血清糖晚期基化终末产物及可溶性晚期糖基化终末产物受体水平与急性脑梗死后出血性转化的相关性

目的 分析急性脑梗死(ACI)患者血清糖晚期基化终末产物(AGEs)、可溶性晚期糖基化终末产物受体(sRAGE)水平与脑梗死后出血性转化(HT)的相关性.方法 选取2018-01—2019-12许昌市人民医院收治的91例ACI患者为研究对象,所有患者入院后均根据病情接受个性化治疗.观察ACI后HT发生情况并分组,检测并...     

牛蒡子提取物对糖尿病大鼠作用机制的实验研究

目的:研究牛蒡子及其提取物对链脲佐菌素(STZ)糖尿病大鼠肾脏表达的影响.方法:以链脲佐菌素(STZ)诱导的糖尿病大鼠为动物模型,中药治疗组分别给予牛蒡子粉饲料、牛蒡子水提物、醇提物进行6周的实验,观察大鼠的一般状况,用免疫组化技术测定肾皮质Ⅳ型胶原、纤连蛋白(FN)的表达,荧光分光光度计检测糖基化终产物的含量.结果:牛蒡子提取物能明显改善STZ大鼠多饮、多食和体重增加减少等症状,减少肾小球PAS染色阳性基质面积比以及Col-Ⅳ、FN的表达,减轻肾脏病理损害,减轻细胞内蛋白非酶糖基化.结论:牛蒡子提取物对糖尿病大鼠肾脏病变有一定的改善,其作用机制可能与减轻细胞内蛋白非酶糖基化,影响肾小球ECM成分的合成与降解,减轻肾脏损害,减轻细胞内蛋白非酶糖化有关.研究表明:牛蒡子醇提物较其水提物和粗粉疗效更为显著.     

Detection of glycated gastric inhibitory polypeptide within the intestines of diabetic obese (ob/ob) mice

Gastric inhibitory polypeptide (GIP) is produced within endocrine cells of the small intestine and released into the circulation upon nutrient ingestion. This study has quantified the levels of this insulinotropic peptide in the intestines of lean and diabetic obese ob/ob mice and estimated the proportion that is glycated. The total intestinal GIP concentration and content of the diabetic mice were significantly greater (p < 0.01) than that of control animals. Affinity chromatographic separation and side-viewing GIP radioimmunoassay demonstrated that approx 20% of the GIP extracted from intestines of ob/ob mice was present in glycated form. Less than 2% of intestinal GIP was glycated in lean mice. In conclusion substantial quantities of glycated GIP exist within the intestines of diabetic ob/ob mice, suggesting that this may be a contributing factor to the physiological disarray of this syndrome.     

阿魏酸钠对糖尿病大鼠主动脉胶原非酶糖基化的影响

将链脲佐菌素诱发的糖尿病大鼠，以阿魏酸钠处理8周，可使糖尿病大鼠主动脉的胶原和胶原中糖基化终末产物的含量降低，其机制可能与阿魏酸钠保护抗氧化酶有关。     

High-dose thiamine therapy counters dyslipidaemia in streptozotocin-induced diabetic rats

Aims/hypothesis Cardiovascular disease in diabetes is linked to increased risk of atherosclerosis, increased levels of triglyceride-rich lipoproteins and enhanced hepatic lipogenesis. The hepatic hexosamine pathway has been implicated in signalling for de novo lipogenesis by the liver. In this study, we assessed if decrease of flux through the hexosamine pathway induced by high-dose thiamine therapy counters diabetic dyslipidaemia.Methods The model of diabetes used was the streptozotocin-induced diabetic rat with maintenance insulin therapy. Normal control and diabetic rats were studied for 24 weeks with and without oral high-dose therapy (7 and 70 mg/kg) with thiamine and benfotiamine. Plasma total cholesterol, HDL cholesterol and triglycerides were determined at 6-week intervals and hepatic metabolites and transketolase activity after death of the rats at 24 weeks.Results We found that thiamine therapy (70 mg/kg) prevented diabetes-induced increases in plasma cholesterol and triglycerides in diabetic rats but did not reverse the diabetes-induced decrease of HDL. This was achieved by prevention of thiamine depletion and decreased transketolase activity in the liver of diabetic rats. There was a concomitant decrease in hepatic UDP-N-acetylglucosamine and fatty acid synthase activity. Thiamine also normalised food intake of diabetic rats. A lower dose of thiamine (7 mg/kg) and the thiamine monophosphate prodrug benfotiamine (7 and 70 mg/kg) were ineffective.Conclusions/interpretation High-dose thiamine therapy prevented diabetic dyslipidaemia in experimental diabetes probably by suppression of food intake and hexosamine pathway signalling but other factors may also be involved. Benfotiamine was ineffective.     

