CE抑制剂对糖尿病大鼠早期肾脏肥大的抑制作用及机制

目的　研究ACE抑制剂对糖尿病大鼠早期肾脏肥大的抑制作用及机制。方法　大鼠随机分单侧肾切除对照组、糖尿病组及糖尿病苯那普利治疗组。应用Northern杂交检测各组肾皮质TGFβ1mRNA表达 ,Western杂交检测各组肾皮质TGFβ1和 p2 1CIP1蛋白表达 ,荧光分光光度法测定血浆、肾皮髓质ACE活性。结果　糖尿病大鼠 1wk后体重下降(P <0 0 5 )伴肾重 /体重增加 (P <0 0 5 ) ,血浆ACE活性有所下降而肾皮质ACE活性却有所上升。Northern杂交表明糖尿病组肾皮质TGFβ1mRNA表达比对照组增加 1 3倍 ,Western杂交表明糖尿病组肾皮质TGFβ1和p2 1CIP1蛋白表达增加 ;苯那普利治疗 1wk对糖尿病肾脏肥大有抑制作用 ,对血浆、肾皮髓质ACE活性抑制分别达 89 0 %、70 0 %与70 5 % ,对肾皮质TGFβ1mRNA及TGFβ1和p2 1CIP1蛋白表达抑制分别达 4 7 7%、4 9 5 %与 6 0 0 %。结论　ACE抑制剂对糖尿病肾脏肥大的抑制作用机制可能部分与抑制肾组织TGFβ1和p2 1CIP1蛋白表达有关     

血小板衍化生长因子及其受体在糖尿病大鼠肾皮质中的表达及苯那普利的调节作用

目的 探讨PDGF-B及其β受体在糖尿病大鼠肾皮质中的表达及苯那普利对它的调节作用。方法 Wistar大鼠随机分为3组:单侧肾切除组、糖尿病组和糖尿病苯那普利治疗组,观察4周后血糖、血清胰岛素、肌酐水平和体重、肾重变化,并测定了血浆和肾皮、髓质ACE活性,应用Northern杂交检测肾皮质PDGF-BmRNA水平,Western杂交检测肾皮质 PDGF-β受体蛋白的表达。结果 苯那普利能明显改善糖尿病大鼠的异常糖代谢并降低血肌酐水平,延缓体重下降,抑制肾重的增加,抑制肾皮质ACE活性达88.8％;Northern杂交表明糖尿病大鼠肾皮质PDGF-BmRNA表达上调达对照组4倍,苯那普利对其不产生明显影响,Western杂交表明糖尿病大鼠的肾皮质PDGF-β受体蛋白明显增高为对照组2.5倍,苯那普利可下调其表达。结论 苯那普利虽对糖尿病大鼠肾皮质PDGF-BmRNA不产生明显影响,但可显著下调其β受体蛋白的表达。     

苯那普利与厄贝沙坦对心衰大鼠心室重构过程中AngⅡ受体及ACE2的影响

目的探讨苯那普利、厄贝沙坦及两者联合用药对心衰大鼠心室重构过程中心肌血管紧张素Ⅱ1型受体(AT1R)、2型受体(AT2R)及ACE2蛋白表达的影响。方法采用大鼠腹主动脉缩窄法造成压力负荷性心肌肥厚致心力衰竭模型。苯那普利或(和)厄贝沙坦连续给药8wk,检测血流动力学参数、心脏指数、心肌和血浆AngⅡ含量、心肌中AT1R、AT2R和ACE2蛋白的表达情况。结果模型组心脏指数、LVEDP、血浆和心肌AngⅡ的含量及心肌AT1R、AT2R和ACE2蛋白的表达明显升高;各治疗组心脏指数、LVEDP明显下降;苯那普利组血浆和心肌AngⅡ的含量降低,厄贝沙坦组心肌AT1R蛋白的表达明显下降而AT2R和ACE2蛋白的表达明显升高,联合应用具有协同作用。结论联合应用苯那普利和厄贝沙坦对改善心衰大鼠心室重构具有协同作用,可能与AngⅡ和AT1R的下调而AT2R和ACE2的上调有关。     

