胰岛素治疗逆转糖尿病小鼠肝脏的脂肪沉积

观察胰岛素治疗对糖尿病小鼠脂肪肝的影响.C57BL/6J小鼠高脂饲养12周后,甘精胰岛素皮下注射4周.结果 显示,与高脂组相比,胰岛素组腹腔葡萄糖耐量试验所有时间点血糖及血总胆同醇、甘油三酯(TG)均显著改善(P相似文献   

内源性雌激素对STZ诱导雌性小鼠糖尿病的保护作用研究

目的 研究内源性雌激素对糖尿病小鼠血糖、血清胰岛素水平和抗氧化能力的影响,探讨内源性雌激素对胰岛细胞和胰岛素敏感性可能的保护作用.方法 小鼠按体重随机分为4组,假手术组(Sham)、去卵巢手术组(Ovx)、假手术注射链脲佐菌素(streptozotocin,STZ)组(Sham+ STZ)、去卵巢手术注射STZ组(Ovx+STZ).切除小鼠两侧卵巢,腹腔注射STZ制糖尿病小鼠模型.跟踪测定体重、血糖,进行糖耐量试验.取血制血清,取出胰腺于4％多聚甲醛中固定.测定血清中胰岛素浓度,丙二醛(MDA)、总抗氧化力( T-AOC),所取胰腺做病理切片,观察胰岛细胞的变化.结果 Ovx组血糖和MDA值明显高于Sham组,总抗氧化力低于Sham组;Ovx+STZ血糖和MDA值高于Sham+STZ组,胰岛素水平和T-AOC要低于Sham+STZ组.结论 内源性雌激素对糖尿病小鼠具有一定保护作用.     

不同剂量链脲佐菌素对小鼠胰岛结构和主要细胞组成影响的研究

目的观察不同剂量STZ诱导的糖尿病小鼠模型中胰岛结构和细胞组成的变化。方法16只雄性C57BL/6小鼠随机分为4组,分别给予125(125STZ组)、150(150STZ组)及175(175STZ组)mg/kg STZ或柠檬酸缓冲液腹腔注射,动态监测体重、血糖、胰岛素及胰升血糖素水平,免疫荧光染色分析胰岛的形态结构和细胞数量。结果与对照组相比,3个剂量STZ均可引起小鼠体重下降(P=0.002),FBG升高(P0.001),各组随机血糖均≥16.7mmol/L。不同剂量STZ注射后小鼠血浆胰岛素水平下降,且呈剂量依赖性(P=0.027);而胰升血糖素水平则无明显变化。免疫荧光分析显示,不同剂量STZ注射后,小鼠胰岛体积均明显缩小,存在不同程度的β细胞残留。175STZ组α细胞数量较其他两个剂量STZ组增多,甚至超过对照组(P0.001)。各组δ细胞和PP细胞数量比较,差异无统计学意义。结论上述3个剂量STZ均可造成小鼠糖尿病模型,但胰岛结构、α及β细胞数量存在较大差别。     

Exendin-4通过上调pdx-1mRNA表达促进STZ造模小鼠β细胞增生

目的观察腹腔内注射exendin-4对链脲佐菌素(STZ)造模小鼠的血糖、胰岛数目和pdx-1表达的影响。方法C57BL/6小鼠30只被分成3组注射用水组、STZ50mg/kg 注射用水组和STZ50mg/kg exendin-40.1μg/g体重组。实验第1~10d每日腹腔内注射注射用水或exendin-4,实验第3~7d注射STZ。检测exendin-4注射期间和停药后血糖水平,停药后进行腹腔葡萄糖耐量试验(IPGTT)、胰腺胰岛计数和RT-PCR检测转录因子pdx-1的表达。结果STZ造模小鼠连续exendin-4注射期间平均血糖和注射用水组差异无统计学意义[(6.12±0.37vs6.21±0.41)mmol/L,P>0.05];而与未注射exendin-4的STZ小鼠组比较血糖明显降低[(6.12±0.37vs9.59±1.08)nmol/L,P<0.05];exendin-4停药后2周内的STZ exendin-4组的平均血糖仍较STZ 注射用水组明显降低[(13.02±1.96vs18.55±3.14)mmol/L,P<0.05]。IPGTT显示STZ exendin-4组的糖耐量较STZ 注射用水组明显改善,胰腺胰岛计数STZ exendin-4组较STZ 注射用水组增加了近1倍,转录因子pdx-1的表达也明显上调(P<0.05)。结论Exendin-4对STZ造模小鼠的血糖不仅具有短期控制作用,而且停药后仍有一定的维持作用。Exendin-4改善了STZ造模小鼠的糖耐量,上调了pdx-1的表达,促进了胰岛的增生。     

