重组人胰岛素样生长因子-1对db/db小鼠应激性血糖升高的保护作用

目的:研究重组人胰岛素样生长因子(rhIGF)-1对2型糖尿病(T2DM)伴胰岛素抵抗(IR)小鼠应激性血糖升高的治疗作用。方法:以瘦素受体基因缺陷型db/db小鼠为动物模型,电脉冲刺激诱发应激性高血糖。给予高剂量胰岛素或rhIGF-1进行干预,观察血糖的变化情况。Real time-PCR及Western blot分别检测骨骼肌组织内GLUT4基因的表达水平及GLUT4蛋白含量。结果:在8周龄时瘦素受体基因缺陷的db/db小鼠表现出了明显的肥胖、高血糖及高胰岛素血症。应激后组间血糖水平的差异有统计学意义(F组间=48.915,P<0.05),组内不同时间点血糖水平差异无统计学意义(F时间=1.295,P>0.05),组间和时间无交互效应(F交互=1.046,P>0.05)。采取干预措施后,组间血糖水平差异有统计学意义(F组间=36.947,P<0.05),不同时间点血糖水平差异有统计学意义(F时间=13.880,P<0.05),且组间和时间存在交互效应(F交互=11.769,P<0.05)。IGF-1可显著增加db/db小鼠骨骼肌组织中GLUT4基因的表达及GLUT4蛋白在细胞膜中的含量。结论:rhIGF-1对T2DM小鼠被诱发的应激性高血糖具有较胰岛素更好的控制作用,此作用可能是因骨骼肌细胞中GLUT4的表达及转位增加所致。     

白木香叶95%乙醇提取物在db/db糖尿病小鼠上的降糖作用(英文)

白木香叶为中国广东省治疗糖尿病的民间药物,关于其降糖作用和机制未见报道。本研究采用白木香叶95%乙醇提取物(AE),灌胃给药于db/db2型糖尿病小鼠,4周之后发现AE高剂量组(600 mg/kg)具有降低db/db小鼠空腹血糖和糖化血红蛋白水平,改善糖耐量的作用。作用机制研究表明,AE可能是通过激活腺苷酸活化蛋白激酶(AMPK),起到了改善胰岛素抵抗,降低血糖的作用,并且AE未表现出引起动物体重增加的副作用,可能成为噻唑烷二酮之外的治疗肥胖相关糖尿病药物的新选择。     

自发性2型糖尿病小鼠db/db的生物学特性

目的观察自发性2型糖尿病小鼠C57BK/KsJ-db/db的生物学特性。方法从第5周起,每周测定db/db及db/+小鼠体质量、随机血糖;从第6周起,每2周测定血清胰岛素、甘油三酯、胆固醇水平;从第8周起,每4周测定糖化血清蛋白含量;20周龄处死,脏器、脂肪称质量,部分组织用体积分数10%中性甲醛固定,制作病理切片。结果 db/db小鼠体质量、血糖、胰岛素、GSP、甘油三酯及总胆固醇水平均明显高于同龄同性别对照组;与同龄同性别对照组相比,db/db小鼠各脂肪系数显著增高,而脾脏及肾脏则相对萎缩,脾脏及雄性小鼠的肾脏与对照组相比差异极显著;db/db小鼠胰岛细胞明显肥大;肝细胞大片坏死,且伴随炎细胞浸润及严重脂肪变性;肾小球肥大,可见炎性细胞浸润;心肌细胞间隙增大,且发生肥大变性。结论 db/db小鼠在生长发育过程中表现出肥胖、高血糖、高胰岛素血症,GSP、甘油三酯、总胆固醇水平升高,胰岛功能不足,肝脏、肾脏、心脏病变,适用于进行2型糖尿病研究。     

