实验性链脲佐菌素糖尿病

链脲佐菌素(streptozotocin,Stz)为一广谱抗菌素,具有抗菌、抗肿瘤的性能和致糖尿病的副作用。1963年Rakieten等报道,Stz对实验动物的胰岛β细胞具有高度选择性毒性     

链脲佐菌素致动物胰岛的组织学变化

链脲佐菌素（STZ）对实验动物的胰岛B细胞具有高度选择性毒性作用,目前已较多使用STZ来建立糖尿病动物模型。本文拟就STZ致动物胰岛的组织学变化作一综述。     

链脲佐菌素小鼠糖尿病胰岛结构改变的定量病理学测试及分析

目的:定量揭示链脲佐菌素（Streptozotocin, STZ）诱发的小鼠糖尿病胰岛结构改变的特点,为分析胰岛功能改变补充定量病理学基础。方法:腹腔注射STZ,诱发Balb/c小鼠糖尿病;过量CO2处死小鼠并取胰腺,常规病理制样、胰岛素免疫组化染色、图像测试及定量分析。结果:造模第8周,糖尿病组（DM组）小鼠血糖显著高于正常对照组（NC组）小鼠,DM组小鼠血糖均值为19.3 mmol/L;相比NC组小鼠,DM组小鼠胰岛数目、β细胞数目及面积显著减少（P<0.05）,计算得出β细胞数量丧失约62.7％,胰岛β细胞面积丧失约27.0%,胰岛素阳性单位（PU值）表达减少约53.8％。DM组小鼠胰岛β细胞面积密度（AAβ,PI）、面数密度（NAβ,PI）、数量百分比（βPer）均显著降低（P<0.05）,其中PU值、AAβ,PI、βPer与血糖升高呈负相关,皮尔森相关系数（R值）分别为-0.653、-0.736和-0.899（显著性均<0.05）;建立造模时间（t）与胰岛β细胞数量百分比改变的函数:[βPer(%)=79.68-9.74t+0.38t2+0.06t3-4.66×10-3t4+2.86×10-5t5+1.68×10-5t6]。结论:通过定量病理学技术测量糖尿病小鼠模型胰岛和β细胞形态学改变的相关指标,能够帮助准确评估胰岛的损伤情况,并建立血糖变化和所测量数值的相关数学模型,用以预测血糖升高导致胰岛损伤的具体情况。 【关键词】糖尿病;胰岛;定量病理学;阳性单位;链脲佐菌素     

链脲佐菌素敏感的胰岛细胞表达亨廷顿蛋白相关蛋白1

目的探讨亨廷顿蛋白相关蛋白1（HAP1）在大鼠胰岛中的定位.方法应用一次性大剂量腹腔注射链脲佐菌素（streptozotocin）的方法选择性破坏大鼠胰岛B细胞复制糖尿病模型,免疫组织化学ABC法显示胰岛内HAP1和胰岛素免疫反应性.结果在正常大鼠胰腺内,HAP1选择性表达于胰岛内,HAP1免疫反应阳性细胞呈短条索状或团状分布在每个胰岛内,主要位于胰岛的中央部,与胰岛B细胞的分布十分相似.注射链脲佐菌素的大鼠,胰岛中含HAP1的细胞数量在注射链脲佐菌素3d后已明显减少,并随着注射后动物存活时间的延长而进一步进行性减少;在注射后4周的大鼠,胰岛中仅有少数散在分布的HAP1免疫反应弱阳性细胞.链脲佐菌素对胰岛中表达HAP1细胞的影响与对表达胰岛素细胞的影响一致.结论HAP1也存在于胰岛内,并主要定位于链脲佐菌素敏感的B细胞内.     

实时FQ-PCR检测链脲佐菌素诱导糖尿病小鼠模型胰腺survivin基因的表达

目的：研究链脲佐菌素（STZ）诱导的糖尿病小鼠胰腺survivin基因mRNA表达，了解其在胰岛损伤中的作用。 方法： 小剂量多次注射STZ的方法建立糖尿病小鼠模型，每周测定体重及血糖，并采用实时荧光PCR方法检测胰腺survivin基因mRNA表达水平。 结果： 正常BALB/c小鼠胰腺有survivin基因表达。STZ组体重在4周内无明显改变；血糖在第1周即明显升高；survivin表达水平在3、4周显著升高。对照组体重持续增加，血糖及survivin表达水平各周间无显著差异。 结论： 正常小鼠胰腺有survivin基因表达，STZ注射后survivin表达水平显著升高，可能与胰岛恢复有关。     