苯那普利对糖尿病大鼠肾皮质TGFβ_1及其受体表达的影响

目的探讨苯那普利对糖尿病大鼠肾皮质ＴＧＦβ１及其受体表达的影响。方法大鼠随机分单侧肾切除组（Ｃ组）;糖尿病组（Ｄ组）及糖尿病苯那普利治疗组（１０ｍｇ·ｋｇ－１·ｄ－１,灌胃,ＤＢ组）,观察４ｗｋ后各组血糖、血胰岛素、血肌酐水平及体重、肾重和肾组织蛋白含量的变化,采用荧光分光光度法测定血浆及肾皮质、髓质ＡＣＥ活性。应用Ｎｏｒｔｈｅｒｎ杂交检测各组肾皮质ＴＧＦβ１,１α（ＩＶ）前胶原及ＦＮｍＲＮＡ表达;Ｗｅｓｔｅｒｎ杂交检测各组肾皮质ＴＧＦβ１及细胞膜ＴβＲⅠ蛋白表达。结果苯那普利治疗４ｗｋ后能够明显缓解糖尿病大鼠高血糖、低胰岛素血症、血肌酐水平上升及体重下降、肾脏肥大。Ｎｏｒｔｈｅｒｎ杂交表明糖尿病大鼠肾皮质ＴＧＦβ１、１α（ＩＶ）前胶原及ＦＮｍＲＮＡ表达分别３．９４、４．２５及１．５０倍,Ｗｅｓｔｅｒｎ杂交表明肾皮质ＴＧＦβ１及细胞膜ＴβＲⅠ蛋白表达分别上调３．１０、１．００倍,苯那普利治疗４ｗｋ后对它们均有明显抑制作用。另外,尽管糖尿病大鼠血浆ＡＣＥ活性明显下降,肾皮质ＡＣＥ活性却明显增加,苯那普利治疗后对血浆及肾皮质ＡＣＥ活性抑制分别达９２．００％和８８．７０％。结论苯那普利可抑制高血糖状态下肾皮质ＴＧ?     

替米沙坦对2型糖尿病大鼠心肌脂联素受体2葡萄糖转运蛋白4表达的影响

目的探讨替米沙坦对2型糖尿病大鼠心肌组织脂联素受体2(AdipoR2)及葡萄糖转运蛋白4(GluT4)表达的影响。方法30只雄性Wistar大鼠,随机分为3组:健康对照组(A组),糖尿病组(B组)和糖尿病替米沙坦治疗组(C组),每组各10只。采用高糖高脂饮食加小剂量链脲佐菌素(STZ)的方法诱导糖尿病模型。用逆转录-聚合酶链反应(RT—PCR)的方法测定大鼠心肌AdipoR2mRNA、GluT4mRNA的表达,用免疫组织化学法检测AdipoR2蛋白在心肌组织中的表达,用放射免疫法检测血浆脂联素水平。结果与A组比较,B组糖尿病大鼠心质量/体质量增加,血浆脂联素水平、心肌AdipoR2mRNA和蛋白表达以及GluT4mRNA表达均显著降低。替米沙坦治疗后,C组糖尿病大鼠心质量/体质量降低,血浆脂联素水平、心肌AdipoR2mRNA和蛋白表达以及GluT4mRNA表达均显著升高。结论2型糖尿病大鼠心肌AdipoR2及GluT4表达水平降低。替米沙坦上调2型糖尿病大鼠心肌AdipoR2及GluT4表达,促进心肌葡萄糖氧化,减轻心脏肥大,产生心脏保护作用。     