激动β_3肾上腺素受体对载脂蛋白E基因敲除小鼠胰腺血管紧张素受体表达的影响

目的探讨激动β3肾上腺素受体(β3-AR)对载脂蛋白E基因敲除(apoE-/-)小鼠血糖、胰岛素和胰腺血管紧张素Ⅱ受体(ATR)表达水平的影响。方法选用10周龄C57BL/6J小鼠10只为对照组(A组),另选10周龄apoE-/-小鼠50只,高脂饮食至36周龄时随机分为高脂模型组(B组)、阿托伐他汀阳性药物对照组(C组)、β3-AR激动剂小剂量组(D组)、β3-AR激动剂大剂量组(E组)和β3-AR拮抗剂组(F组),干预12周。48周时检测小鼠血糖和胰岛素水平;采用实时定量PCR和Western blot检测各组小鼠AT1R和AT2R表达水平。结果与A组比较,B组血糖、胰岛素明显升高,AT1R明显上调,AT2R明显下调(P<0.01);与B组比较,D组、E组血糖、胰岛素明显降低,AT1R明显下调,AT2R明显上调(P<0.01)。结论长期应用β3-AR激动剂通过下调apoE-/-老年高脂小鼠胰腺AT1R表达和上调AT2R表达,β3-AR与AT1R和AT2R存在交互作用,且与改善糖代谢紊乱有关。     

α-硫辛酸对链脲菌素诱发的大鼠胰岛β细胞损伤的保护作用

目的 研究α-硫辛酸(ALA)对链脲菌素(STZ)诱导的糖尿病大鼠胰岛β细胞损伤的保护作用.方法 30只SD大鼠按数字随机法分为正常对照组(NC组)、STZ组和ALA+STZ组(ALA组),各10只.后2组以STZ(70 mg/kg体重)一次性腹腔内注射诱发糖尿病,ALA组在注射前8 d开始给予ALA(50 mg·kg-1·d-1,强饲)直至实验结束(4周).STZ注射后每3天监测血糖、体重一次.测定胰腺匀浆中丙二醛(MDA)含量及还原型谷胱甘肽(GSH)水平,免疫组化方法检测胰岛β细胞内胰岛素水平.结果 STZ使大鼠血糖明显升高,STZ和ALA组制模成功率分别为90%(9/10)和70%(7/10),相差显著(P<0.05).实验结束时NC组、STZ组和ALA组平均体重分别为(368±3)g、(301±2)g和(341±26)g,3组间相差显著(P<0.05).STZ组胰腺组织内MDA水平为(1.22±0.14)nmol/mg prot,NC组为(0.57±0.04)nmol/mg prot,相差显著(P<0.05);STZ组胰腺组织内GSH含量为(16.54±1.10)mg/g prot,NC组为(25.46±0.62)mg/g prot(P<0.05);STZ组胰岛细胞呈退行性变.ALA组血糖较STZ组明显降低(P<0.05),胰腺组织匀浆MDA含量为(0.72±0.23)nmol/mg prot,较STZ组明显降低(P<0.05),GSH含量为(35.33 4±2.66)ms/s prot,较STZ组明显升高(P<0.05),胰岛的胰岛素分泌增强,较STZ组显著(P<0.05),胰岛β细胞损伤减轻.结论 ALA可通过减轻氧化应激来保护胰岛β细胞结构和功能的完整性.     

红花油对肥胖小鼠脂肪组织肥胖相关基因表达的影响

将70只C57BL/6小鼠分为对照组、猪油组、猪油改用红花油组和红花油组,第20周末取小鼠的脂肪组织作基因芯片检测.结果显示,猪油组小鼠的体重、血糖、血脂和血胰岛素较对照组明显升高(均P＜0.05).改喂红花油后小鼠体重、血糖、血脂和血胰岛素明显降低(P＜0.05)；红花油可调节脂肪组织的增食欲基因、厌食基因和能量消耗基因,如阿片受体、胰升糖素和PPARα等.     