链脲佐菌素诱导MSG大鼠糖尿病心脏病模型的研究

目的:探讨腹腔注射链脲佐菌素(Streptozotocin,STZ)诱导L-谷氨酸钠(Monosodium glutamate,MSG)肥胖大鼠建立糖尿病心脏病模型。方法:选用新生SD大鼠随机分为两组:MSG组和正常对照组(NS组)。MSG组新生大鼠自出生第2d起颈部皮下注射L-谷氨酸钠5g·kg-1,隔天一次,共三次;正常对照组于皮下注射等体积无菌注射用水。MSG组于6周龄时再随机分为4个小组,腹腔注射链脲佐菌素0mg·kg-1,20mg·kg-1,30mg·kg-1,40mg·kg-1。于注射STZ 4w后测定各心脏血流动力学相关指标,同时取血测定其胰岛素水平及血液脂质等指标。结果:注射STZ 4w后,MSG组大鼠Lee’s指数显著增加,心脏指数明显降低,血浆高密度胆固醇(HDL)、低密度胆固醇(LDL)升高,收缩压(SBP)、舒张压(DBP)、平均动脉压(MAP)、心率(HR)、左心室收缩压(LVSP)、左心室内压最大上升速率(+dp/dt)、下降速率(-dp/dt)均显著升高,心电图显示其Q-T间期缩短,与对照组比较有统计学差异。MSG+STZ 30mg·kg-1组大鼠SBP、DBP、MAP、HR、+dp/dt、-dp/dt均显著降低,与MSG组比较有统计学差异。MSG+STZ 40mg·kg-1组大鼠SBP、DBP、MAP、HR、LVSP、+dp/dt、-dp/dt均显著降低,Lee’s指数降低,胰岛素浓度降低,血糖水平及心脏指数升高,血浆LDL水平降低,Q-T间期延长,与MSG组比较有统计学差异。结论:研究表明MSG大鼠在6周龄时腹腔注射STZ 40mg·kg-1,有利于糖尿病心脏病模型的建立,为研究、开发防治2型糖尿病心脏病的新药提供了一种良好的动物模型。     

海马sortilin在链脲佐菌素诱导的糖尿病认知损伤小鼠中的作用

目的 探讨海马sortilin在链脲佐菌素（STZ）诱导的糖尿病认知损伤小鼠中的作用。方法 24只成年雄性ICR小鼠,随机分为溶媒对照组（NS）和实验组（STZ）。STZ腹腔注射诱导糖尿病认知损伤动物模型,注射后用血糖仪检测血糖改变,注射后第8周采用新旧事物识别实验检测各组小鼠认知功能;免疫组织化学方法检测sortilin免疫阳性产物表达变化;Western blotting和Real-time PCR方法检测各组小鼠海马sortilin和脑源性神经营养因子（BDNF）蛋白及mRNA表达变化。结果 与NS组相比,STZ组小鼠空腹血糖显著增高（P<0.01）;在新旧事物识别实验中新事物辨别指数明显降低（P<0.05）;海马区sortilin的免疫阳性产物（P<0.05）、蛋白（P<0.01）以及mRNA（P<0.05）表达均显著下调;海马区BDNF mRNA（P<0.01）及蛋白（P<0.05）表达均明显降低。结论 STZ诱导的糖尿病小鼠认知损伤可能与海马sortilin的表达下调有关。     

链脲佐菌素对糖尿病小鼠生精功能和睾丸m6A甲基化酶表达的影响

目的 探讨链脲佐菌素（streptozotocin,STZ）对糖尿病小鼠生精功能和睾丸m6A甲基化酶表达的影响。方法 20只8周龄雄性ICR小鼠,随机分为溶媒对照组和模型组,腹腔注射STZ诱导糖尿病动物模型。注射后第2、4、6、8周检测血糖及体重;第8周采用精子计数法检测小鼠精子数量,HE染色检测精子存活率及睾丸形态,称量睾丸、附睾的重量;Real-time PCR和Western blotting检测各组小鼠睾丸中m6A甲基化酶mRNA及蛋白表达。结果 与对照组相比,模型组小鼠空腹血糖显著增高,体重降低（P<0.01）;睾丸及附睾重量显著下降（P<0.01）、精子数量显著下降（P<0.05）;睾丸形态结构破坏,生精小管萎缩,管腔直径变小,各级生精细胞排列紊乱,管腔内精子数量减少;睾丸m6A甲基化酶METTL3、FTO、YTHDF3 mRNA表达降低（P<0.05）;METTL3、FTO蛋白质表达显著降低（P<0.05）。结论 STZ诱导的糖尿病小鼠出现生精障碍,其生精障碍可能与睾丸内m6A甲基化酶METTL3以及FTO的表达异常有关。     

