A < 1.7 cM interval is responsible for Dmo1 obesity phenotypes in OLETF rats

1. Dmo1 (Diabetes Mellitus OLETF type I) is a major quantitative trait locus for dyslipidaemia, obesity and diabetes phenotypes of male Otsuka Long Evans Tokushima Fatty (OLETF) rats. 2. Our congenic lines, produced by transferring Dmo1 chromosomal segments from the non-diabetic Brown Norway (BN) rat into the OLETF strain, have confirmed the strong, wide-range therapeutic effects of Dmo1 on dyslipidaemia, obesity and diabetes in the fourth (BC4) and fifth (BC5) generations of congenic animals. Analysis of a relatively small number of BC5 rats (n = 71) suggested that the critical Dmo1 interval lies within a < 4.9 cM region between D1Rat461 and D1Rat459. 3. To confirm the assignment of the Dmo1 critical interval, we intercrossed BC5 animals to produce a larger study population (BC5:F1 males; n = 406). For the present study, we used bodyweight at 18 weeks of age as an index of obesity; this phenotype is representative of the closely associated dyslipidaemia and hyperglycaemia phenotypes. 4. Interval mapping assigned logarithm of odds (LOD) peaks at the D1Rat90 marker (LOD = 9.11). One LOD support interval lies within the < 1.7 cM region between D1Rat461 and D1Rat459. 5. This large intercross study confirms that Dmo1 is likely localized within the interval.     

Dysfunction of aorta involves different patterns of intracellular signaling pathways in diabetic rats

Rat models of insulin-dependent (streptozotocin-induced) and independent (Otsuka Long-Evans Tokushima Fatty (OLETF)) diabetes had sustained and transient increases in blood glucose levels. Over-contraction due to norepinephrine was seen exclusively in streptozotocin rat aorta. Contraction was enhanced under high-glucose conditions in OLETF rats. In order to understand the association between these patterns of changes, total diacylglycerol was measured as a key element of phosphatidylinositol-turnover due to the conversion of some incorporated glucose into diacylglycerol. Streptozotocin rats had enhanced basal diacylglycerol. Both diacylglycerol kinase (metabolic enzyme of diacylglycerol) and total phosphatidylinositol turnover activities also increased on norepinephrine stimulation, independent of extracellular glucose level. On the other hand, diacylglycerol, diacylglycerol kinase and phosphatidylinositol turnover in OLETF rats increased under high glucose conditions in the absence of norepinephrine treatment. These results indicated that diacylglycerol and diacylglycerol kinase-mediated phosphatidylinositol turnover acceleration was influenced by an increase in glucose levels in OLETF rats or by receptor-mediated signals in streptozotocin rats including glucose desensitization based on submaximal incorporation. We suggest that the alteration of vascular dysfunction is induced by different factors in each type of diabetes.     

Mutated G-protein-coupled receptor GPR10 is responsible for the hyperphagia/dyslipidaemia/obesity locus of Dmo1 in the OLETF rat

1. We have confirmed the Diabetes Mellitus OLETF type I (Dmo1) effect on hyperphagia, dyslipidaemia and obesity in the Otsuka Long-Evans Tokushima Fatty (OLETF) strain. The critical interval was narrowed down to 570 kb between D1Got258 to p162CA1 by segregation analyses using congenic lines. 2. Within the critical 570 kb region of the Dmo1 locus, we identified the G-protein-coupled receptor gene GPR10 as the causative gene mutated in the OLETF strain. The ATG translation initiation codon of GPR10 is changed into ATA in this strain and, so, is unavailable for the initiation of translation. 3. The GPR10 protein has a cognate ligand, namely prolactin-releasing peptide (PrRP). Centrally administered PrRP suppressed the food intake of congenic rats that have a Brown Norway derived Dmo1 region (i.e. with wild-type GPR10), but did not suppress that of the OLETF strain, indicating that GPR10 is without function and could explain hyperphagia in the OLETF strain. 4. Moreover, when restricted in food volume to the same level consumed by the congenic strain, OLETF rats showed few differences in the parameters of dyslipidaemia and obesity compared with congenic strains. 5. Taken together, these results demonstrate that the mutated GPR10 receptor is responsible for the hyperphagia leading to obesity and dyslipidaemia in the obese diabetic strain rat.     