2型糖尿病动物模型KK-Ay小鼠糖尿病肾病的鉴定

目的 研究2型糖尿病KK-Ay小鼠糖尿病肾病(DN)的特点和应用价值.方法 选择雄性KK-Ay小鼠和C57BL/6J小鼠各30只,每两周代谢笼收集24 h尿液及随意尿测尿微量白蛋白,眶后静脉丛采血测空腹血胰岛素、糖化血红蛋白、血糖、胆固醇、甘油三酯、尿素氮、肌酐、白蛋白.8、12、20周龄时两组分别处死10只小鼠取肾脏行病理检查.结果 不同周龄KK-Ar小鼠尿微量白蛋白、血胰岛素、糖化血红蛋白、血糖、胆固醇、甘油三酯均比同周龄C57BL/6J小鼠高(P＜O.05),且随周龄增加而进展,8周龄表现为典型2型糖尿病,12周龄进入早期DN,20周龄肾脏病理表现为特征性DN改变,但未见肾功能下降.结论 KK-Ay小鼠是研究DN早期病变的理想模型.     

六味地黄丸对自发性2型糖尿病模型小鼠肝、肾和胰腺组织学变化的影响

目的探讨不同剂量六味地黄丸对自发性2型糖尿病(T2DM)模型小鼠肝脏、肾脏和胰腺组织学变化的影响。方法将6~8周龄自发性T2DM模型小鼠(KK-Ay小鼠)随机分为无药对照组、低剂量组和高剂量组,C57BL/6J小鼠作为遗传对照组。各组小鼠分别给予蒸馏水或六味地黄丸灌胃15 w。给药15 w后,HE染色观察小鼠肝脏、肾脏和胰腺组织学变化。结果给药组小鼠肝脏、肾脏和胰腺组织病变明显减轻。低剂量组对小鼠肝脏的保护效果优于高剂量组;高剂量组对肾脏病变的治疗效果好于低剂量组;低剂量组对胰岛内胰岛细胞具有明显的保护作用。结论六味地黄丸对自发性T2DM所致的实验小鼠肝脏、肾脏和胰腺组织病理性改变具有明显的改善作用,且与给药剂量相关。     

C57BL/6J小鼠慢性应激形成过程中血细胞变化特点

目的 观察C57BL/6J小鼠慢性应激形成过程中血细胞的变化特点.方法 将20～25 g雄性C57BL/6J小鼠分成应激组及对照组.应激组小鼠独笼饲养,将6个日相和6个夜相刺激及一个全天刺激随机安排到1 w内,每周刺激顺序随机重新组合,连续8 w.对照组动物每5～6只小鼠合笼饲养,自由给水,整个实验过程中不接受任何刺激.两组动物均于刺激后的1、2、4、8 w经内眦取血,用于空腹皮质醇含量、血细胞计数及白细胞分类的检测.结果 与对照组相比较,应激组小鼠各时间点血浆皮质醇含量均明显高于对照组(P<0.01).刺激后的2、4、8 w应激组小鼠红细胞及血红蛋白含量均低于对照组(P<0.05或P<0.01),刺激后4和8 w应激组小鼠白细胞均低于对照组(P<0.01);而血小板计数和白细胞分类刺激后各时间点应激组与对照组无显著差异.结论 复合式慢性应激刺激可成功引起C57BL/6J小鼠处于应激状态,对C57BL/6J小鼠血细胞生成造成一定的影响.     

