阻断肾素血管紧张素系统通过下调iNOS改善糖尿病大鼠胰岛功能

目的 研究阻断肾素血管紧张素系统(RAS)对糖尿病大鼠胰岛功能的影响.方法 以高脂饮食结合小剂量腹腔注射链脲佐菌素(30 mg/kg)的方法建立糖尿病大鼠模型,分别以培哚普利4 mg·kg-1·d-1(AE组,n=10)和缬沙坦40 mg·kg-1·d-1(AR组,n=10)干预.8周后行静脉葡萄糖耐量试验检测胰岛β细胞功能,以RT-PCR检测胰岛血管紧张素原(AGT)和胰岛素mRNA的表达,以TUNEL法检测胰岛细胞凋亡,以免疫组化法检测胰岛局部诱导型NO合酶(iNOS)及细胞内胰岛素水平等.结果 与正常对照组(n=10)相比,糖尿病组(n=8)早期胰岛素分泌指数(EISI)降低了81.1%,胰岛AGT表达增加了69.2%,单位面积胰岛细胞凋亡计数增加了2.1倍,局部iNOS相对浓度增加了23.0%(均P＜0.01);培哚普利或缬沙坦干预后,EISI分别增加了1.84和1.74倍,胰岛AGT表达分别降低了21.4%和23.4%,胰岛凋亡细胞计数分别降低了79.0%和36.3%,局部iNOS相对浓度分别下降了16.5%和18.9%(均P＜0.01).AE、AR组之间差异无统计学意义.结论 阻断RAS可以改善糖尿病大鼠胰岛功能,其机制可能与下调胰岛局部iNOS表达,减弱氧化应激对胰岛的损伤有关.     

肾素-血管紧张素系统与2型糖尿病

组织局部存在肾素-血管紧张素系统（RAS）。RAS活化可加重外周组织胰岛素抵抗，并影响胰岛的形态与功能。其可能机制是影响交感神经活性、血流动力学、炎症反应、氧化应激以及王惠芳细胞增殖与凋亡等。通过使用血管紧张素转换酶抑制剂（ACEI）和血管紧张素Ⅱ受体阻断剂（ARBs）阻断RAS，可以改善胰岛素抵抗与胰岛功能，从而逆转糖耐量异常或改善糖代谢紊乱状态。     

缬沙坦与培哚普利治疗心肌梗死的疗效随访

目的 探讨缬沙坦与培哚普利对心肌梗死后心功能Ⅱ～Ⅳ级病人的保护作用。方法心肌梗死后心功能Ⅱ～Ⅳ级的病人分为缬沙坦组和培哚普利组,分别给予缬沙坦80～160 mg/d或培哚普利4～8 mg/d治疗。在19个月的中位随访期间,观察病死率和病残率的联合终点,测定血一氧化氮、内皮素和脑钠肽水平,用超声心动图评价心脏收缩功能和血生化改变。结果 缬沙坦组死亡4例（占7.7%）;培哚普利组死亡4例（占8.7%）,死因相似;与给药前比较,缬沙坦和培哚普利两组病人心脏功能有明显改善,血一氧化氮水平增高,内皮素和脑钠肽水平降低。与培哚普利组比较,缬沙坦组血一氧化氮和内皮素值的改变较大,差异有统计学意义（P＜0.05）。而血中脑钠肽的改变差异无统计学意义（P＞0.05）。结论 缬沙坦和培哚普利对心肌梗死后心肌均有保护作用。缬沙坦改变血一氧化氮和血浆内皮素水平优于培哚普利。     

缬沙坦对糖尿病大鼠内皮细胞功能及氧化应激的影响

以链脲佐菌素建立糖尿病大鼠模型,缬沙坦干预治疗12周,光镜下观察大鼠胸主动脉组织结构,并用RT-PCR方法测定血管紧张素II（AngII）mRNA表达平,用Elisa方法测定血清血管假血友病因子（VWF）、内皮素-1（ET-1）、8脱氧鸟酐（8-OHdG）、超氧化物歧化酶（SOD）含量。结果缬沙坦干预治后,8OHdG含量降低,SOD活性增加;ET-1、VWF含量均降低;光镜下观察大鼠胸主动脉病理损伤得到改善。结论氧化应激和肾素血管紧张素（RAS）系统的紊乱参与了糖尿病大鼠的胸主动脉病变过程,缬沙坦通过阻断RAS系统活性,下调AngII基因表达,降低氧化应激反应,从而减轻血管内皮细胞损伤,可能是缬沙坦保护胸主动脉内皮功能的基本机制之一。     