Nephrotoxic effects of lead nitrate exposure in diabetic and nondiabetic rats: Involvement of oxidative stress and the protective role of sodium selenite

Heavy metals are known to be toxic to organisms. The present study was undertaken to evaluate the protective effect of sodium selenite against lead nitrate (LN)‐induced nephrotoxicity in diabetic and nondiabetic rats. Animals were divided into eight groups where the first was served as a control, whereas the remaining groups were treated with sodium selenite (1 mg/kg b.w.), LN (22.5 mg/kg b.w.) and a combination of LN and sodium selenite and diabetic forms of these groups. Changes in antioxidant enzyme activities, malondialdehide levels, serum urea, uric acid, creatinine levels, body, and kidney weights and histopathological changes were determined after 28 days. LN caused severe histopathological changes, increment in urea, uric acid, creatinine, and MDA levels, also decreasing in antioxidant enzyme activities, body, and kidney weights. In sodium selenite + LN group, we observed the protective effect of sodium selenite on examining parameters. Also diabetes caused alterations on these parameters compared with nondiabetic animals. We found that sodium selenite did not show protective effect on diabetes caused damages. As a result, LN caused nephrotoxicity and sodium selenite alleviated this toxicity but sodium selenite did not protect kidneys against diabetes mediated toxicity. Also, LN caused more harmfull effects in diabetic groups compared with nondiabetic groups. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1229–1240, 2016.     

Effects of losartan in combination with or without exercise on insulin resistance in Otsuka Long–Evans Tokushima Fatty rats

Hypertension often complicates type 2 diabetes mellitus, and angiotensin converting enzyme inhibitor treatment has been shown to improve insulin resistance in such cases. However, the effect of angiotensin II type-1 (AT₁) receptor antagonists on insulin resistance is still controversial. To gain further information on this effect, we examined the effect of losartan on insulin resistance in Otsuka Long–Evans Tokushima Fatty (OLETF) rats, a model of type 2 diabetes mellitus. Losartan administration alone lowered systolic blood pressure, but did not improve oral glucose tolerance test or insulin resistance in OLETF rats. However, the administration of losartan with exercise significantly improved both systolic blood pressure and insulin resistance relative to control OLETF rats. On the other hand, losartan treatment, regardless of exercise, increased glucose uptake in excised soleus muscle and fat cells. To explore the beneficial effect of losartan on skeletal muscle glucose uptake, we examined intracellular signaling of soleus muscle. Although Akt activity and glucose transporter type 4 (GLUT4) expressions were not affected by losartan with or without exercise, extracellular signal-regulated kinase (ERK1/2) and p38 mitogen-activated protein (MAP) kinase activities were increased by both interventions. These results indicate that angiotensin AT₁ receptor antagonist improved local insulin resistance, but not systemic insulin resistance. These findings may explain the controversy over the effect of angiotensin AT₁ receptor antagonists on insulin resistance in clinical use. The enhancing effect of angiotensin AT₁ receptor antagonist on skeletal muscle glucose uptake may be attributable to MAP kinase activation or other mechanisms rather than phosphatidylinositol 3-kinase activation.     

