实验性糖尿病大鼠认知功能障碍与额叶皮质、海马细胞凋亡关系的研究

目的 探讨糖尿病(DM)大鼠认知功能与额叶皮质和海马神经元凋亡的关系.方法 电迷宫法测试28只DM大鼠(DM组)和30只正常大鼠(NC组)学习能力,并检测额叶皮质和海马发生凋亡的神经元数目和bcl-2、Bax基因表达.结果 DM组大鼠学习能力明显下降,额叶皮质和海马细胞凋亡数高于NC组,bcl-2表达减少,而Bax表达增加.DM组大鼠达到学会标准所需训练次数与额叶皮质和海马细胞凋亡数呈正相关,而NC组大鼠两者无相关性.结论 高血糖状态下额叶皮质与海马凋亡调节基因表达改变引起的细胞凋亡增加可能与糖尿病认知功能障碍有关.     

泛素和凋亡相关因子在糖尿病大鼠脑内的表达

目的 探讨持续高血糖状态对大鼠学习记忆能力的影响以及泛素和凋亡相关因子表达的变化,为糖尿病脑病的发病机制提供相关依据.方法 雄性SD大鼠,随机分为正常对照组和糖尿病模型组,腹腔注射链脲佐菌素(streptozotoein,STZ)建立糖尿病大鼠模型.电迷宫法测试各组大鼠的学习记忆能力;尼氏染色和免疫组织化学法观察大鼠额叶皮质和海马区的组织学变化.原位末端标记法(TUNEL)检测大鼠额叶皮质和海马区凋亡细胞数;免疫印迹法(Western-blot)检测大鼠额叶皮质和海马区Bcl-2、P53蛋白的表达;反转录聚合酶链反应法(RT-PCR)检测大鼠额叶皮质和海马区泛素基因的表达.结果 糖尿病组大鼠学习记忆能力明显下降,额叶皮质和海马区神经细胞凋亡数高于对照组,泛素、P53表达水平明显高于对照组,而Bcl-2表达显著减少(P＜0.05).结论 高血糖状态下大鼠额叶皮质与海马区的泛素、P53表达增加,Bcl-2表达降低,大鼠额叶皮质和海马区凋亡细胞数明显增多,从而引起大鼠学习记忆能力下降.     

波动性高糖诱导大鼠胰岛β细胞凋亡的研究

近年来,胰岛细胞凋亡成为糖尿病研究的一大热点.葡萄糖毒性在糖尿病慢性高血糖状态下可诱导胰岛β细胞凋亡,但以往的研究多集中于慢性持续性高糖的作用,而对于更符合糖尿病患者实际情况波动性高糖的作用报道较少,且具体作用机制不清.因此,我们于2009年7月至2010年4月通过观测大鼠胰岛细胞株(Ins-1)细胞凋亡情况及检测氧化应激相关因子,探讨波动性高糖对胰岛β细胞凋亡的影响及可能机制.     

波动性高糖诱导大鼠胰岛β细胞凋亡的研究

近年来,胰岛细胞凋亡成为糖尿病研究的一大热点.葡萄糖毒性在糖尿病慢性高血糖状态下可诱导胰岛β细胞凋亡,但以往的研究多集中于慢性持续性高糖的作用,而对于更符合糖尿病患者实际情况波动性高糖的作用报道较少,且具体作用机制不清.因此,我们于2009年7月至2010年4月通过观测大鼠胰岛细胞株(Ins-1)细胞凋亡情况及检测氧化应激相关因子,探讨波动性高糖对胰岛β细胞凋亡的影响及可能机制.     

波动性高糖诱导大鼠胰岛β细胞凋亡的研究

近年来,胰岛细胞凋亡成为糖尿病研究的一大热点.葡萄糖毒性在糖尿病慢性高血糖状态下可诱导胰岛β细胞凋亡,但以往的研究多集中于慢性持续性高糖的作用,而对于更符合糖尿病患者实际情况波动性高糖的作用报道较少,且具体作用机制不清.因此,我们于2009年7月至2010年4月通过观测大鼠胰岛细胞株(Ins-1)细胞凋亡情况及检测氧化应激相关因子,探讨波动性高糖对胰岛β细胞凋亡的影响及可能机制.     