A potential role for skeletal muscle caveolin-1 as an insulin sensitivity modulator in ageing-dependent non-obese type 2 diabetes: studies in a new mouse model

Aims/hypothesis Type 2 diabetes mellitus is a common age-dependent disease. We discovered that male offspring of non-diabetic C57BL/6 and DBA/2 mice, called JYD mice, develop type 2 diabetes when they grow old. JYD mice show characteristics of insulin resistance, hyperglycaemia and hyperinsulinaemia in old age without obesity. We postulated that the mechanism of age-dependent type 2 diabetes in this model relates to caveolin-1 status in skeletal muscle, which appears to regulate insulin sensitivity in the mice. Methods We compared insulin sensitivity in aged C57BL/6 and JYD mice using glucose and insulin tolerance tests and ¹⁸F-fluorodeoxyglucose positron emission tomography. We also determined insulin signalling molecules and caveolin proteins using western blotting, and altered caveolin-1 levels in skeletal muscle of C57BL/6 and JYD mice using viral vector systems, to examine the effect of this on insulin sensitivity. Results In 30-week-old C57BL/6 and JYD mice, the basal levels of IRS-1, Akt and peroxisome proliferator-activated receptor-γ decreased, as did insulin-stimulated phosphorylation of Akt and insulin receptor β. However, caveolin-1 was only increased about twofold in 30-week-old JYD mice as compared with 3-week-old mice, whereas an eightfold increase was seen in C57BL/6 mice. Downregulation of caveolin-1 production in C57BL/6 mice caused severe impairment of glucose and insulin tolerance. Upregulation of caveolin-1 in aged diabetic JYD mice significantly improved insulin sensitivity with a concomitant increase of glucose uptake in the skeletal muscle. Conclusions/interpretation The level of skeletal muscle caveolin-1 is correlated with the progression of age-dependent type 2 diabetes in JYD mice. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users. Y. S. Oh and L.-Y. Khil contributed equally to this study. J.-W. Yoon passed away on 6 April 2006.     

Differential glycemic effects of morphine in diabetic and normal mice

C57BL/6J ob/ob mice, C57BL/6J+/? lean mice and A/J mice were given injections of 10 mg/kg of morphine or an equal volume of saline, and then blood was sampled by retroorbital sinus puncture. In addition, animals from each strain were exposed to a brief experimental stress ten minutes after the administration of morphine or saline. While morphine produced significant increases in serum glucose in albino mice, morphine lowered blood insulin in both C57BL/6J ob/ob and C57BL/6J+/? mice. Morphine significantly lowered blood insulin in A/J mice, but effects in C57BL/6J mice were not significant. In contrast, morphine attenuated blood glucose and insulin during stress in C57BL/6J ob/ob but did not significantly affect either glucose or insulin during stress in lean C57BL/6J or A/J mice. These results are interpreted in the light of other data suggesting that endogenous opiates modulate the effects of sympathetic nervous system activity in type II diabetes.     

二甲双胍促进2型糖尿病小鼠支链氨基酸分解代谢

目的 通过观察二甲双胍（Met）对高脂联合链脲佐菌素（STZ）诱导的2型糖尿病（T2DM）小鼠支链氨基酸（BCAAs）分解代谢作用并探讨其作用机制。 方法 通过高脂饮食+注射小剂量链脲佐菌素（STZ）途径构建T2DM小鼠模型。经随机分组,将20只C57BL / 6J雄性小鼠归入下述四组:正常对照组,2型糖尿病（T2DM）组,T2DM+安慰剂（T2DM+Vehicle）组,T2DM+二甲双胍治疗（T2DM+MET）组。高效液相色谱-串联质谱法检测小鼠血浆中的BCAA水平。实时荧光定量PCR检测小鼠心脏、肝脏和骨骼肌中BCAA分解代谢相关分子mRNA水平。Western Blot方法检测限速酶支链α-酮酸脱氢酶（BCKDH）活性,即P-BCKD / BCKD的水平。 结果 与正常对照组相比,T2DM小鼠的血浆BCAA水平明显升高（P<0.05）;BCKDH酶活性显著降低（P<0.05）;BCAA分解代谢相关分子mRNA水平显著降低（P<0.05）。二甲双胍治疗的T2DM小鼠血浆BCAA含量显著降低（P<0.05）,促进BCAA分解代谢的相关分子的mRNA水平显著提高（P<0.05）,BCKDH活性显著提高（P<0.05）。 结论 二甲双胍治疗可纠正T2DM小鼠血浆BCAA水平,为临床治疗BCAA代谢异常相关疾病提供了新思路。     

Increased hepatic expression of ganglioside-specific sialidase, NEU3, improves insulin sensitivity and glucose tolerance in mice