依那普利对2型糖尿病大鼠肠系膜血管内皮细胞的保护作用

目的　糖尿病血管病变的初始原因是血管内皮细胞损害。本研究观察依那普利对糖尿病大鼠肠系膜血管内皮细胞是否有保护作用。方法　大鼠用高脂饮食饲养 4周后 ,ip链佐霉素 30mg·kg- 1诱导 2型糖尿病 ,继续饲以高脂饮食 4周后 ,依那普利组给予依那普利 10mg·kg- 1·d- 1,ig ,连续 4周。采用大鼠离体肠系膜血管灌流技术 ,用去甲肾上腺素 1μmol·L- 1预收缩血管 ,再给予乙酰胆碱 (ACh) 1μmol·L- 1使血管舒张。观察ACh的舒张率来反映内皮细胞功能。结果　糖尿病大鼠肠系膜血管ACh舒张率为 (33±8) % ,较对照组 (79± 8) %明显降低 ,依那普利治疗组血管ACh舒张率为 (5 2± 6 ) % ,较糖尿病组明显改善。用皂素去内皮后 ,三个组肠系膜血管对ACh舒血管的反应性均明显降低 ,三组间无显著性差异。去内皮前后 ,三个组肠系膜血管对硝普钠舒张血管的反应性无显著变化。结论　依那普利对 2型糖尿病大鼠肠系膜血管内皮细胞具有保护作用。     

Single-allele correction of the Dmo1 locus in congenic animals substantially attenuates obesity, dyslipidaemia and diabetes phenotypes of the OLETF rat

1. Whole-genome scans have identified Dmo1 as a major quantitative trait locus for dyslipidaemia and obesity in the Otsuka Long Evans Tokushima Fatty (OLETF) rat. 2. We have produced congenic rats for the Dmo1 locus through successive back-cross breeding with diabetic OLETF rats. Marker-assisted speed congenic protocols were applied to efficiently transfer chromosomal segments from non-diabetic Brown Norway (BN) rats into the OLETF background. 3. In the fourth generation of congenic animals, we observed a substantial therapeutic effect of the Dmo1 locus on lipid metabolism, obesity control and plasma glucose homeostasis. 4. We have concluded that Dmo1 primarily affects lipid homeostasis, obesity control and/or glucose homeostasis at fasting and is secondarily involved in glucose homeostasis after loading. 5. The results of the present study show that single-allele correction of a genetic defect of the Dmo1 locus can generate a substantial therapeutic effect, despite the complex polygenic nature of type II diabetic syndromes.     

牛磺酸对2型糖尿病大鼠胰腺线粒体氧化应激的影响

目的探讨牛磺酸对糖尿病大鼠胰腺线粒体氧化应激的影响。方法将30只Wistar大鼠随机分为正常对照组、糖尿病组(DM组)和牛磺酸治疗组(Tau组,采用20g.L-1牛磺酸生理盐水溶液治疗,200mg·kg-1),前两组注射等体积的生理盐水溶液。8wk后,测3组大鼠血浆葡萄糖、胰岛素、丙二醛(MDA),胰腺线粒体MDA、Ca2+、超氧化物歧化酶(SOD)及Na+,K+-ATP酶(Na+,K+-ATPase)和Ca2+,Mg2+-ATP酶(Ca2+,Mg2+-ATPase)的活性。结果①DM组大鼠血糖、MDA和胰腺线粒体MDA、Ca2+含量明显高于对照组(P<0.01),而血浆胰岛素水平、SOD、Na+,K+-AT-Pase和Ca2+,Mg2+-ATPase活性明显降低(P<0.05)。②Tau组大鼠血糖、MDA及胰腺线粒体Ca2+、MDA含量较DM组明显降低(P<0.05),血浆胰岛素水平、SOD、Na+,K+-ATPase和Ca2+,Mg2+-ATPase活性明显升高(P<0.05)。结论牛磺酸可减轻2型糖尿病大鼠胰腺线粒体氧化应激水平。     