波动性高糖诱导大鼠胰岛β细胞凋亡的研究

近年来,胰岛细胞凋亡成为糖尿病研究的一大热点.葡萄糖毒性在糖尿病慢性高血糖状态下可诱导胰岛β细胞凋亡,但以往的研究多集中于慢性持续性高糖的作用,而对于更符合糖尿病患者实际情况波动性高糖的作用报道较少,且具体作用机制不清.因此,我们于2009年7月至2010年4月通过观测大鼠胰岛细胞株(Ins-1)细胞凋亡情况及检测氧化应激相关因子,探讨波动性高糖对胰岛β细胞凋亡的影响及可能机制.     

非糖尿病大鼠急性心肌梗死后急性高血糖对心肌细胞线粒体膜电位和细胞色素C的影响

目的 研究急性心肌梗死后急性高血糖对大鼠心肌细胞线粒体膜电位和细胞色素C的影响.方法 结扎40只雄性SD大鼠左冠状动脉前降支建立急性心肌梗死模型后随机分为4组:生理盐水组、高糖1组、高糖2组和胰岛素组,另取10只SD大鼠为假手术组,术中监测血糖水平,实验终点观察各组大鼠细胞凋亡指数、线粒体和胞浆内细胞色素C表达以及线粒体膜电位变化.结果 与假手术组比较,余各组细胞凋亡指数表达均增高,线粒体膜电位均降低;胞浆细胞色素C表达增加而线粒体内细胞色素C表达减少(P<0.05).与高糖2组比较, 其余各组细胞凋亡指数显著减低,线粒体膜电位显著增高,细胞色素C胞浆表达显著减少而线粒体表达显著增加(P<0.05).生理盐水组组、胰岛素组、高糖1组细胞凋亡指数、线粒体膜电位、胞质和线粒体中细胞色素C表达量差异无显著性(P>0.05).结论 急性心肌梗死后急性高血糖可能通过线粒体途径显著促进细胞凋亡,注射胰岛素降低血糖能有效地减少细胞凋亡.     

缺血期急性高血糖加重大鼠心肌缺血/再灌注损伤

目的探讨急性高血糖对大鼠心肌缺血/再灌注损伤（RMMI）缺血期和再灌注期的影响,并分析不同时期的高血糖与心肌损伤之间的关系。方法制备急性大鼠RMMI模型（缺血30 min,再灌注6 h）,静脉输注高浓度的葡萄糖液,造成急性高血糖动物模型。将SD大鼠随机分为4组:假手术组（SHAM）,生理盐水对照组（CON）,缺血期高糖组（HGI）和再灌注期高糖组（HGR）。术中监测血糖水平,再灌注结束后检测心肌酶谱（CK,LDH）水平和心肌梗死（MI）面积。结果静脉输注高糖后大鼠血糖水平迅速而显著升高,造成缺血期和再灌注期急性高血糖。与CON组相比较,HGI组心肌酶谱水平显著升高,MI面积显著扩大[（46±9）%vs（38±6）%,P<0.05];而HGR组的心肌酶谱水平和MI面积与CON组相比无显著差异[（39±6）%vs（38±6）%]。结论缺血期急性高血糖可加重大鼠RMMI。     

应激性高血糖对大鼠心肌缺血再灌注损伤的观察

目的观察应激性高血糖（SHG）对大鼠心肌缺血/再灌注损伤（MIRI）时缺血期和再灌注期的不同影响,分析不同时期的SHG与心肌损伤之间的关系。方法成年SD大鼠50只随机分为5组：假手术组（SHAM）、高糖组（HG）、生理盐水对照组（CON）、缺血期高糖组（HGI）和再灌注期高糖组（HGR）,每组各10只;制备大鼠MIRI模型（缺血30min,再灌注3h）,静脉输注高浓度的葡萄糖液,造成应激性高血糖动物模型;术中监测血糖水平,再灌注结束后检测血清乳酸脱氢酶（LDH）水平,伊文斯兰染色测心肌梗死面积（Infarct size,IS）,分析不同时期高血糖对心肌损伤的影响。结果与SHAM组相比,静脉输注高糖LDH表达并未明显改变;与CON组相比,机体发生MIMI时,LDH水平升高,HGI组LDH水平明显升高,IS显著扩大,差异有统计学意义（P〈0.01）;而HGR组心肌酶谱水平和IS与CON组比较差异无统计学意义。结论缺血期应激性高血糖加重大鼠心肌缺血/再灌注损伤。     