缬沙坦与培哚普利对高血压患者血管顺应性的影响

目的评价缬沙坦与培哚普利的降压疗效和对血管顺应性的影响。方法选择原发性高血压患者50例,起始随机应用缬沙坦80-160 mg治疗12周,然后停药2周;第14周改用培哚普利4-8 mg治疗。实验开始及治疗第12、26周测定脉搏波速度及血压。结果缬沙坦及培哚普利治疗均可降低患者血压、颈动脉—股动脉的脉搏波速度,但两种药物作用效果无统计学差异（P〉0.05）。缬沙坦可明显降低患者颈动脉—桡动脉的脉搏波速度、股动脉—足背动脉脉搏波速度,与培哚普利比较有统计学差异（P〈0.05）。结论缬沙坦与培哚普利都能够很好地控制血压及改善中央弹力动脉的顺应性,缬沙坦独立于控制血压作用之外对于肌性动脉有额外的改善作用。     

培哚普利在糖尿病大鼠肢体缺血后血管再生中的作用

目的探讨培哚普利在1型糖尿病（T1DM）大鼠肢体缺血后血管再生中的作用及相关机制。方法对T1DM大鼠模型予单侧肢体股动脉离断。分为对照（DM）组、培哚普利治疗（DMA）组和培哚普利＋内皮型一氧化氮合酶（eNOS）阻断剂治疗（DML）组。治疗4周后比较各组缺血肢体血管再生情况以及eNOS、血管内皮生长因子（VEGF）、碱性成纤维细胞生长因子（bFGF）的mRNA和蛋白表达水平。结果与正常对照（Nc）组相比,DM组的缺血肢体微血管密度（MVD）、eNOS、VEGF和bFGF的mRNA和蛋白表达均下降,DMA组上述指标明显上调（P均〈0．05）。DML组的MVD、eNOS和bFGF的mRNA和蛋白表达降低（P〈0．05）,而VEGF表达不受影响（P〉0．05）。结论T1DM大鼠的缺血性血管再生受损,与之有关的生长因子表达下调。培哚普利能促进T1DM大鼠缺血肢体的血管再生,其机制与eNOS、VEGF和bFGF的表达上调有关。     

血管紧张素（1～7）对2型糖尿病大鼠胰岛形态及功能的影响

目的：研究血管紧张素（1～7）[Ang（1～7）]对2型糖尿病（T2DM）大鼠胰岛形态及功能的影响。方法以高糖高脂饮食结合小剂量腹腔注射链脲佐菌素（40mg/Kg）的方法建立T2DM大鼠模型,随机分为糖尿病对照（D0）组、Ang（1～7）[300μg/（kg·d）]干预（D1）组,每组10只。D0组以等量的生理盐水颈部皮下注射,连续8周,仍以高糖高脂饲料喂养。8周后运用免疫组织化学染色法检测胰岛局部诱导型NO合酶（iNOS）及细胞内胰岛素的表达,并选择胰岛部分用计算机图像处理系统进行平均光密度检测,采用ELISA法检测血清空腹胰岛素（FINS）及血管紧张素Ⅱ（AngⅡ）含量,计算稳态模型胰岛素抵抗指数（HomaIR）。结果与正常对照组相比,D0组大鼠胰岛形态明显异常,局部iNOS相对浓度、AngⅡ、HomaIR增加,细胞内胰岛素相对浓度和FINS减少,差异有统计学意义（P＜0．01）;与D0组比较,D1组干预后大鼠胰岛形态改善,局部iNOS相对浓度、AngⅡ、HomaIR降低,细胞内胰岛素相对浓度和FINS增加,差异有统计学意义（P＜0．05）。结论Ang（1～7）可改善T2DM大鼠胰岛形态与功能。     