灯盏花素对糖尿病大鼠肝脏保护作用的实验研究

目的　探讨灯盏花素对糖尿病大鼠肝脏保护作用。方法　建立STZ诱导的糖尿病模型 ,随机分 4组 :对照组、模型组、灯盏花素给药组、维生素E给药组 ,每组 10只 ,观察8wk。应用分光光度法检测肝组织MDA含量及SOD、CAT与GSH PX活性 ;HE染色对肝组织作病理检查 ;油红O染色观察肝组织脂肪浸润 ;肝组织ED1(单核 巨噬细胞表面标志 )免疫组织化学采用SABC技术。结果　灯盏花素给药组对糖尿病大鼠血糖、体重无明显影响 ,维生素E给药组可降低血糖 ,延缓体重下降。HE染色模型组部分肝细胞脂肪变性 ;各给药组对肝细胞保护效果较好。模型组肝细胞油红O染色评分为 2 11± 0 82 ,对照组为 0 35± 0 15 ,相比差异有显著性 (P <0 0 1) ;灯盏花素给药组评分为 0 75± 0 6 6 ,维生素E给药组评分为 1 13± 0 78,与模型组相比差异均有显著性 (P均 <0 0 1)。模型组肝组织MDA含量明显升高 ,SOD、CAT、GSH PX活性明显降低 ,各给药组均可降低肝组织MDA含量 ,提高SOD、CAT与GSH PX活性。免疫组织化学显示各给药组均能抑制糖尿病肝组织单核 巨噬细胞浸润的增加。结论　灯盏花素对糖尿病大鼠肝脏保护作用机制部分与抑制肝内脂肪浸润、氧化应激及巨噬细胞浸润有关。     

Antidiabetogenic action of Morus rubra L. leaf extract in streptozotocin‐induced diabetic rats

Objectives Researchers all over the world are exploring herbal supplements to control diabetes and its complications. This study evaluated the antidiabetic action of Morus rubra L. aqueous leaf extract through its effect on hyperglycaemia, dyslipidaemia and oxidative stress in streptozotocin‐induced diabetic rats. Methods The extract was orally administered to diabetic rats (100, 200 and 400 mg/kg body weight) daily for 21 days. Fasting blood glucose was measured on days 0, 7, 14 and 21. At the end of the experiment, blood samples were drawn to measure glucose tolerance, glycosylated haemoglobin, insulin, C‐peptide and lipid parameters. Antioxidant enzymes (superoxide dismutase and catalase), reduced glutathione and lipid peroxides were determined in blood and liver tissue. Histopathological examination of pancreatic tissue was also performed. Key findings The extract showed a dose‐dependent fall in fasting blood glucose. Treatment with 400 mg/kg extract produced a significant reduction in glycosylated haemoglobin with a concomitant elevation in plasma insulin and C‐peptide levels. The altered serum lipids in diabetic rats were significantly restored following treatment with the extract. In erythrocytes, as well as liver, the activity of antioxidant enzymes and content of reduced glutathione were found to be significantly enhanced, while levels of serum and hepatic lipid peroxides were suppressed in extract‐fed diabetic rats. Histopathological examination of pancreatic tissue revealed an increased number of islets and β‐cells in extract‐treated diabetic rats. Conclusions M. rubra aqueous leaf extract leads to control over hyperglycaemia and dyslipidaemia. The study also demonstrates its antioxidant nature, and hence it may be protective against diabetic complications.     