千金黄连方对db/db小鼠血糖的影响

目的 探讨千金黄连方对2型糖尿病模型动物db/db小鼠血糖的影响。方法 C57BL/6J小鼠10只（雌雄各半）作为对照组,将db/db小鼠60只（雌雄各半）按血糖值随机分为6组：模型组、二甲双胍（0.25 g·kg^-1）组、金芪降糖片（4.2 g·kg^-1）组和千金黄连方高、中、低剂量（生药13.00、6.50、3.25 g·kg^-1）组。每天ig给药1次,给药体积20 mL·kg^-1,对照组及模型组ig给予等量去离子水。血糖仪测定千金黄连方给药1次对糖耐量、空腹血糖的影响及多次给药对空腹血糖、糖耐量、混合饮食餐后血糖、淀粉耐量（碳水化合物饮食餐后血糖）的影响;连续给药12周后,试剂盒法检测血清中糖化血清蛋白（GSP）、糖化血红蛋白（GHb）、胰岛素水平;小鼠放血处死后,剪开腹部,取腹部脂肪称质量,计算脂肪系数;HE染色后对肝组织进行病理学检查。结果 给药1次,与模型组比较,给药后1~2 h千金黄连方高剂量能显著降低小鼠空腹血糖值和糖耐量血糖值（P<0.05、0.01）。与模型组比较,多次给予千金黄连方能显著降低小鼠空腹血糖值、显著降低葡萄糖耐量血糖值、显著降低混合饮食餐后血糖值和淀粉耐量血糖值（P<0.05、0.01、0.01）。与模型组比较,千金黄连方高、中、低剂量组小鼠GHb、GSP及胰岛素水平均显著下降（P<0.05、0.01、0.001）;高、中剂量组小鼠腹部脂肪系数显著下降（P<0.05、0.01）;高、低剂量对肝脏空泡变性程度有减轻作用。结论 千金黄连方能显著降低db/db小鼠空腹血糖,改善糖耐量异常及增强胰岛素敏感性,显著减少腹部脂肪系数,对肝细胞的损伤也有一定的改善作用;其降血糖作用与二甲双胍相当,强于金芪降糖片,其改善胰岛素抵抗、增加胰岛素敏感性的作用强于二甲双胍和金芪降糖片。     

牛蒡子苷对自发型糖尿病db/db小鼠降血糖作用的实验研究

目的：观察牛蒡子苷对db/db自发型糖尿病小鼠的降血糖作用及其潜在的作用机制。方法：40只db/db小鼠随机分为5组：模型对照组,牛蒡子苷75,150,300 mg·kg^-1组和二甲双胍300 mg·kg^-1组,同时设置db/m小鼠空白对照组,灌胃给予相应药物或溶媒,连续4周。给药3周后,进行口服糖耐量试验。4周给药结束后,小鼠禁食12 h,称体质量,检测空腹血糖值（FBG）,处死动物,取血清,检测胰岛素（INS）、糖化血清蛋白（GSP）、三酰甘油（TG）、总胆固醇（TC）和脂联素（APN）含量。结果：与模型对照组比较,牛蒡子苷中、高剂量能显著降低db/db小鼠FBG、INS、GSP、TG、TC和APN的血清浓度,改善小鼠糖耐量（P〈0.05或0.01）。结论：牛蒡子苷能显著改善db/db小鼠糖脂代紊乱,减轻胰岛素抵抗,其作用机制可能与上调脂联素表达有关。     

脉冲电磁场对db/db鼠胰岛素抵抗的改善作用

目的研究脉冲电磁场对胰岛素抵抗的治疗效果,为2型糖尿病提供新的治疗手段。方法以雌性C57BL/KsJ小鼠为对照,16只雌性C57BL/6Jdb/db小鼠随机分为db/db组及脉冲电磁场处理组(PEMF组),db/db组不予特殊处理,PEMF组在频率15 Hz,场强20 Gs的脉冲电磁场中接受刺激2 h/d,共12周。实验结束后检测血糖、血清胰岛素,计算HOMA-IR;检测肝三酰甘油、丙二醛及谷胱甘肽含量。结果与db/db组小鼠相比,PEMF组小鼠血糖、血清胰岛素含量及HOMA-IR降低(P<0.05);肝三酰甘油、丙二醛含量降低,谷胱甘肽含量升高(P<0.05)。结论脉冲电磁场能够改善db/db鼠胰岛素抵抗,减轻肝脂肪变,降低肝氧化应激水平。     

