreased in an insulin tolerance test. Moreover, the muscle content of facilitative glucose transporter isoform 4 (GLUT4) protein content in the plasma membrane fraction from muscle significantly increased in the orally MC-treated mice when compared with that of the controls (p<0.01). These results suggest that the antidiabetic effect of MC is derived, at least in part, from a decrease in insulin resistance because of the increase of GLUT4 protein content in the plasma membrane of the muscle.     

明日叶查尔酮对2型糖尿病大鼠肝细胞胰岛素受体与胰岛素受体底物-2 mRNA表达的影响

目的研究明日叶查尔酮(Ashitabe chalcone,AC)对糖尿病大鼠肝细胞胰岛素受体(insulin receptor,InsR)和胰岛素受体底物-2(insulin receptor substrate-2,IRS-2)mRNA表达的影响。方法将用高脂饲料喂养加链尿佐菌素腹腔注射诱发的2型糖尿病大鼠随机分为糖尿病对照组和高、低剂量AC组,每组10只,均喂饲高脂饲料,分别每日经口灌胃给予明日叶查尔酮的剂量为0、30、10 mg/kg。另设一个正常对照组为正常大鼠喂饲普通饲料,实验周期4 w。用放射免疫分析法检测血清胰岛素水平、逆转录聚合酶链式反应方法检测肝细胞InsR和IRS-2 mRNA表达水平、免疫组化法测肝细胞InsR蛋白表达水平、葡萄糖氧化酶法测血糖含量。结果与正常对照组比较,糖尿病对照组空腹血糖和血清胰岛素升高,而InsR和IRS-2 mRNA表达水平降低。与糖尿病组比较,高剂量AC组空腹血糖和血清胰岛素降低,而InsR和IRS-2mRNA表达水平升高,各项差异均有显著性意义(P<0.05)。结论明日叶查尔酮可上调2型糖尿病大鼠肝细胞InsR和IRS-2mRNA表达水平,改善胰岛素抵抗状况。     

Antihyperglycemic and hypolipidemic effects of alpha, beta-amyrin, a triterpenoid mixture from Protium heptaphyllum in mice

ABSTRACT: BACKGROUND: Pentacyclic triterpenes in general exert beneficial effects in metabolic disorders. This study investigated the effects of alpha, beta-amyrin, a pentacyclic triterpene mixture from the resin of Protium heptaphyllum on blood sugar level and lipid profile in normal and streptozotocin (STZ)-induced diabetic mice, and in mice fed on a high-fat diet (HFD). FINDINGS: Mice treated with alpha, beta-amyrin (10, 30 and 100 mg/kg, p.o.) or glibenclamide (10 mg/kg, p.o.) had significantly reduced STZ-induced increases in blood glucose (BG), total cholesterol (TC) and serum triglycerides (TGs). Unlike glibenclamide that showed significant reductions in BG, TC and TGs in normoglycemic mice, alpha, beta-amyrin did not lower normal blood sugar levels but at 100 mg/kg, manifested a hypolipidemic effect. Also, alpha, beta-amyrin effectively reduced the elevated plasma glucose levels during the oral glucose tolerance test. Moreover, the plasma insulin level and histopathological analysis of pancreas revealed the beneficial effect of alpha, beta-amyrin in the preservation of beta cell integrity. In mice treated orally with alpha, beta-amyrin (10, 30 and 100 mg/kg) or fenofibrate (200 mg/kg), the HFD-associated rise in serum TC and TGs were significantly less. The hypocholesterolemic effect of alpha, beta-amyrin appeared more prominent at 100 mg/kg with significant decreases in VLDL and LDL cholesterol and an elevation of HDL cholesterol. Besides, the atherogenic index was significantly reduced by alpha, beta-amyrin CONCLUSIONS: These findings reflect the potential antihyperglycemic and hypolipidemic effects of alpha, beta-amyrin mixture and suggest that it could be a lead compound for drug development effective in diabetes and atherosclerosis.