姜黄素类似物H8对糖尿病大鼠心脏的保护作用

目的 探讨姜黄素类似物H8对糖尿病大鼠心脏结构及功能的影响及机制。方法 采用随机数字表法将 24只雄性SD大鼠分为对照组、模型组和H8组,每组8只。模型组和H8组通过高脂高糖饮食诱导8周后腹腔注射链 脲佐菌素（STZ）建立2型糖尿病大鼠模型。H8组大鼠用H8（6 mg/kg）连续灌胃4周,对照组和模型组用等量羧甲基纤 维素钠连续灌胃4周。第4周末采用超声心动图评价各组大鼠心脏结构及功能变化。检测各组大鼠血液生化指标, 处死大鼠后检测心肌组织病理学改变,心肌组织中乳酸脱氢酶（LDH）、总超氧化物歧化酶（T-SOD）和丙二醛（MDA） 水平。结果 与对照组相比,模型组大鼠的左心室室壁运动减弱、心室重构明显、左室射血分数（LVEF）和短轴缩短 率（FS）降低,血糖、总胆固醇、三酰甘油水平明显升高,心肌细胞结构紊乱,心肌组织中LDH、MDA水平明显升高,T-SOD水平明显降低（P＜0.05）;与模型组相比,H8组大鼠左心室室壁运动增强、心室重构、LVEF和FS及心肌细胞排 列紊乱情况明显改善,血糖、总胆固醇、三酰甘油水平降低,心肌组织中LDH、MDA水平降低,T-SOD水平升高（P＜ 0.05）。结论 姜黄素类似物H8对糖尿病大鼠心肌损伤具有保护作用,其机制可能与抑制心室重构、改善心功能及 降低血糖、血脂及氧化应激因子水平有关。     

Effect of chronic treatment with trandolapril or enalapril on brain ACE activity in spontaneously hypertensive rats

The aim of the present study was to determine whether the new ACE inhibitor trandolapril was able to inhibit brain ACE activity in spontaneously hypertensive rats (SHRs). Therefore, we have measured ex vivo ACE activity in discrete brain areas of SHRs after a 2-week oral treatment with trandolapril (0.001, 0.01, 0.1 and 1 mg/kg/day). The effects of trandolapril were compared to those of enalapril (10 mg/kg/day), used as a reference compound. Enalapril induced a decrease in ACE activity in brain areas not protected by the blood brain barrier (subfornical organ and median eminence) and in cerebral cortex. Conversely, trandolapril at a dose of 0.01 mg/kg/day and above induced a dose-dependent inhibition of ACE activity in all brain areas assayed, including the supraoptic and paraventricular hypothalamic nuclei, septum, amygdala, hippocampus, cerebellar and cerebral cortex, nucleus of the tractus solitary and caudate nucleus. The inhibition was roughly similar in all brain areas studied. These data suggest that after chronic oral administration in SHRs, trandolapril or its metabolite, in contrast to enalapril or enalaprilat, was able to reach all brain areas of SHRs, including those protected by the blood brain barrier.     

海带在四氧嘧啶糖尿病大鼠模型中的降糖作用

目的探讨海带在四氧嘧啶糖尿病模型大鼠中的降血糖作用及其机制。方法健康♂Wistar大鼠60只,随机取10只作为对照组,其余50只腹腔注射四氧嘧啶建立高血糖动物模型,饲料中添加含有海带的饲料喂养干预治疗,分为低(2.5 g.kg-1)、中(10 g.kg-1)和高(25 g.kg-1)3个剂量组。自动血糖仪测大鼠空腹血糖(FBG),酶联免疫吸附法检测血清胰岛素(Insulin)水平,硫代巴比妥酸法检测血清脂质过氧化物丙二醛(MDA)含量,硝酸还原酶法检测血清一氧化氮(NO)含量,黄嘌呤氧化酶法测定血清超氧化物歧化酶(SOD)活性,化学比色法测定谷胱甘肽过氧化物酶(GSH-Px)活性。结果经海带治疗后,动物血清胰岛素水平较模型组升高(P<0.05),中、高剂量组动物FBG水平较模型组降低(P<0.05);其血清MDA和NO水平低于模型组,而血清SOD和GSH-Px活性高于模型组,其中中、高剂量组与模型组比较差异有显著性(P<0.05)。各指标在中剂量与高剂量组之间差异无显著性(P>0.05)。结论海带可通过增强机体的抗氧化作用,促进胰岛细胞分泌功能恢复而发挥降血糖作用,其理想剂量为每日10 g.kg-1。     