基因缺陷型2型糖尿病模型动物db/db小鼠早期生物学特性研究

目的研究基因缺陷型2型糖尿病模型动物db/db小鼠的早期生物学特性,为db/db小鼠应用于降糖药物的研究奠定基础。方法采用db/db小鼠为模型组动物,db/m小鼠为对照组动物,测定两组小鼠的体质量、食量、饮水量、空腹血糖、正常饮食血糖、糖耐量、胰岛素耐量;于第14周眼底静脉丛取血,分离血清,测定糖化血清蛋白（GSP）、三酰甘油（TG）、总胆固醇（TC）;取肝、胰腺、腹部脂肪等主要脏器组织进行组织病理学检查。结果与对照组比较,db/db小鼠体质量、食量、饮水量显著增加;空腹血糖及正常饮食血糖显著升高,整个实验期血糖水平稳定;糖耐量异常、胰岛素耐量异常,对外源胰岛素敏感性显著降低;血清GSP、TG、TC含量显著升高,腹部脂肪质量显著增加,肝组织不同程度的空泡变性,脂肪组织中脂肪细胞体积增大,胰腺中胰岛细胞胞浆减少、血管扩张。结论 db/db小鼠早期脂质代谢紊乱,血糖、血脂显著升高,糖耐量及胰岛素耐量异常,血糖水平稳定,是研究2型糖尿病较为理想的模型。     

大黄酸对db/db小鼠胰岛功能及炎症氧化损伤标志物表达的影响

目的通过先天性2型糖尿病动物模型db/db小鼠,探讨大黄酸对胰岛功能及炎症、氧化损伤标志物表达的影响。方法选取30只4周龄db/db雄性小鼠,随机分成治疗组和对照组,每组15只。治疗组每日固定时间给予大黄酸(120mg/kg,1%纤维素钠溶解)灌胃,对照组给予相同体积的1%纤维素钠,连续给药8周。投药结束后行经腹腔葡萄糖耐量试验(IPGTT)并测定胰岛素水平,用曲线下面积(AUC)代表胰岛素分泌水平,并通过计算IPGTT的0~30min胰岛素AUC评估早期胰岛素分泌功能。同时对小鼠胰腺进行胰岛素、核因子-κB(NF-κB)及8-羟基脱氧鸟苷(8-OHdG)免疫组织化学染色。结果与对照组相比,治疗组糖负荷后0,30,60,120min的血糖水平明显下降,而30,60,120min的胰岛素水平明显升高,尤其是早期相胰岛素水平升高更明显。同时,大黄酸治疗组小鼠胰岛素染色明显增强,NF-κB及8-OHdG表达明显受抑制。结论早期大黄酸治疗可以明显改善db/db小鼠的葡萄糖耐量,恢复早期胰岛素分泌功能,保护胰岛功能;同时早期大黄酸治疗明显减少炎症、氧化损伤标志物的表达。     

自发性2型糖尿病模型db/db小鼠生物学特性研究

目的对db/db小鼠进行生物学特性研究,满足糖尿病研究的需要。方法在试验周期内,测定db/db小鼠的空腹血糖、体质量及摄食饮水量,并测定21周龄模型动物的糖耐量、血中胰岛素、胰高血糖素、三酰甘油、总胆固醇等指标的水平,进行胰腺的免疫组化双重染色及主要脏器的病理学检查,并与db/m小鼠进行比较。结果与对照组db/m小鼠比较,db/db小鼠过度肥胖,伴有高血糖、胰岛素抵抗、脂质代谢紊乱,且肝脏和胰腺组织均出现明显病变,胰腺免疫组化双重染色结果与血液学测定结果一致,并可观察到胰岛中A细胞和B细胞的分布变化情况。结论对自发性2型糖尿病模型db/db小鼠所做的相关生物学特性检测,可供糖尿病研究参考。     