肾素—血管紧张素系统对大鼠心肌缺血和缺血再灌注后左心室功能的影响

目的　观察肾素 血管紧张素系统 (RAS)对大鼠心肌缺血和缺血再灌注后左心室功能的影响 ,以及给予氯沙坦和培哚普利干预的结果。方法　结扎大鼠左冠状动脉前降支造成心肌梗死 ,30min后松解结扎线再灌注心肌 6 0min ,假手术组只穿线不结扎 ,大鼠随机分为假手术组、生理盐水对照组、氯沙坦组、培哚普利组。监测大鼠心肌缺血 30min和缺血再灌注 6 0min时血流动力学和左心室功能、循环RAS组分、肌酸激酶 (CK)和去甲肾上腺素(NE)等指标。结果　①与假手术组比较 ,对照组的左室舒张末压在冠脉结扎和再灌注后均升高 ,而血压、左室收缩压和±dp/dt则显著降低 ;与对照组比较 ,两个用药组大鼠的心功能明显改善 ;②对照组血浆NE、CK水平明显高于假手术组和用药组 ;③对照组血浆各RAS组分水平比假手术组明显升高 ;用药组则明显抑制RAS活性。结论　①大鼠心肌缺血和再灌注后发生左心室功能障碍 ;②心肌缺血和缺血再灌注损伤后循环RAS被激活 ;③氯沙坦和培哚普利可以保护心肌细胞 ,改善左心室功能障碍     

培哚普利和缬沙坦对兔动脉粥样硬化脑组织核转录因子-κB,诱导型一氧化氮合酶表达的影响

目的建立兔高胆固醇-动脉粥样硬化模型,观察脑组织核转录因子κB(NF-κB)和诱导型一氧化氮合酶(iNOS)的阳性表达,探讨培哚普利、缬沙坦的干预效果及临床意义.方法30只雄性新西兰大白兔,随机分为4组:正常对照组(A组);高脂饮食组(B组);高脂饮食加培哚普利组(C组);高脂饮食加缬沙坦组(D组);喂饲8周后,取脑组织标本用免疫组化方法(SABC法)测定NF-κB的表达;分光光度法测定脑组织iNOS的活力.结果与对照组相比,高脂饮食组脑组织中NF-κB,iNOS水平明显升高(P<0.05);高脂饮食加培哚普利组及高脂饮食加缬沙坦组NF-κB,iNOS水平明显降低(P<0.05),但仍显著高于对照组(P<0.05).结论动脉粥样硬化致脑组织中NF-κB,iNOS表达发生的变化,与肾素-血管紧张素系统(RAS)的激活有关,培哚普利和缬沙坦从不同水平阻断RAS后,可减轻NF-κB,iNOS的表达,达到保护脑组织的作用.     

培哚普利对肾性高血压大鼠肾脏血管紧张素转换酶2的影响

目的采用两肾一夹(2K1C)高血压大鼠模型,了解培哚普利对高血压大鼠肾脏血管紧张素转换酶2(ACE2)表达的影响。方法40只雄性大鼠随机分为5组:正常对照组;2K1C高血压组;缬沙坦组;高剂量培哚普利组;低剂量培哚普利组。给药8周后,计算心重指数,放射免疫分析法测定血浆血管紧张素(Ang)Ⅱ水平,逆转录聚合酶链反应(RT-PCR)检测肾脏ACE2 mRNA表达,免疫组织化学法检测肾脏ACE2表达。结果培哚普利和缬沙坦治疗都明显降低高血压大鼠血压(P<0.01);RT-PCR和免疫组织化学染色结果显示2K1C高血压大鼠肾脏ACE2表达较正常大鼠降低(P<0.05);经培哚普利及缬沙坦治疗后大鼠ACE2表达明显高于2K1C高血压组(P<0.05)。高剂量培哚普利组血浆AngⅡ降低较缬沙坦组明显(P<0.01)。2K1C高血压大鼠心重指数明显高于各给药组(P<0.01)。结论2K1C高血压大鼠肾脏组织中ACE2表达降低,培哚普利及缬沙坦在降压的同时能增加肾脏组织ACE2的表达。     

大鼠胰岛与睾丸细胞共移植诱导同种胰岛移植免疫豁免

目的　探究大鼠胰岛与睾丸细胞共移植后睾丸细胞Fas配体表达能否对胰岛移植物提供免疫豁免作用。方法　将同种大鼠胰岛及睾丸细胞移植于糖尿病受体，观察移植物存活情况，并体外检测睾丸Sertoli细胞对活化淋巴细胞的抑制作用以及移植物内淋巴细胞凋亡情况。结果　单纯移植胰岛组移植胰岛平均存活期为(6±1)天。睾丸细胞和胰岛细胞共移植，当睾丸细胞数量为5×10     

The effects of culture-maintained pancreatic islets on metabolic parameters,renal function,and glomerular lesions in the diabetic rat