酮替芬对2型糖尿病大鼠胰岛β细胞氧化应激的影响

目的探讨酮替芬对2型糖尿病大鼠胰岛β细胞氧化应激的影响及其作用机制。方法以高糖高脂饲料对SD大鼠饮食诱导6周,随后一次性ip给予链脲佐菌素制备糖尿病大鼠模型,每天ig给予酮替芬0.09mg·kg-1,持续8周。检测空腹血糖(FBG)、游离脂肪酸(FFA)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、白介素6(IL-6)、肿瘤坏死因子α(TNF-α);检测胰腺丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性,检测胰腺细胞线粒体细胞色素C氧化酶(CCO)、琥珀酸脱氢酶(SDH)活性,电镜观察组织形态。结果与正常对照组比较,模型组大鼠FBG水平显著升高(P<0.01),FFA,TG和LDL-C水平升高(P<0.05),IL-6,TNF-α水平升高(P<0.05),MDA含量增加(P<0.05),SOD,CCO和SDH活性下降(P<0.05),与模型组比较,给予酮替芬同步干预后,FBG水平下降〔(24.5±2.7)vs(15.9±1.9)mmo·l L-1〕,FFA,TG和LDL-C水平由1.03±0.23,2.89±0.56和(2.05±0.33)mmo·l L-1分别降低至0.71±0.15,2.36±0.40和(1.56±0.30)mmol·L-1,IL-6,TNF-α水平由(58.33±4.94)ng·L-1和(1.98±0.45)μg·L-1分别下降至(33.84±3.82)ng·L-1和(1.12±0.27)μg·L-1,MDA含量减少〔(1.12±0.20)vs(0.87±0.20)μmol.g-1,SOD,CCO和SDH活性由(28.55±4.06)kU·g-1,(13.00±1.14)mmo·l g-1和(3.75±0.44)kU·g-1分别增加到(31.34±2.59)kU·g-1,(15.87±1.64)mmol·g-1和(4.92±0.50)kU·g-1,电镜结果显示,酮替芬的干预使胰岛β细胞形态结构得到改善。结论酮替芬能够降低糖尿病大鼠炎症介质和游离脂肪酸水平,减轻氧化应激损伤,使胰岛细胞线粒体功能改善,实现对胰岛β细胞的保护作用。     

2型糖尿病大鼠主动脉内皮细胞氧化损伤及缬沙坦的保护作用

目的探讨2型糖尿病大鼠氧化应激与主动脉内皮细胞损伤的关系,观察缬沙坦对两者的影响。方法SD大鼠,用长期高能量饮食加小剂量注射链脲佐菌素(STZ)的方法复制模型。注射STZ12wk末,将大鼠分为3组:正常组、糖尿病组、缬沙坦治疗组(24mg·kg-1·d-1,灌胃给药8wk)。在注射STZ12和20wk末,检测大鼠的内皮依赖性血管舒张反应及主动脉内皮形态,血清超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性,丙二醛(MDA)和一氧化氮(NO)含量,以及主动脉一氧化氮合酶(NOS)基因表达情况。结果①12wk末,糖尿病大鼠主动脉对低浓度乙酰胆碱(ACh)舒张反应减弱,局部内皮隆起,血清SOD、GSH-Px活性增强,MDA和NO含量增加,主动脉iNOS mRNA表达明显上调,eNOS mRNA表达无明显改变。②20wk末,糖尿病大鼠主动脉对各浓度ACh的反应性均减弱,主动脉内皮变性、坏死,血清SOD、GSH-Px活性减弱,MDA含量进一步增加,NO含量下降,主动脉iNOS mRNA表达仍升高,eNOS mRNA表达降低,缬沙坦治疗后能减轻主动脉病变,改善血清SOD、GSH-Px、MDA、NO及主动脉NOS mRNA表达的异常。结论糖尿病大鼠的氧化应激和NO系统的紊乱参与了主动脉病变过程,增强机体抗氧化能力及调节NO生成可能是缬沙坦发挥主动脉保护作用的机制之一。     