荞麦花叶发酵提取物对2型糖尿病db/db小鼠心肌损伤的影响

目的探讨荞麦花叶发酵提取物(EFBFL)对自发肥胖2型糖尿病db/db小鼠心肌损伤的保护作用及其可能的机制。方法 9周龄♂db/db小鼠随机分为EFBFL高(EFBFL-H,0.1 g·kg~(-1))、低(EFBFL-L,0.05 g·kg~(-1))剂量组,二甲双胍对照组,模型对照组,每组10只。同时以10只db/m小鼠为正常对照组。各组均每天灌胃给药1次,连续8周。于给药前及给药后第2、4、6、8周末检测小鼠随机血糖(RBG),8周后处死取血清检测肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)和糖基化终末代谢产物(AGEs)含量;HE染色光镜下观察心肌组织形态学改变,电镜下观察心肌超微结构;免疫组化法和Western blot法检测心肌组织葡萄糖转运蛋白4(Glut4)表达。结果 EFBFL能有效抑制db/db小鼠心肌细胞损伤及心肌纤维化的病理进程,降低小鼠血糖及血清中CK、CK-MB、AGEs的含量,增加小鼠心肌组织Glut4蛋白表达水平。结论 EFBFL对自发肥胖2型糖尿病db/db小鼠心肌损伤具有抑制作用,其机制可能与降低小鼠血糖、抑制AGEs的产生及促进心肌细胞Glut4蛋白的表达有关。     

Hepatic metabolism of sulfur amino acids in db/db mice

To determine the effect of type-2 diabetes and obesity on the hepatic metabolism of sulfur amino acids, hepatic sulfur amino acid metabolism was determined in db/db mice. Hepatic methionine was markedly decreased in db/db mice, although the hepatic activity of betaine homocysteine methyltransferase was increased. The decrease in hepatic methionine was reflected by decreased sulfur-containing methionine metabolites, including S-adenosylmethionine, homocysteine, cysteine, and hypotaurine in liver and plasma. In contrast, S-adenosylhomocysteine, putrescine, and spermidine were increased in db/db mice. The hepatic level and activity of methionine adenosyltransferase I/III, an S-adenosylmethionine synthesizing enzyme, were significantly increased. These results suggest that increased polyamine synthesis, in conjunction with decreased hepatic methionine levels, is partly responsible for the reduction in hepatic S-adenosylmethionine. Decreased homocysteine in liver and plasma may be attributable to the decrease in hepatic methionine and upregulation of hepatic betaine homocysteine methyltransferase. Glutathione in liver and plasma did not change despite decreased γ-glutamylcysteine ligase activity. The decreased hepatic hypotaurine may be attributable to the downregulation of cysteine dioxygenase. The major finding of this study is that db/db mice exhibited decreases in hepatic methionine and its sulfurcontaining metabolites.     

Urocortin ameliorates diabetic nephropathy in obese db/db mice

BACKGROUND AND PURPOSE: Hyperglycaemia induces overproduction of mitochondrial reactive oxygen species (ROS) in endothelial cells, which is believed to be a major molecular mechanism underlying complications of diabetes, including diabetic nephropathy. Impairment of endothelium-dependent vasodilatation is found in type 2 diabetes. Urocortin is a 40 amino-acid peptide related to the corticotrophin-releasing factor (CRF) family, which suppresses production of ROS in endothelial cells and sustains endothelium-dependent relaxations of rat coronary artery. However, it is not clear if urocortin has any effect on diabetic nephropathy. EXPERIMENTAL APPROACH: Possible mechanisms underlying the effects of urocortin on diabetic nephropathy were investigated in db/db mice and cultured rat mesangial cells. KEY RESULTS: Urocortin decreased body weight, plasma levels of advanced glycation end-products, blood urea nitrogen and creatinine levels. However, food intake, plasma insulin and glucose levels remained unaffected. Superoxide dismutase activity was increased markedly, whereas malonaldehyde levels in kidney homogenate and sorbitol concentrations in red blood cells were decreased significantly in urocortin-treated mice. Urocortin significantly decreased glomerular extracellular matrix expansion and accumulation in kidney. Moreover, urocortin inhibited the overexpression of transforming growth factor-beta 1 and connective tissue growth factor in rat mesangial cells induced by 25 mM glucose. All the effects of urocortin, except sorbitol accumulation, were abolished by the non-selective CRF receptor blocker, astressin. CONCLUSION AND IMPLICATIONS: Urocortin could significantly ameliorate diabetic nephropathy and this effect was mediated via the CRF receptor.     