苯那普利及坎地沙坦对自发性高血压大鼠心肌肥厚过程中SMAD蛋白的影响

目的观察自发性高血压大鼠(SHR)心肌肥厚程度与转化生长因子β1(TGF-β1)、Smad3和Smad7蛋白的表达及苯那普利、坎地沙坦的治疗作用。方法12wk龄SHR连续灌胃给予苯那普利或(和)坎地沙坦,每2wk测定尾动脉压,12wk后检测心脏构型、心脏指数、心肌细胞大小、心肌和血浆AngⅡ含量、心肌中TGF-β1、Smad3和Smad7蛋白的表达。结果SHR血压、心脏指数、心肌细胞大小及心肌组织中TGF-β1、Smad3蛋白明显增加,苯那普利或坎地沙坦治疗均能使上述指标减轻,联合应用具有协同作用,且能降低心肌和血浆AngⅡ含量;苯那普利或坎地沙坦治疗能增加在SHR中表达下降的Smad7蛋白,但两者合用对Smad7表达改善不明显。结论苯那普利和坎地沙坦联合应用对改善自发性高血压大鼠心肌肥厚具有协同作用,可能与调节AngⅡ水平、减少高血压心肌肥厚过程中TGF-β1和Smad3表达有关。     

苯那普利与厄贝沙坦对心衰大鼠心肌胶原的影响及机制探讨

目的观察苯那普利、厄贝沙坦单用及联合应用对慢性心力衰竭(chronic heart failure,CHF)大鼠心肌胶原的影响,并深入探讨其作用机制。方法采用腹主动脉缩窄法,造成压力负荷性心肌肥厚致心力衰竭大鼠模型。苯那普利或(和)厄贝沙坦连续给药8周,监测大鼠尾动脉收缩压,透射电镜检测心肌细胞超微结构,碱水解法检测心肌组织羟脯氨酸含量,并评估心肌胶原交联程度,免疫组化测定心肌Ⅰ型、Ⅲ型胶原蛋白水平,Western blot检测心肌p-38MAPK和p-p38MAPK的蛋白表达。结果与心衰模型组相比,各治疗组血压无明显变化,但心肌羟脯氨酸含量、胶原交联程度、Ⅰ型胶原、Ⅲ型胶原、p-p38MAPK蛋白表达明显降低(P<0.05),其中联合应用疗效最好。结论苯那普利与厄贝沙坦联用对改善心衰大鼠心肌胶原纤维的总量与性质具有协同作用,可能与下调p-p38MAPK蛋白表达有关。     

缬沙坦及苯那普利对慢性肾衰竭大鼠心肌病变的治疗作用

目的观察缬沙坦、苯那普利及缬沙坦和苯那普利联用对慢性肾衰竭大鼠心肌病变的改善作用,探讨其作用机制。方法SD♂大鼠40只,通过5/6肾切除法制备慢性肾衰竭模型,术后2wk随机分为模型组、缬沙坦组、苯那普利组及缬沙坦与苯那普利联合治疗组,并设假手术组作为对照。术后第10周末测定各组大鼠血压及肾功能(Scr、BUN)后处死大鼠,取出心脏进行病理组织学观察;并采用原位杂交方法检测心肌内皮素-1(ET-1)mRNA及一氧化氮合酶3(eNOS-3)mRNA的转录水平。结果模型组术后第10周收缩压、心脏重量、心脏重量指数、左室重量及左室重量指数均明显增加,缬沙坦、苯那普利及联合治疗组能明显降低5/6肾切除大鼠收缩压、心脏重量、心脏重量指数、左室重量及左室重量指数(P<0.01);缬沙坦组、苯那普利组及联合治疗组心肌ET-1mRNA、eNOS-3 mRNA转录水平均较模型组减弱。结论缬沙坦、苯那普利及缬沙坦与苯那普利联合治疗能防治慢性肾衰竭大鼠的左室肥厚,其机制可能是通过下调心肌ET-1 mRNA、eNOS-3 mRNA转录来实现的。     

仙人掌果多糖降血糖作用及其机制

目的：研究仙人掌果多糖提取物（CFPE）的降血糖作用及其相关分子机制。方法：采用链脲佐菌素（STZ）复制糖尿病大鼠模型。连续给药8周,观察各组大鼠体重和糖化血红蛋白（GHb）的变化。运用RT-PCR技术,检测糖尿病大鼠肝组织和骨骼肌的胰岛素受体（IR）及骨骼肌葡萄糖转运蛋白4（GluT4）mRNA的表达。结果：与模型组比较,CFPE可明显降低糖尿病大鼠GHb含量,可使糖尿病大鼠体重明显回升;增加肝脏和骨骼肌IR及骨骼肌GluT4 mRNA的表达。结论：CFPE对糖尿病大鼠有明显的降血糖作用,其机制可能与其增加肝脏和骨骼肌IR以及骨骼肌GluT4 mRNA的表达有关。     