Membrane microdomains rich in gangliosides are recognized as being critical for proper compartmentalization of insulin signaling. Plasma membrane-associated sialidase, NEU3, is a key enzyme for ganglioside hydrolysis. We previously reported that mice overexpressing NEU3 mainly in muscles developed severe insulin-resistant diabetes. To examine the possible contributions of NEU3 to in vivo insulin sensitivity and glucose tolerance, NEU3 was expressed by using adenoviral vectors in the livers of C57BL/6 mice on standard and high-fat diets, and insulin-resistant KKAy mice on standard diets. Hepatic NEU3 overexpression paradoxically improved glucose tolerance and insulin sensitivity in the C57BL/6 mice fed standard diets, and glucose tolerance in the C57BL/6 mice fed high-fat diets and in KKAy mice. Hepatic NEU3 overexpression increased hepatic glycogen deposition and triglyceride accumulation, and enhanced the hepatic peroxisome proliferator-activated receptor gamma and fetuin expression in the C57BL/6 mice on standard and high-fat diets, and in KKAy mice. Thin-layer chromatographic analysis demonstrated increased levels of GM1 and markedly reduced GM3 in the livers of mice with hepatic NEU3 overexpression (NEU3 mice). Basal and insulin-stimulated tyrosine phosphorylations of insulin receptor substrate 1 were significantly increased, but tyrosine phosphorylations of the insulin receptor and insulin receptor substrate 2 in the NEU3 liver were unchanged. Insulin-stimulated tyrosine phosphorylations of the insulin receptor were increased in adipose tissues of NEU3 mice. These results suggest that hepatic NEU3 overexpression improves insulin sensitivity and glucose tolerance through modification of ganglioside composition and peroxisome proliferator-activated receptor gamma signaling. Our findings also provide further evidence that NEU3 is an important regulator of insulin sensitivity and glucose tolerance.     

胰岛素B链基因疫苗的构建及其对小鼠自身免疫性糖尿病的干预预防

目的 应用构建胰岛素B链基因疫苗预防自身免疫性糖尿病。方法 采用逆转录聚链反应（RT-PCR）等技术,构建胰岛素B链基因疫苗,将该疫苗注射入胰岛素B链基因疫苗治疗组（T组）和胰岛素B链基因疫苗预防组（P组）小鼠胫前肌内。定时测定小鼠血糖、胰岛素水平。于第四周观察小鼠胰腺组织病理形态的改变,与对照组（C组）和糖尿病组（D组）进行比较。结果 （1）运用RT-PCR扩增技术,克隆胰岛素B链基因,构建成胰岛素B链基因疫苗。（2）在有糖尿病发病倾向小鼠发病前注射胰岛素B链基因后,其发病例数第2周为3只（3/10）,第3、4周为4只（4/10）,显著低于D组和T组;P组内预防有效者血中胰岛素水平与C组相比差异无显著性。而糖尿病未缓解的小鼠病理变化和D组相似。结论 构建胰岛素B链基因疫苗可以有效地预防自身免疫性糖尿病的发生,为1型糖尿病干预预防开辟了新的途径。     

四氢姜黄素对2型糖尿病小鼠糖脂代谢及大血管病变的影响

目的 探讨四氢姜黄素（THC）对2型糖尿病(T2MD)小鼠糖脂代谢的影响及其血管的保护作用。 方法 60只体质量（20~25）g雄性C57BL/6J小鼠,随机取15只小鼠作为正常对照（Con）组,正常饮食,其余小鼠均以高糖脂饮食结合小剂量连续腹腔注射链脲佐菌素(STZ)的方法建立T2MD小鼠模型。造模成功后随机分为模型（T2MD）组和治疗（T2MD+THC）组,治疗组给THC药12周。实验结束后,检测血清总胆固醇（TC）、甘油三酯（TG）、血清葡萄糖（GLU）、高密度脂蛋白胆固醇（HDL-C）及低密度脂蛋白胆固醇（LDL-C）含量;取小鼠主动脉观察其病理形态学改变,Western blot法检测Notch1信号关键分子NICD、氧化应激标志分子gp91phox、平滑肌表型标志分子α-SMA的表达水平。 结果 与模型组比较,THC治疗组可以显著改善T2MD小鼠糖脂代谢异常,主动脉组织中NICD表达升高、gp91phox明显降低、α-SMA上调,血管形态得到明显改善(P<0.05)。 结论 THC可以明显改善T2MD小鼠糖脂代谢异常,并发挥大血管保护作用,其可能机制是否通过Notch1信号通路调节氧化应激损伤进而保护血管有待进一步研究。     