葛根素对链脲佐菌素诱导妊娠期糖尿病大鼠氧化应激损伤的保护作用

目的研究葛根素对链脲佐菌素诱导妊娠期糖尿病大鼠氧化应激损伤的保护作用。方法通过ip链脲佐菌素35mg/kg制备妊娠期糖尿病大鼠模型。选取64只模型大鼠并根据血糖水平随机分为模型组、葛根素40、80、160 mg/kg组,另选取16只同期妊娠的大鼠作为妊娠对照组,并取16只同龄非妊娠雌性大鼠作为非妊娠对照组。ig给药治疗,1次/d,给药容积为20 m L/kg,连续给药2周。分别于给药前和给药第7、14天测定空腹血糖水平。给药治疗2周后,测定丙氨酸转氨酶(ALT)、天门冬氨酸转氨酶(AST)、碱性磷酸酶(ALP)活性,检测血清中丙二醛(MDA)含量及总抗氧化能力(T-AOC)水平;测定肝脏组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和MDA含量。给药2周后,通过HE染色观察肝脏组织病理形态学改变。结果葛根素160 mg/kg组大鼠空腹血糖水平较模型组显著降低(P0.05、0.01)。与模型组比较,葛根素80、160 mg/kg组大鼠血清中ALT、AST活性和MDA含量均显著降低(P0.05、0.01),葛根素160 mg/kg组ALP活性显著降低(P0.01)、T-AOC水平显著升高(P0.05)。与模型组比较,葛根素80、160 mg/kg组肝脏组织中SOD活性显著升高(P0.05、0.01),MDA含量显著降低(P0.05、0.01);葛根素160 mg/kg组CAT活性显著升高(P0.01)。葛根素组大鼠肝脏组织病理形态学改变明显改善。结论葛根素对链脲佐菌素诱导妊娠期糖尿病大鼠氧化应激损伤具有保护作用,其作用机制可能与葛根素能够有效改善抗氧化酶活性、降低氧化应激损伤有关。     

黄芩苷对链脲佐菌素诱导的糖尿病模型大鼠血糖和血脂及腺苷酸活化蛋白激酶的影响

目的探讨黄芩苷对糖尿病大鼠血糖和血脂的影响及其作用机制。方法以高脂饲料(HFD)喂养雄性SD大鼠6周后,尾静脉iv给予链脲佐菌素(STZ)诱导2型糖尿病模型。黄芩苷组大鼠每天ip给予黄芩苷80 mg.kg-1,连续6周。给药0,3和6周时观察血糖、血总胆固醇(TC)、血三酰甘油(TG);给药6周时测定肝TC和丙二醛(MDA)水平;Western印迹法分析肝和骨骼肌磷酸化腺苷酸活化蛋白激酶(AMPK)及其下游靶蛋白乙酰辅酶A羧化酶(ACC)磷酸化水平。MTT法检测黄芩苷1～50μmol.L-1作用HepG2细胞24 h的细胞存活力;Western印迹法观察黄芩苷对AMPK活性的影响。结果黄芩苷80 mg.kg-1可明显降低糖尿病大鼠的血糖和血TC(P<0.05);黄芩苷可明显降低糖尿病大鼠肝TC和MDA水平(P<0.05)。糖尿病模型大鼠肝和骨骼肌磷酸化AMPK和磷酸化ACC的水平显著降低(P<0.01),而黄芩苷能激活AMPK,明显增加糖尿病大鼠肝和骨骼肌AMPK和ACC的磷酸化水平(P<0.01)。黄芩苷1和5μmol.L-1无细胞毒性,但能显著增加HepG2肝细胞磷酸化AMPK水平(P<0.01)。结论黄芩苷对糖尿病大鼠具有一定的保护作用,其作用机制可能与激活肝和骨骼肌AMPK有关。