自发性高血压大鼠(SHR)心肌纤维化和巨噬细胞关系的研究——苯那普利干预试验

目的探讨巨噬细胞在自发性高血压大鼠(SHR)心肌纤维化中的作用以及苯那普利对其影响及其机制。方法12wk♂SHR分为高血压组(SHR,n=10)、苯那普利治疗组(BenL、BenH亚组,分别予苯那普利1.7、17mg.kg-1.d-1灌胃;n=10),另设年龄、性别配对的WKY大鼠为对照(WKY,n=10)。干预18wk后,测量和计算各组大鼠收缩压(SBP)、左室重量(LVM)、左室重量指数(LVMI)、左室心肌胶原含量和巨噬细胞数目;逆转录-聚合酶链反应(RT-PCR)测定各组大鼠心肌转化生长因子-β1(1(TGF-β1)和白介素-6(IL-6)的转录水平。结果SHR组SBP较WKY大鼠升高(P<0.01),BenH组的SBP明显低于SHR组(P<0.01),BenL组SBP无明显变化;SHR组较WKY心肌中巨噬细胞数目明显增多,TGF-β1和IL-6的信使核糖核酸(mR-NA)水平也明显升高(P<0.01);而BenL和BenH组SHR心肌中巨噬细胞数目和TGF-β1及IL-6的mRNA水平均较SHR组降低(P<0.05);大鼠心肌中巨噬细胞数目分别与心肌胶原容积分数(CVF)、心肌内血管周围胶原面积(PVCA)含量呈正相关(P<0.01)。结论巨噬细胞在SHR大鼠心肌纤维化中具有重要作用,苯那普利可减轻SHR心肌纤维化和巨噬细胞浸润,且可下调TGF-β1和IL-6的mRNA表达。     

Prevention of incipient diabetic cardiomyopathy by high-dose thiamine

Diabetic cardiomyopathy can progress toward overt heart failure with increased mortality. The hexosamine biosynthesis pathway has been implicated in signaling for fibrosis by the kidney. Thiamine (vitamin B(1)) is an indispensable coenzyme and required at intracellular glucose metabolism. In this study, we assessed if decrease of flux through the hexosamine biosynthesis pathway induced by high-dose thiamine therapy counteracts diabetes-induced cardiac fibrosis. The diabetes model used was the streptozotocin-induced diabetic rat. Normal control and diabetic rats were studied for 2 weeks with and without thiamine, and followings were analyzed; plasma biochemicals (total cholesterol and triglycerides), morphological changes, mRNA abundance relevant to cardiac failure (brain natriuretic peptide) and fibrosis (transforming growth factor-beta1, thrombospondine, fibronectin, plasminogen activator-I and connective tissue growth factor) as well as and matrix metalloproteinase activity were investigated. Thiamine repletion prevented diabetes-induced cardiac fibrosis without changes in plasma glucose concentration. This was achieved by prevention of thiamine depletion, increased pro-fibrotic mRNA abundance and decreased metalloproteinase activity in the heart of diabetic rats. O-glycosylated protein was significantly higher in the left ventricular of diabetic rats compared to control rats, which was decreased by thiamine administration. Thiamine repletion prevented diabetes-induced cardiac fibrosis in experimental diabetes, probably by suppression of hexosamine biosynthesis pathway.     