Roles of interleukin 17 in angiotensin II type 1 receptor-mediated insulin resistance

Interleukin 17 (IL-17) is known to contribute to the pathogenesis of hypertension, atherosclerosis, and adipocyte differentiation; however, the roles of IL-17 in glucose metabolism remain to be elucidated. Angiotensin II type 1 receptor blockers improve insulin resistance at least in part because of the amelioration of inflammation. Therefore, we examined the possible roles of IL-17 in the pathogenesis of insulin resistance in type 2 diabetes mellitus using a mouse model, KK-Ay, and angiotensin II type 1 receptor-mediated insulin resistance. KK-Ay mice were administered control-IgG(2A) or anti-IL-17 antibody 5 times at a dose of 100 μg every second day by IP injection. KK-Ay mice were administered telmisartan for 2 weeks. C57BL/6J mice treated with angiotensin II infusion for 2 weeks were administered telmisartan or hydralazine. Insulin resistance was evaluated by oral glucose tolerance test, insulin tolerance test, and uptake of 2-[(3)H]deoxy-d-glucose in peripheral tissues. Serum IL-17 concentration in KK-Ay mice was significantly higher than that in C57BL/6J mice. Treatment of KK-Ay mice with anti-IL-17 antibody significantly increased 2-[(3)H]deoxy-d-glucose uptake in skeletal muscle but not in white adipose tissue and attenuated the increase in blood glucose level after a glucose load. Blockade of IL-17 enhanced the expression of adipocyte differentiation markers and adiponectin. Treatment with telmisartan decreased serum IL-17 concentration in KK-Ay and ameliorated angiotensin II-induced insulin resistance with a decrease in serum IL-17 level in C57BL/6J. In conclusion, IL-17 could play an important role in the pathogenesis of angiotensin II type 1 receptor-induced insulin resistance.     

Genetic susceptibility to diabetes in inbred strains of mice: measurements of proinsulin mRNA and response to dexamethasone

Summary The insulin resistance produced by the recessive db mutation has led to more severe diabetes in C57BL/KsJ mice relative to that in C57BL/6J mice, suggesting genetic differences between the two strains affecting insulin production or insulin action. To assess these parameters blood glucose, serum insulin, pancreatic insulin, and proinsulin mRNA were measured in both normal and diabetic (db/db) KsJ and 6J strains. The mice were compared at 5 weeks of age, prior to the development of insulin lack known to occur with age in KsJ db/db mice. As a further provocation to insulin production, another group of the normal and db/db mice were given dexamethasone for 4 days. In normal mice there were no strain differences in blood glucose, serum insulin, pancreatic insulin, or proinsulin mRNA. Dexamethasone, presumably by augmenting insulin resistance, induced increases in serum insulin and proinsulin mRNA to the same extent in KsJ and 6J mice. In db/db mice, while blood glucose, serum insulin, and proinsulin mRNA were considerably higher than in normal mice, there were no strain differences observed. After dexamethasone the db/db mice exhibited strain differences which included higher blood glucose and higher serum insulin levels in KsJ mice. These findings were compatible with greater insulin resistance in KsJ than in 6J db/db mice. While dexamethasone treatment increased serum insulin in KsJ db/db mice, there was no augmentation of proinsulin mRNA in either strain, suggesting a limit to the insulin synthesis. Analysis of serum insulin/glucose and proinsulin mRNA/glucose ratios demonstrated a dexamethasone-induced increase in serum insulin/glucose in normal and diabetic mice of both strains. An increase in dexamethasone induced proinsulin mRNA/glucose ratio was observed in all but the KsJ db/db mice. This analysis suggested that although insulin secretion in KsJ db/db mice was augmented, the capacity for insulin synthesis had been exceeded. A limitation of insulin production at the level of insulin synthesis might explain the enhanced diabetes susceptibility of this strain.