This study was undertaken for two purposes: to determine whether cultured islets of adult donor rats could be used successfully to reverse the metabolic abnormalities of diabetes of long-term duration and to determine the effect of islet transplantation on renal function and glomerular lesions in diabetic rats. Four groups of rats were studied: (1) five age-matched normal control rats, (2) seven rats with chronic streptozotocin-induced diabetes, (3) six chronically diabetic rats transplant-improved for 3 months, and (4) five acutely diabetic rats transplant-improved for 12 months. Transplanted rats received 1500 culture-maintained adult pancreatic islets injected into the portal vein. Following successful islet transplantation, the metabolic parameters of diabetes, including hyperglycemia, glycosuria, and polyuria, returned to normal. Evaluation of renal function revealed that clearances of isotopic inulin and ?-aminohippuric acid were not different among the groups. However, proteinuria was significantly greater in diabetic rats than ir both normal (p < 0.001) and transplant-improved rats (p < 0.01). There was striking glomerular immunofluorescence for IgG and C₃ in diabetic rats and none in the other groups. Quantitative morphometric electron microscopy revealed that the glomerular mesangium was significantly greater than normal in diabetic rats and decreased in the transplant-improved rats. The data indicate that culture-maintained islets from adult donors, as previously reported for diabetes of short-term duration, have the capacity to reverse the diabetic process in chronically diabetic rats; and that although rats with chronic diabetes do not exhibit an alteration of glomerular filtration rate, they do develop marked proteinuria, glomerular immunofluorescence, and mesangial thickening, all of which improve following successful islet transplantation.     

In vivo assessment of isolated pancreatic islet viability using the streptozotocin-induced diabetic nude rat

Summary In order to establish a model for the in vivo assessment of islet function we have used the Rowett nude rat with transplantation of allogeneic and xenogeneic (mouse) islets into the renal subcapsular space following a minimal period of diabetic induction. Thirty-one nude rats were given streptozotocin and 30 became diabetic with blood glucose levels of greater than 20 mmol/l at 48 h. Rat and mouse islets were prepared by intraductal collagenase and bovine serum albumin density gradient isolation. Eight rats received transplants of freshly prepared allogeneic islets and 8 rats received transplants of 48 h cultured allogeneic islets. Seven rats received transplants of 48 h cultured mouse islets. Diabetes was reversed in all animals and all remained normoglycaemic for 21 days. Graft removal by nephrectomy resulted in hyperglycaemia in 22 out of 23 animals. Histological examination of the grafts showed a band of endocrine tissue beneath the renal capsule which stained strongly positive for insulin and there was no evidence of lymphocytic infiltration/rejection. One rat remained normoglycaemic after graft removal, which may represent recovery of the animal's own islets from the streptozotocin-induced diabetes. Control rats remained diabetic until death. In conclusion, the athymic nude rat can be used for the assessment of allogeneic and xenogeneic islet function when a short (48 h) period of streptozotocin-induced diabetes is used. This model offers a potential method for assessing in vivo function of isolated human islets.     

The effect of hyperglycaemia on pancreatic islets transplanted into rats beneath the kidney capsule

Summary The effect of hyperglycaemia on islet transplantation in the rat has been examined in two ways, using syngeneic transplantation of 400 islets to the kidney capsule and subsequent measurement of kidney insulin content as a measurement of B-cell survival. Firstly, islets were transplanted into either diabetic or normal rats, then 6 months later the composite kidney/islet graft was transplanted into a normal rat. The insulin content was measured after a further 6 months and was found to be significantly reduced in islets exposed to hyperglycaemia in the primary recipient. These findings are interpreted as showing that long-term exposure of islets to hyperglycaemia results in B-cell loss. In the second experiment 400 islets were transplanted into either a long-term (6 months) diabetic or a normal rat. Two weeks later the composite kidney/islet graft was transplanted into a normal rat. The insulin content was measured after a further 6 months and no significant difference was found, whether the primary recipient was diabetic or not. These results are interpreted as showing that islet graft implantation is not impaired in long-term diabetic rats.     

脐带间充质干细胞联合移植对胰岛活性与功能的影响

目的:探讨脐带间充质干细胞(umbilical cord mesenchymal stem cells,UCMSCs)与胰岛细胞联合移植对胰岛活性与功能促进作用.方法:50只链脲佐菌素(streptozotocin,STZ)诱导的SD大鼠随机分为4组移植于肾包膜下,(1)500个胰岛移植组;(2)1×106个UCMSCs与500个胰岛细胞联合移植组;(3)1×106个UCMSCs组;(4)假手术(空白)对照组,仅于肾包膜下注入0.3mL生理盐水;术后测血糖水平、葡萄糖耐量试验(glucose tolerance test,GTT)、血清胰岛素水平以及达正常血糖水平率(以血糖浓度≤11.1mmol/L标准为正常)至28d.结果:联合移植组术后血糖水平最低,血清胰岛素水平更高,达正常血糖浓度率优于其他3组,在术后14d GTT较其他3组好,血清胰岛素水平较其他3组好,血糖水平、血清胰岛素水平、GTT水平UCMSCs组与对照组间均无统计学差异,单纯UCMSCs组无1例动物血糖水平达正常.结论:间充质干细胞与胰岛联合移植能有效提高胰岛细胞活性与功能.     