DNA甲基转移酶1在乳腺癌患者中的表达及意义

目的:分析乳腺癌患者外周血中DNA甲基转移酶1(DNA Methyltransferase 1,DNMT1)的表达及其临床意义。方法:本院2018-04-01—2018-11-30期间收治的60例乳腺癌患者(实验组)及同期50例体检健康女性(对照组),采用实时定量PCR(RT-PCR)检测外周血中DNMT1 mRNA的表达情况,Western blot检测两组间DNMT1蛋白表达,比较两组间各指标的差异并分析其与患者临床特征的关系。结果:实验组DNMT1 mRNA在外周血中的表达较对照组显著升高(10.31±3.39 vs 4.74±3.10,P<0.01),DNMT1蛋白表达较对照组亦显著升高(38.48±3.80 vs 23.78±2.95,P<0.01);不同临床特征乳腺癌患者外周血中DNMT1 mRNA和蛋白表达差异无统计学意义(P>0.05)。结论:DNMT1在乳腺癌患者外周血中高表达,与乳腺癌发生密切相关,但与其发展转移无关。     

Immunolocalization of 8-OHdG and OGG1 in pancreatic islets of streptozotocin-induced diabetic rats

This study examined whether oxidative DNA damage and its repair system contribute to the occurrence of diabetes in an experimental rat model. The changed morphological findings of the 8-hydroxydeoxyguanosine (8-OHdG) and 8-oxoG-DNA glycosylase (OGG1) were examined in the pancreatic islets in streptozotocin-induced diabetic rats (60 mg/kg, i.p.). The patterns of immunolocalization were mainly observed in the periphery of the normal pancreatic islet: 8-OHdG in the nucleus and OGG1 in the cytoplasm. The altered immunolocalization of 8-OHdG and OGG1 were greatest in the first hours after streptozotocin injection, and then declined in parallel with the morphological observations of pancreatic beta cell destruction. These results suggested that increased oxidative DNA damage might play a role as the inducer of diabetes and that OGG1 may not successfully mediate DNA repair in streptozotocin-induced diabetic rat pancreas.     

糖尿病小鼠肾小球微血管密度与VEGF表达的研究

目的: 探讨糖尿病小鼠肾小球微血管密度(MVD)变化及其与血管内皮生长因子(VEGF)表达的关系。方法: 链脲佐菌素诱导小鼠糖尿病6周,定期测量对照组与模型组小鼠体重与血糖变化;常规HE染色观察肾脏形态学变化,采用组织细胞病理分析软件测量肾小球直径、周长及面积;应用免疫组织化学方法检测CD34及VEGF在肾小球的表达,计算MVD值及VEGF表达指数。结果: 与对照组相比,模型组小鼠血糖明显升高(P＜0.01),体重显著降低(P＜0.01),肾小球直径、周长及面积明显增大(P＜0.05);肾小球CD34及VEGF表达明显增强(P＜0.01),肾小球MVD显著增高且与VEGF表达呈显著正相关(r=0.9979,P＜0.05)。结论: VEGF可促进糖尿病小鼠肾小球新生血管生成,VEGF表达上调与糖尿病肾脏病变密切相关。     

葛根素对糖尿病大鼠心肌损伤的影响

目的:探讨葛根素对糖尿病大鼠心肌损伤的影响及其机制。方法:雄性SD大鼠随机分成6组:正常对照组,糖尿病模型组,葛根素高(160mg·kg-1)、中(120mg·kg-1)、低(80mg·kg-1)剂量治疗组,氨基胍(100mg·kg-1)治疗组;各组大鼠每天腹腔注射相应药物1次,正常对照组及糖尿病模型组腹腔注射等体积丙二醇。治疗12周后,透射电镜下观察心肌的形态学改变,用生化方法测定血糖浓度、心肌组织中超氧化物歧化酶(SOD)、Ca2+-ATPase、Na+-K+-ATPase活性及丙二醛(MDA)含量,采用RT-PCR检测心肌组织过氧化物酶体增殖物激活受体γ(PPAR-γ)、葡萄糖转运体4(GLUT-4)、醛糖还原酶(AR)的mRNA表达水平。结果:糖尿病组大鼠心肌组织电镜下主要见到心肌细胞肌原纤维减少,纤维间脂滴沉积,线粒体排列紊乱,嵴部分断裂或消失,结构不清;SOD、Ca2+-ATPase、Na+-K+-ATPase活性和PPAR-γ、GLUT-4 mRNA表达明显低于正常对照组(均P0.01),而血糖浓度、MDA含量和AR mRNA表达明显高于正常对照组(均P0.01)。经葛根素治疗后,上述改变逆转,与糖尿病模型组比较差异显著(P0.05或P0.01),电镜下心肌组织形态学病变明显减轻,肌纤维排列较整齐,仅见少量脂滴沉积,大部分线粒体嵴清晰致密。结论:葛根素对糖尿病大鼠心肌具有一定的保护作用,其机制可能与上调PPAR-γ、GLUT-4 mRNA的表达,促进心肌细胞对葡萄糖的摄取,减轻氧化应激损伤有关。     