脂联素抑制高浓度葡萄糖诱导的SD大鼠原代胰岛β细胞凋亡的研究

目的探讨脂联素对高浓度葡萄糖诱导的原代大鼠胰岛β细胞凋亡的影响及其可能机制。方法分离和培养原代胰岛细胞,分组干预并检测胰岛细胞凋亡率及相关基因表达水平。结果高糖组胰岛β细胞凋亡率、Caspase-3和BaxmRNA表达量显著高于正常葡萄糖和高糖联合脂联素组（P〈0．01）。结论脂联素可以抑制高糖诱导的大鼠胰岛β细胞凋亡,其作用机制可能与凋亡相关基因Caspase-3与Bax基因表达下调有关。     

转化生长因子βI型受体在糖尿病大鼠肾皮质中的表达及苯那普利对其 …

目的 研究转化生长因子βⅠ型受体（ＴＧＦβＲⅠ）在糖尿病大鼠肾皮质中的表达及血管紧张素转换酶抑制剂苯那利普利对其调节作用。方法 纯种雄性成年Ｗｉｓｔａｒ大鼠随机分单侧肾切除组（Ｃ组）,糖尿病组（Ｄ组）和糖尿病苯那普利治疗组（ＤＢ组）,给药４周末观察各组血清、血肌酐水平、体重、肾重和肾组织蛋白含量及血浆、肾皮质、髓质血管紧张素转换酶（ＡＣＥ）活性的变化;分别采用逆转录聚合酶链反应（ＲＴ－ＰＣＲ）、Ｎ     

Pathogenesis of diabetic nephropathy: the role of oxidative stress and protein kinase C

Hyperglycemia, a well recognized pathogenetic factor of long-term complications in diabetes mellitus, not only generates more reactive oxygen species but also attenuates antioxidative mechanisms through glycation of the scavenging enzymes. Therefore, oxidative stress has been considered to be a common pathogenetic factor of the diabetic complications including nephropathy. A causal relationship between oxidative stress and diabetic nephropathy has been established by observations that (1) lipid peroxides and 8-hydroxydeoxyguanosine, indices of oxidative tissue injury, were increased in the kidneys of diabetic rats with albuminuria; (2) high glucose directly increases oxidative stress in glomerular mesangial cells, a target cell of diabetic nephropathy; (3) oxidative stress induces mRNA expression of TGF-beta1 and fibronectin which are the genes implicated in diabetic glomerular injury, and (4) inhibition of oxidative stress ameliorates all the manifestations associated with diabetic nephropathy. Proposed mechanisms involved in oxidative stress associated with hyperglycemia are glucose autooxidation, the formation of advanced glycosylation end products, and metabolic stress resulting from hyperglycemia. Since the inhibition of protein kinase C (PKC) effectively blocks not only phorbol ester-induced but also high glucose- and H2O2-induced fibronectin production, the activation of PKC under diabetic conditions may also have a modulatory role in oxidative stress-induced renal injury in diabetes mellitus.     