Prevention of hyperglycemia improves the long-term result of islet transplantation in streptozotocin-diabetic rats.

We examined the hypothesis that prevention of hyperglycemia during the critical period immediately following islet transplantation will improve the outcome of the transplantation in streptozotocin-diabetic rats. Two days after intravenous injection of streptozotocin (70 mg/kg), 400 or 1,000 islets were transplanted into the left kidney subcapsular space. A group of rats transplanted with 400 islets was treated with insulin from 1 day before transplantation and for 7 days. Intravenous glucose infusion was performed at 10 days and 3 months after transplantation. In addition, at 3 months, the grafts were examined by light and electron microscopy. We found that rats transplanted with 400 islets without any concomitant insulin administration remained diabetic throughout the 3-month period and no plasma insulin response was induced by glucose infusion in these rats. In contrast, diabetic rats transplanted with 400 islets and treated with insulin for 7 days remained normoglycemic throughout the 3-month period, as did rats transplanted with 1,000 islets. Furthermore, these rats had normal glucose-stimulated insulin secretion both at 10 days and at 3 months after transplantation. Moreover, islet grafts from rats transplanted with 400 islets and administered insulin as well as from rats transplanted with 1,000 islets were morphologically normal, and following removal of the graft, hyperglycemia developed rapidly. In contrast, the islet grafts from rats transplanted with 400 islets without concomitant insulin administration had only few insulin cells. Thus, by preventing hyperglycemia at the time of islet transplantation, the long-term result of islet transplantation was improved. Therefore, the ambient glucose level initially following islet transplantation is critical for the long-term result.     

Soybean oil treatment impairs glucose-stimulated insulin secretion and changes fatty acid composition of normal and diabetic islets

We investigated the effect of sub-chronic soybean oil (SO) treatment on the insulin secretion and fatty acid composition of islets of Langerhans obtained from Goto-Kakizaki (GK), a model of type 2 diabetes, and normal Wistar rats. We observed that soybean-treated Wistar rats present insulin resistance and defective islet insulin secretion when compared with untreated Wistar rats. The decrease in insulin secretion occurred at all concentrations of glucose and arginine tested. Furthermore we observed that soybean-treated normal islets present a significant decrease in two saturated fatty acids, myristic and heneicosanoic acids, and one monounsaturated eicosenoic acid, and the appearance of the monounsaturated erucic acid. Concerning diabetic animals, we observed that soybean-treated diabetic rats, when compared with untreated GK rats, present an increase in plasma non-fasting free fatty acids, an exacerbation of islet insulin secretion impairment in all conditions tested and a significant decrease in the monounsaturated palmitoleic acid. Altogether our results show that SO treatment results in a decrease of insulin secretion and alterations on fatty acid composition in normal and diabetic islets. Furthermore, the impairment of insulin secretion, islet erucic acid and fasting plasma insulin levels are similar in treated normal and untreated diabetic rats, suggesting that SO could have a deleterious effect on β-cell function and insulin sensitivity.     

In vitro culture--a method of pancreatic islet preservation for transplantation

Pancreatic islets from adult rats, accumulated daily for a period of 2 wk, were cultured in artificial capillary culture units that were perfused with nutrient medium. Viability and functional capacity of these islets in this in vitro culture system has been shown to be maintained. The therapeutic efficiency of cultured islets was comparable to freshly isolated islets when assessed by transplantation into streptozotocin-induced diabetic rats. Intraportal implantation of either freshly isolated or cultured islets into isogeneic diabetic rats resulted in normal weight gain as well as complete reversal of hyperglycemia, glycosuria, and polyuria in the diabetic rat recipient. The normoglycemic state was sustained for more than 12 mo. Plasma glucose clearance rate (KG) were significantly lower in both the transplanted fresh or cultured islet groups than in the normal controls; however, the cultured islets were not less effective than the fresh islets. The results of the present study indicate the feasibility of accumulation of large numbers of islets in the in vitro culture system without any loss of therapeutic efficiency when implanted in vivo. Further improvement of this in vitro culture system can thus be applied in islet preservation for islet transplantation.