晚期糖基化终产物诱导内皮细胞紧密连接改变及其机制

目的探讨晚期糖基化终产物修饰蛋白对内皮细胞紧密连接带状闭合蛋白1的形态学影响,并对其机制作初步研究。方法培养人脐静脉内皮细胞,用免疫荧光染色方法显示带状闭合蛋白1在内皮细胞分布的形态和部位。观察不同浓度和不同时间晚期糖基化终产物修饰蛋白作用下内皮细胞带状闭合蛋白1的形态学变化。研究了细胞外信号调节激酶、p38丝裂原活化蛋白激酶通路抑制剂及相关特异蛋白突变体重组腺病毒转染对晚期糖基化终产物介导的内皮细胞闭合蛋白1形态学变化的影响。结果正常对照组的内皮细胞闭合蛋白1存在于细胞周边呈环状,线条清晰连续,边缘光滑流畅,晚期糖基化终产物以时间和剂量依赖的方式引起内皮细胞紧密连接带状闭合蛋白1结构形态的改变;细胞外信号调节激酶通路抑制剂或p38丝裂原活化蛋白激酶通路抑制剂均可减轻晚期糖基化终产物对闭合蛋白1的影响;转染显性失活的细胞外信号调节激酶上游激酶MEK1和p38丝裂原活化蛋白激酶上游激酶MEK6b的重组腺病毒,均可减轻晚期糖基化终产物对带状闭合蛋白1形态的影响,而转染组成性激活的MEK1和MEK6b的重组腺病毒本身即可引起内皮细胞带状闭合蛋白1形态的变化。结论晚期糖基化终产物刺激可以引起内皮细胞紧密连接蛋白带状闭合蛋白1分布和形态的变化,这一作用可能是由细胞外信号调节激酶及p38丝裂原活化蛋白激酶信号通路介导的。     

LR-90 prevents dyslipidaemia and diabetic nephropathy in the Zucker diabetic fatty rat

Aims/hypothesis Previous studies have shown that LR-90, a new inhibitor of AGE formation, prevented the development of experimental type 1 diabetic nephropathy. In this study, we examined the effects of LR-90 in the Zucker diabetic fatty (ZDF) rat, a model of type 2 diabetes and metabolic syndrome, and investigated the mechanisms by which it may protect against renal injury. Methods Male ZDF rats were treated without or with LR-90 from age 13 to 40 weeks. Metabolic and kidney functions and renal histology were evaluated. AGE accumulation and the production of the receptor for AGE (AGER) were measured. Profibrotic growth factors, extracellular matrix proteins and intracellular signalling pathways associated with glomerular and tubular damage were also analysed. Results LR-90 dramatically reduced plasma lipids in ZDF rats, with only modest effects on hyperglycaemia. Renal AGE, AGER and lipid peroxidation were all attenuated by LR-90. LR-90 significantly retarded the increase in albuminuria and proteinuria. This was associated with reduction in glomerulosclerosis and tubulointerstitial fibrosis, concomitant with marked inhibition of renal overproduction of TGF-β1, connective tissue growth factor, fibronectin and collagen IV. Additionally, LR-90 downregulated the activation of key mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB) in the renal cortex. Conclusions/interpretation These results support our earlier studies on the renoprotective effects of LR-90 on type 1 diabetic nephropathy and provide further evidence that LR-90, an AGE inhibitor with pleiotrophic effects, may also be beneficial for the prevention of type 2 diabetic nephropathy, where multiple risk factors, such as hyperglycaemia, dyslipidaemia, obesity, insulin resistance and hypertension, contribute to renal injury. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