血管紧张素转换酶抑制剂对糖尿病大鼠肾皮质细胞膜胰岛素受体的调节

目的研究血管紧张素转换酶抑制剂（ＡＣＥＩ）对糖尿病大鼠肾皮质细胞膜胰岛素受体表达的调节。方法实验大鼠随机分三组：单侧肾切除组（Ｃ组,６例）;糖尿病组（Ｄ组,７例）及糖尿病苯那普利治疗组（ＤＢ组,７例）。观察四周后各组血糖、血胰岛素及血肌酐水平和体重、肾重及肾重／体重之比的变化,测定血浆、肾皮质及髓质血管紧张素转换酶（ＡＣＥ）活性,采用Ｗｅｓｔｅｒｎ杂交分析肾皮质细胞膜胰岛素受体蛋白表达。结果苯那普利治疗四周后能够改善糖尿病大鼠血糖、血胰岛素及血肌酐水平的异常,对糖尿病肾脏肥大有显著抑制作用,对血浆、肾皮质及髓质ＡＣＥ活性抑制分别达９２．００％,８８．７７％与７３．４０％。肾皮质细胞膜胰岛素受体蛋白表达比对照组增加约２．１０倍,苯那普利治疗四周后对此有明显的下调作用。结论苯那普利可下调糖尿病状态下肾皮质细胞膜胰岛素受体蛋白高表达,这可能是其对糖尿病肾脏保护作用的重要机制之一。     

糖尿病肾病的表观遗传学机制

表观遗传学是指DNA序列不发生变化的情况下基因表达发生的可遗传的改变.大量的研究发现,表观遗传机制参与调控糖尿病肾病的肾脏纤维化、足细胞凋亡、慢性炎性反应、氧化应激等各个病理生理过程.     

Proinsulin C-peptide abrogates type-1 diabetes-induced increase of renal endothelial nitric oxide synthase in rats

BACKGROUND: Proinsulin C-peptide shows ameliorative effects on diabetic complications, possibly through the production of nitric oxide (NO). On the contrary, increased local availability of NO and expression of endothelial NO synthase (eNOS) in the renal endothelium are shown to be involved in the progression of diabetic nephropathy. The aim of this study was to elucidate the effect of C-peptide and insulin as a reference on the eNOS expression in the early phase of type 1 diabetic rat kidney. METHODS: Type 1 diabetes in rats was produced by streptozotocin injection and some of the rats were treated with either C-peptide or insulin by the aid of an osmotic pump for 1 week. Conventional biochemical and histological analyses were performed on tissue samples. RESULTS: The diabetic rats showed hyperglycemia with over 90% reduction of endogenous insulin and C-peptide. Replacement with C-peptide or insulin resulted in recovery of weight lost, but only insulin infusion lowered plasma-glucose concentration. The eNOS protein was localized in glomeruli and endothelial cells of arterioles, and its amounts in the kidneys, but not in the lungs, of diabetic rats was increased. Replacement with C-peptide or insulin-abrogated diabetes-induced increase of renal eNOS protein. CONCLUSION: The results indicate that C-peptide suppresses diabetes-induced abnormal renal eNOS expression, by which C-peptide may exert beneficial effects on diabetic nephropathy.     

Increased renal glucose metabolism in Type 1 diabetes mellitus.

AIMS: In poorly controlled diabetes, increased renal glucose uptake has been implicated in the pathogenesis of diabetic nephropathy by promoting nonenzymatic glycosylation of proteins, activation of protein kinase C, and increased polyol pathway flux. However, whether glucose uptake by the diabetic kidney is actually increased, especially in patients with Type 1 diabetes, is unclear. METHODS: To examine this question, we used a combination of net balance and isotopic techniques to compare renal glucose uptake in 12 subjects with Type 1 diabetes before and after restoration of near normoglycaemia by infusion of insulin with that in 15 postabsorptive nondiabetic volunteers. RESULTS: Prior to insulin infusion, the diabetic subjects were markedly hyperglycaemic (arterial glucose 15.8 +/- 0.9 vs. 4.4 +/- 0.1 mm) and their renal tissue glucose uptake (i.e. total glucose disappearance across the kidney minus glycosuria) was increased more than 2 1/2-fold (388 +/- 43 vs. 148 +/- 12 micromol/min, P < 0.001). This was wholly explained by the mass action effects of hyperglycaemia since the diabetic subjects had normal renal blood flow (1575 +/- 82 vs. 1492 +/- 68 mL/min, P = 0.46) and reduced renal tissue glucose fractional extraction (1.7 +/- 0.2 vs. 2.3 +/- 0.1%, P = 0.027). Insulin infusion for three hours, which restored near normoglycaemia (arterial glucose 7.6 +/- 0.7 mm), reduced renal tissue glucose uptake toward normal (258 +/- 41 micromol/min, P = 0.006) without altering renal blood flow (1557 +/- 110, P = 0.63) or renal tissue glucose fractional extraction (2.1 +/- 0.3%, P = 0.35). Renal and hepatic glucose release, which had been increased (419 +/- 49 and 960 +/- 54 vs. 204 +/- 9 and 734 +/- 32 micromol/min, both P < 0.001), were suppressed by insulin to 138 +/- 22 and 520 +/- 53 micromol/min, respectively (both P < 0.001). CONCLUSIONS: In poorly controlled Type 1 diabetes, renal glucose uptake is markedly increased, which provides a link between hyperglycaemia and biochemical processes implicated in the pathogenesis of diabetic nephropathy. Its reversal by restoration of near normoglycaemia with insulin may explain the benefit of intensive insulin therapy in preventing diabetic nephropathy.     