Improvement of mechanical heart function by trimetazidine in db/db mice

Aim:

To investigate the influence of trimetazidine, which is known to be an antioxidant and modulator of metabolism, on cardiac function and the development of diabetic cardiomyopathy in db/db mouse.

Methods:

Trimetazidine was administered to db/db mice for eight weeks. Cardiac function was measured by inserting a Millar catheter into the left ventricle, and oxidative stress and AMP-activated protein kinase (AMPK) activity in the myocardium were evaluated.

Results:

Untreated db/db mice exhibited a significant decrease in cardiac function compared to normal C57 mice. Oxidative stress and lipid deposition were markedly increased in the myocardium, concomitant with inactivation of AMPK and increased expression of peroxisome proliferator-activated receptor coactivator-1α (PGC-1α). Trimetazidine significantly improved systolic and diastolic function in hearts of db/db mice and led to reduced production of reactive oxygen species and deposition of fatty acid in cardiomyocytes. Trimetazidine also caused AMPK activation and reduced PGC-1α expression in the hearts of db/db mice.

Conclusion:

The data suggest that trimetazidine significantly improves cardiac function in db/db mice by attenuating lipotoxicity and improving the oxidation status of the heart. Activation of AMPK and decreased expression of PGC-1α were involved in this process. Furthermore, our study suggests that trimetazidine suppresses the development of diabetic cardiomyopathy, which warrants further clinical investigation.     

银杏叶提取物对db/db糖尿病小鼠胰岛功能的影响

目的探讨银杏叶提取物EGb761对胰岛分泌功能的影响及相关机制。方法 10只8周龄db/db小鼠随机分为两组,观察组(EGb761组)和糖尿病对照组(db/db组),每组各5只,分别给予EGb761 100 mg/(kg.d)和安慰剂灌胃。另选5只同周龄db/m小鼠给予安慰剂灌胃作为非糖尿病对照(db/m组)。每周监测体重、血糖,8周后行腹腔葡萄糖耐量试验并取胰腺行免疫组化检测,分析胰岛内烟酰胺腺嘌呤二核苷酸磷酸(nicotinamide adenine dinucleotide phosphate,NADPH)氧化酶表达情况。结果 EGb761组血糖、胰岛素分泌功能和胰岛素敏感性、胰岛内NADPH氧化酶gp91phox、p22phox亚基的表达水平、胰岛质量显著改善。结论 EGb761能够降低NADPH氧化酶的表达,减少氧化应激的来源,改善胰岛微环境,从而保护胰岛β细胞。     

滋阴益气活血泄浊法对db／db小鼠糖代谢的影响

目的：探讨滋阴益气活血泄浊法对db／db小鼠整体水平糖代谢的影响。方法选取12~14周龄雄性db／db小鼠,按空腹血糖及体质量随机分成模型组、阿卡波糖组、石斛合剂序贯组（以下简称序贯组）;选db／m为正常对照组。连续灌胃给药共6个循环（42d）。治疗前测各药物对淀粉耐量影响。每2周期测空腹血糖（FBG）,实验结束前测口服葡萄糖耐量（OGTT）和测定糖化血清蛋白（GSP）、血清胰岛素（Ins）以及各药物干预后的肠上皮α-葡萄糖苷酶活性。结果石斛合剂1方和2方单次给药均能明显降低db／db小鼠淀粉耐量30,60,120min血糖;随治疗循环数增加,序贯组的FBG逐步下降;与模型组比较,序贯组FBG、GSP和Ins显著下降（P<0.05）,改善葡萄糖耐量;石斛合剂1方、2方降低肠上皮α-葡萄糖苷酶活性（P<0.05）。结论石斛合剂有明确的α-葡萄糖苷酶抑制作用,序贯治疗能降低db／db小鼠的血糖相关指标,降低高胰岛素血症,表明滋阴益气活血泄浊法的降糖机制可能与抑制α-葡萄糖苷酶活性有关。