STZ诱导糖尿病大鼠肾脏CTGF表达改变及意义探讨

目的：观察STZ诱导糖尿病大鼠肾脏结缔组织生长因子(CTGF)表达改变及意义。方法:将SD大鼠分为对照(假手术)组(C组)（n=32）、糖尿病肾病组(DN组)（n=35）2组。每组再随机分为4个亚组：1周、2周、4周和8周组。观察各组大鼠血糖（BG）、24 h尿量（UV）、体重（BW）、尿白蛋白排泄(24 Ualb)、内生肌酐清除率(Ccr)、肾重(KW)、肾重/体重(KW/BW)、肾小球面积(A_G)和体积(V_G)、近端小管面积(A_T)、GBM、TBM厚度的改变，免疫组化观察CTGF和α-SMA在小球、小管的表达情况。结果：实验期间DN组BG、UV明显大于C组（P<0.01），DN组24 h Ualb（mg/24 h）、Ccr、KW、 KW/BW、A_G、V_G、A_T、小球及小管的CTGF表达均持续显著高于C组，AT在4周时达到高峰，且CTGF表达与24 Ualb、A_G、V_G、A_T等指标呈显著正相关 (r分别=0.95、0.92、0.86、0.94, 分别P<0.01、 P<0.05)。α-SMA 在DN组大鼠早期肾小管上皮细胞中表达不明显，第4周起可见少量α-平滑肌肌动蛋白(α-SMA)表达，到第8周时更明显。8周时DN组GBM和TBM明显厚于C组 (P<0.01)。结论：糖尿病早期CTGF表达增加，并可能参与介导糖尿病早期肾脏肥大，CTGF可能与随后的肾小管上皮细胞转分化和肾脏纤维化有关。     

糖尿病在糖尿病大鼠心肌梗死后心力衰竭形成中的效应

目的： 评估糖尿病在链脲霉素（STZ）诱导的血糖不加控制的糖尿病大鼠急性心肌梗死（AMI）后心力衰竭(HF)形成中的效应。方法：所有SD大鼠随机分组,糖尿病组经腹腔内注射STZ（65mg/kg）诱导糖尿病,70 d后所有AMI组结扎冠状动脉左前降支建立AMI模型。确定AMI前后各时点观察大鼠的生存率,心肌超微结构的变化,进行血流动力学分析、心肌纤维化测定及左心肥厚的评估。结果：结扎左冠状动脉前降支后,糖尿病大鼠的左心功能恶化及左室重构的速度均较非糖尿病大鼠显著。在早期阶段,糖尿病与非糖尿病大鼠心肌纤维化相似,而1月后却出现显著差别。结论：糖尿病大鼠AMI后心力衰竭进展明显加速。     

The influence of cyclosporin A on the vascular permeability of the pancreatic islets and on diabetes induced by multiple low doses of streptozotocin in the mouse