金属蛋白酶-2和金属蛋白酶组织抑制物-1与糖尿病肾病关系的实验研究

目的　观察链脲佐菌素 (STZ)实验性糖尿病大鼠肾脏基质金属蛋白酶 2 (MMP 2 )及金属蛋白酶组织抑制物 1(TIMP 1)蛋白的表达及功能、形态学改变 ,探讨MMP 2、TIMP 1在糖尿病肾病(DN)发生机制中的意义。　方法　 2 0只雄性Wistar大鼠随机分为糖尿病组和正常对照组 ,分别于第1、2、4、6、8周测定尿白蛋白排泄率 (UAER) ,第 9周用Western印迹方法检测MMP 2、TIMP 1蛋白表达水平 ,电镜观察肾小球基底膜厚度 (GBMT)。　结果　糖尿病组较正常组TIMP 1蛋白表达明显增加 ,MMP 2蛋白表达显著降低 (P <0 .0 1)。 4、6、8周UAER显著增加 ,GBMT明显增厚 (P <0 .0 1)。电镜发现糖尿病组肾小球基底膜弥慢性增厚 ,局部有系膜细胞插入和双轨征。　结论　持续高血糖可使大鼠肾脏MMP 2下降 ,TIMP 1增加。导致肾小球基底膜增厚 ,UAER增加。MMP 2、TIMP 1失衡可能对糖尿病肾病功能和形态学改变有重要意义。     

Effect of long-term near-normoglycemia on the progression of diabetic nephropathy

The effect of prolonged restoration of near-normoglycemia on the progression of diabetic nephropathy was evaluated in a controlled study in which 10 insulin-dependent (type 1) diabetic patients with clinical proteinuria were randomized to continue with conventional insulin treatment (CIT) or to undertake more intensive diabetic therapy using continuous subcutaneous insulin infusion (CSII). The patients, mean age 33 +/- 8 yr, mean duration of diabetes 15 +/- 4 yr, were studied before and during 12 months of either CIT or CSII therapy. Glycemic control was assessed by means of mean blood glucose (MBG) +/- Standard deviation (SD), urinary glucose excretion and glycosylated hemoglobin, while renal function was assessed by albumin, IgG and beta-2-microglobulin urinary excretion rates, serum creatinine and creatinine clearance. Blood glucose level, urinary glucose excretion and glycosylated hemoglobin fell significantly in the CSII group, while no differences were found in the CIT group after the 12 months observation period. Both groups showed a deterioration in all indices of renal function, as illustrated by an increase of protein excretion rates and of serum creatinine, and by a decline in creatinine clearance. Comparison of the rate of increase of urinary albumin and IgG excretion and of serum creatinine and of the rate of fall in creatinine clearance between CIT and CSII groups demonstrated that the rate of progression of diabetic nephropathy may be slowed by correction of hyperglycemia. Our study, with due reservations because of the small number of examined patients and differences in kidney function at the beginning of the trial shows that intensive diabetic care may play a role in the proteinuric stage of diabetes in slowing further destruction of residual glomerular structure and in delaying end stage renal failure.