糖基化产物对正常大鼠尿蛋白排泄和肾脏结构的影响

目的为探讨糖基化产物对正常肾脏的特异性损害作用。方法正常大鼠静脉注射体外制备的糖基化血清蛋白（ＧＳＰ），为期２个月，观察ＧＳＰ对大鼠尿蛋白排泄、肾皮质糖基化产物和肾脏形态的影响。结果接受ＧＳＰ的大鼠血清和肾组织中糖基化终产物（ＡＧＥｓ）水平、肾小球硝基四氮唑蓝（ＮＢＴ）染色强度、尿蛋白排泄量和尿量均明显高于对照组。光学和电子显微镜观察显示，给予ＧＳＰ的大鼠肾小球体积明显增大，肾小球系膜区扩大伴有细胞外基质增加，ＰＡＳ阳性物质沉着增多和肾小球基底膜节段性增厚。结论糖基化产物能引起类似糖尿病肾病的肾脏损害。     

前纤维蛋白1在糖基化终末产物介导内皮损伤中的作用

目的通过体外培养的人脐静脉内皮细胞,探讨糖基化终末产物对内皮细胞的损伤及与前纤维蛋白1的关系。方法在体外培养的内皮细胞,分别用不同浓度(100、200、400 mg/L)糖基化终末产物孵育不同时间(6、12、24、48 h),采用Western blot检测细胞前纤维蛋白1的表达,免疫荧光染色检测前纤维蛋白1的表达和F肌动蛋白形态及分布,同时检测细胞上清液非对称性二甲基精氨酸、一氧化氮、细胞间黏附分子水平和细胞内活性氧的水平。结果糖基化终末产物呈时间依赖性上调内皮细胞前纤维蛋白1的表达,以200 mg/L糖基化终末产物作用最为明显;对照组F肌动蛋白分布在细胞周边,分布均匀,细胞间连接紧密;200 mg/L糖基化终末产物处理24 h后,细胞内F肌动蛋白形态和分布发生明显改变,同时伴有胞浆中前纤维蛋白1的表达增高;200 mg/L糖基化终末产物孵育内皮细胞24 h可显著降低一氧化氮水平,升高非对称性二甲基精氨酸、细胞间黏附分子、活性氧水平,诱导内皮细胞损伤;用siRNA干扰前纤维蛋白1表达可显著抑制糖基化终末产物诱导的内皮损伤,表现为降低细胞前纤维蛋白1的表达,明显改善F肌动蛋白的结构和分布,增加一氧化氮的生成,降低非对称性二甲基精氨酸和细胞间黏附分子的水平。结论糖基化终末产物通过上调前纤维蛋白1的表达诱导血管内皮细胞损伤。     

糖基化终末产物和磷酸化肌球蛋白轻链在糖尿病结肠动力障碍中的作用

背景:结肠动力障碍是糖尿病(DM)的常见并发症。糖基化终末产物(AGEs)在DM患者体内显著升高,然而其在DM结肠动力障碍中的作用尚未完全明确。目的:探讨AGEs和磷酸化肌球蛋白轻链(p-MLC)在DM结肠动力障碍中的作用。方法:将Sprague-Dawley大鼠随机分为DM组和正常对照组,以链脲菌素腹腔注射建立DM模型,8周后处死所有大鼠,取远端结肠组织。检测离体结肠肌条肌张力;以免疫组化染色检测结肠组织p-MLC表达;以蛋白质印迹法检测结肠组织p-MLC、总肌球蛋白轻链(t-MLC)表达。分离培养结肠平滑肌细胞(SMCs),以不同浓度、不同作用时间AGEs作用于SMCs,以蛋白质印迹法检测SMCs的p-MLC、t-MLC表达。结果:与正常对照组相比,DM组大鼠结肠平滑肌张力显著减弱[(0.89±0.09)g对(1.98±0.12)g,P0.05],DM组大鼠结肠组织pMLC/t-MLC/β-actin水平显著降低(0.98±0.10对1.61±0.12,P0.05)。SMCs经不同浓度、不同作用时间AGEs干预后,p-MLC/t-MLC/β-actin水平显著降低。结论:DM结肠动力障碍可能由AGEs抑制SMCs中MLC磷酸化所致。