贝那普利对阿霉素肾病大鼠肾脏保护作用的研究

目的：观察贝那普利对阿霉素肾病大鼠形态学和肾皮质结蛋白表达改变的影响,探讨其对足细胞损伤的保护作用。方法：SD大鼠随机分为正常对照组、阿霉素肾病组和贝那普利治疗组。分别于给药4、7周后留取标本,检测24h蛋白尿、血肌酐,肾组织行形态学检查,应用免疫组化法检测肾皮质中结蛋白表达。结果：肾病组大鼠尿蛋白排泄明显高于对照组（P〈0．05）,且有明显的肾小球足细胞损伤的病理学改变。肾皮质结蛋白表达增加（P〈0．05）。贝那普利治疗后肾脏病理明显减轻,结蛋白表达降低（P〈0．05）。结论：在阿霉素肾病中,贝那普利可改善肾小球足细胞的损伤程度,降低结蛋白表达,对肾小球起保护作用。     

Celecoxib,a selective cyclooxygenase-2 inhibitor,inhibits retinal vascular endothelial growth factor expression and vascular leakage in a streptozotocin-induced diabetic rat model

Overexpression of vascular endothelial growth factor (VEGF) is implicated in the development of vascular leakage and retinal neovascularization in diabetic subjects. The objective of this study was to determine whether celecoxib, a selective cyclooxygenase-2 enzyme inhibitor, reaches ocular tissues following oral administration and inhibits the retinal VEGF expression and vascular leakage in a streptozotocin-induced diabetic rat model. After administering a single intraperitoneal injection of streptozotocin (60 mg/kg) to Sprague-Dawley rats and ensuring the induction of diabetes at the end of 24 h, celecoxib was administered b.i.d. by oral gavage (50 mg/kg). On day 8, the animals were sacrificed and the retinal VEGF and cyclooxygenase-2 mRNA levels, ocular tissue celecoxib concentrations, and the vitreous/plasma protein ratio were determined. In diabetic rats, the retinal VEGF mRNA expression was 2.3-fold compared to controls, with a corresponding increase in cyclooxygenase-2 mRNA expression. Celecoxib treatment inhibited VEGF mRNA expression without any significant reduction in cyclooxygenase-2 mRNA. Furthermore, the retinal vascular leakage estimated as vitreous to plasma protein ratio increased in diabetic animals from 0.35+/-0.1 to 1.1+/-0.1 and celecoxib treatment significantly decreased this ratio to 0.4+/-0.1. Celecoxib levels were 24.8+/-6.6, 1.9+/-1, 1.7+/-0.8, and 6.9+/-0.9 ng/mg in the retina, vitreous, lens, and cornea, respectively. The plasma celecoxib levels were 85+/-24 ng/ml. Thus, celecoxib reaches the retina after oral administration and reduces diabetes-induced retinal VEGF mRNA expression and vascular leakage by inhibiting the activity of cyclooxygenase-2 enzyme.     

Effect of taurine supplementation on cytochrome P450 2E1 and oxidative stress in the liver and kidneys of rats with streptozotocin-induced diabetes

To investigate whether diabetes-induced alterations of CYP2E1 and oxidative stress can be modulated by dietary taurine supplementation, male Wistar rats were divided into non-diabetic, diabetic, and diabetic taurine-supplemented groups (administered at 2% in the drinking water). Increased levels of CYP2E1-catalyzed p-nitrophenol hydroxylation were found in liver and kidney microsomes of rats with STZ-induced diabetes compared to those of non-diabetic control rats. Immunoblot and RT-PCR analyses of CYP2E1 protein and mRNA levels in the liver and kidneys showed the same trend as with enzyme activities. Taurine supplementation significantly decreased the enzyme activity and expression (protein and mRNA) of CYP2E1 in diabetic rat kidneys. Plasma β-hydroxybutyrate concentration was significantly reduced in taurine-treated diabetic rats. The induction of heme oxygenase-1 mRNA was suppressed by taurine treatment in diabetic rat kidneys. An increase in reduced glutathione (GSH) and a higher ratio of reduced to oxidized glutathione (GSH/GSSG) together with lower values of thiobarbituric acid-reactive substances (TBARS) were observed in the kidneys of taurine-treated diabetic rats. However, taurine supplementation caused only a slight or insignificant effect on these alternations in the liver of diabetic rats. Our results show dietary taurine may reduce CYP2E1 expression and activity, and oxidative stress in kidneys of diabetic rats.