Summary The aim of the present study was to investigate the influence of cyclosporin A on the course of multiple low dose streptozotocin induced diabetes in mice, an animal model for human type I diabetes mellitus. C57BL/Ks mice were treated on five consecutive days with intraperitoneal injections of steptozotocin or citiric acid buffer. Thirty min before the injections the animals were given cyclosporin A (10 or 50 mg/kg body weight) or saline. Cyclosporin A did not protect against the hypoglycaemia and at the higher dose it potentiated the diabetogenic effect. Furthermore, cyclosporin A did not affect the development of insulitis when the pancreatic glands were examined by light microscopy. Using a technique for monitoring vascular permeability in vivo with the aid of the pigment Monastral Blue B, it was found that the development of diabetes was accompanied by an increased vascular leakage. Control animals treated with cyclosporin A also showed an increased islet staining with Monastral Blue B. The data indicate that cyclosporin A potentiates diabetes induced by low doses of streptozotocin. This can be attributed to a direct toxic effect of cyclosporin A on the pancretic B-cells and may also be due to an increased vascular leakage induced by cyclosporin A. The latter would allow an increased migration of inflammatory cells into the islets and the consequent release of B-cytotoxic substances.This work was supported by grants from the Swedish Diabetes Association, the Swedish Medical Research Council (12X-109, 12X-8273; 12P-7680), the Clas Groschinsky Memorial Foundation, the Nordic Insulin Fund, the Ernfors Family Fund, the Swedish Society of Medicine and the Hoechst Diabetes Foundation     

Streptozotocin-induced type 1 and 2 diabetes in rodents: a model for studying diabetic cardiac autonomic neuropathy

BackgroundSeveral animal models are continually being developed to study diabetic complication. Several conflicting regimen for diabetes induction exist in the literature with varying dose strength and regimen for different study interest in diabetes. This study aims to show the effect of high dose streptozotocin (STZ) on the one hand compared with multiple low doses after high fat diet induction on diabetic cardiac autonomic neuropathy (DCAN).MethodologyEighty-four Wistar rats were used to demonstrate DCAN induction using 2 approaches one for T1DM (STZ 50mg/kg) and the other for T2DM (HFD for 8 weeks with STZ 25mg/Kg daily for five days). DCAN features were assessed using invasive biomarkers, histology patterns and cardiac nerve densities.ResultsDiabetes induction rate was 76% and 89% in T1DM and T2DM model respectively. T1DM group had significant weight loss, reduced c-peptide, and insulin level post induction. The T2DM additionally showed significantly higher total cholesterol and Homeostatic model assessment (HOMA) compared with control. Serum levels of catecholamine, choactase, nerve growth factor and cardiac nerve density confirms development of DCAN.ConclusionHigh single dose of STZ and HFD with multiple low doses of STZ may be recommended for DCAN study in T1DM and T2DM rat model respectively.     

Islet amyloid polypeptide in insulinoma and in the islets of the pancreas of non-diabetic and diabetic subjects

Summary Amyloid deposition is a common pathological feature in insulinoma and in the islets of the pancreas in type-2 diabetic patients. The present immunohisto-chemical study revealed that normal B-cells, insulinoma, and amyloid deposits in insulinoma and diabetic pancreatic islets were commonly immunoreactive with antiserum to C-terminal synthetic tetradecapeptide of human islet amyloid polypeptide (IAPP) (24–37). Amyloid fibrils in insulinoma were also positive to IAPP by immunoelectron microscopy. A high level of IAPP was detected in the plasma and tissue of a insulinoma patient by radioimmunoassay suggesting that amyloid deposition in insulinoma is due to overproduction of IAPP. Amyloid deposits immunoreactive to IAPP were also seen in all diabetic pancreatic islets, but in no non-diabetic islets. There was much amyloid deposition in the islets of severe diabetics, whose B-cells demonstrated decreased immunoreactivities for IAPP and insulin. The IAPP content of the pancreas was 649.0 and 847.7 pg/mg wet weight in each of two diabetic patients, and 1034.6 and 1447.7 pg/mg wet weight in two non-diabetic patients. The present study revealed that IAPP is a bioactive peptide secreted from islet B-cells and are amyloidogenic peptide concerned in diabetogenensis and/or the progression of type-2 diabetes mellitus.     

糖尿病大鼠肾脏细胞因子基因表达初步研究

目的:研究糖尿病大鼠肾脏细胞因子mRNA的表达。方法:大鼠随机分成2组:单肾切组、糖尿病组。实验第8周,应用RT-PCR技术检测大鼠肾皮质转化生长因子-β₁ (TGF-β₁)、血小板衍化生长因子-B(PDGF-B)、肿瘤坏死因子-α (TNF-α)及Ⅳ型胶原mRNA的表达。 结果: 糖尿病组大鼠肾皮质TGF-β₁ (P＜0.01)、 PDGF-B(P＜0.01)、TNF-α(P＜0.01)及Ⅳ型胶原(P＜0.01)mRNA的表达显著高于单肾切组大鼠。结论: 在实验性大鼠糖尿病肾皮质TGF-β₁、PDGF-B 、TNF-α和Ⅳ型胶原mRNAs表达显著增加。