The Protective Effect of Vanadium Against Diabetic Cataracts in Diabetic Rat Model

The present study was designed to investigate the effect of vanadium in alloxan-induced diabetes and cataract in rats. Different doses of vanadium was administered once daily for 8 weeks to alloxan-induced diabetic rats. To know the mechanism of action of vanadium, lens malondialdehyde (MDA), protein carbonyl content, activity of superoxide dismutase (SOD), activities of aldose reductase (AR), and sorbitol levels were assayed, respectively. Supplementation of vanadium to alloxan-induced diabetic rats decreased the blood glucose levels due to hyperglycemia, inhibited the AR activity, and delayed cataract progression in a dose-dependent manner. The observed beneficial effects may be attributed to polyol pathway activation but not decreased oxidative stress. Overall, the results of this study demonstrate that vanadium could effectively reduce the alloxan-induced hyperglycemia and diabetic cataracts in rats.     

Hydrogen Sulfide Alleviates Diabetic Nephropathy in a Streptozotocin-induced Diabetic Rat Model

Accumulating evidence has demonstrated that hydrogen sulfide (H₂S) plays critical roles in the pathogenesis of chronic kidney diseases. This study was designed to investigate whether H₂S has protective effects against diabetic nephropathy. Diabetic rats were induced by intraperitoneal injection of streptozotocin and administrated with H₂S donor NaHS for 12 weeks. Rat glomerular mesangial cells were pretreated with NaHS or MAPK inhibitors (U0126, SP600125, and SB203580) prior to high glucose exposure, and cell proliferation was determined. Our findings suggest that H₂S can improve renal function and attenuate glomerular basement membrane thickening, mesangial matrix deposition, and renal interstitial fibrosis in diabetic rats. H₂S was found to reduce high glucose-induced oxidative stress by activating the Nrf2 antioxidant pathway and to exert anti-inflammatory effects by inhibiting NF-κB signaling. In addition, H₂S reduced high glucose-induced mesangial cell proliferation by blockade of MAPK signaling pathways. Moreover, H₂S was also found to inhibit the renin-angiotensin system in diabetic kidney. In conclusion, our study demonstrates that H₂S alleviates the development of diabetic nephropathy by attenuating oxidative stress and inflammation, reducing mesangial cell proliferation, and inhibiting renin-angiotensin system activity.     

The Relation Between Ion Absorption and Protein Synthesis in Beet Disks

Disks of red beet storage tissue were incubated under asepticconditions permitting the development of various metabolic processescommonly associated with aged disks, and the effects of chloramphenicoland puromycin on protein synthesis, on the development of invertaseactivity and ion absorption capacity, and on ion absorptionper se were determined. Low concentrations of chloramphenicoland puromycin inhibit the development of ion absorption capacitybut stimulate invertase development and protein synthesis, whilehigher concentrations inhibit all three processes. In contrastion absorption itself is unaffected by puromycin, but is sensitiveto quite low concentrations of chloramphenicol The D-threo andL-threo isomers of chloramphenicol have sharply contrasted effectson the development, as distinct from the utilization, of ionabsorption capacity. The D isomer inhibits the development ofion absorption capacity more effectively than the L isomer whichin turn inhibits absorption more effectively than the D isomer. A reappraisal is made of the hypothesis that ion absorptionis directly linked with protein turnover and to account forthe results a model is proposed in which D-threo-chloramphenicolis active both as an uncoupler of oxidative phosphoryalationand as an inhibitor of protein synthesis, while L-threo-chloramphenicolacts only in the former capacity and puromycin only in the latter.It is concluded that the inhibition of ion uptake by chloramphenicolcannot be attributed to a contemporaneous effect on proteinsynthesis. However, the results are consistent with the involvementof ATPase proteins in ion uptake.     

ICAM-1、TG在大鼠糖尿病性下肢溃疡中的意义

目的:研究甘油三脂(TG)、细胞问粘附分子-1(ICAM-1)在糖尿病下肢溃疡大鼠发病中的作用.方法:雄性SD大鼠腹腔注射中等剂量链脲佐菌素(STZ)同时给予高脂饮食建立糖尿病模型;8周末所有大鼠下肢涂抹冰醋酸建立糖尿病下肢溃疡模型,观察溃疡变化;12周末处死大鼠,取血测定空腹血糖、TG、胰岛素、ICAM-1和体重.结果:注射STZ后大鼠出现明显多饮、多尿症状,空腹胰岛素水平明显下降;糖尿病并溃疡组TG、ICAM-1明显高于其他组;而正常对照组与溃疡对照组各项指标无明显差异;TG与ICAM-1两者之间相关性无统计学意义.结论:ICAM-1和TG可能在糖尿病足溃疡的发生中起了重要作用.     

STZ诱导糖尿病肾病大鼠模型的建立

目的建立糖尿病大鼠动物模型,探讨其肾脏损害规律。方法用STZ65mg/kg一次性腹腔内注射方式制作糖尿病大鼠模型,设立空白对照组,饲养14周,期间观察大鼠血糖、尿糖及一般情况变化,实验结束时测定血肌酐、尿素氮、尿蛋白、尿白蛋白排泄率,取肾作病理及超微病理检查。结果模型组大鼠出现血肌酐、尿素氮、尿蛋白、尿白蛋白明显升高,出现肾脏肥大,病理显示明显的肾小球、肾小管病变。结论STZ诱导糖尿病大鼠肾脏表现肾小球及小管间质损害,可以用作糖尿病肾病研究的动物模型。     

延长糖尿病模型大鼠生存期对糖尿病视网膜病变的影响

目的延长糖尿病模型大鼠生存期,动态观察糖尿病视网膜病变(DR)的形成和发展过程。方法雄性SD大鼠70只,随机分成对照组(20只)和模型组(50只),采用链脲佐菌素(STZ)60 mg/(kg.bw)体重腹腔1次注射造模,分别于69、、12月时处死取眼球,采用视网膜微血管消化铺片技术观察糖尿病视网膜病变的微血管形态学改变。结果糖尿病大鼠DR样病变随着病程的延长病变呈多样性改变,以12月DR出现的小动脉硬化尤为严重。结论糖尿病大鼠生存期的延长对糖尿病视网膜病变的研究有着积极的意义。     

氢气与肠道菌群的关系研究进展

目前,氢气已被证实在多种疾病中具有显著的医学效应,然而其发挥效应的分子机制并不清楚。肠道菌群被人们看作人体的一个重要“器官”,与人类健康的关系密不可分。研究表明,人类肠道菌群中存在着大量能够进行氢气代谢的菌群,这些菌群的变化可能与多种疾病的发生发展密切相关。此外,研究还发现外源氢气干预可能通过重塑肠道菌群改善炎症性肠病、脂肪性肝病等。综述了肠道菌群的氢气代谢及其与疾病发生发展的关系以及外源氢气干预通过调节肠道菌群影响疾病进展的相关研究,希望能为致力于从肠道菌群角度研究氢气医学效应的科研工作者提供帮助。     

An Enhanced Intestinal Absorption of Calcium in the Rat Directly Attributed to Dietary Casein

The whole-body burdens and concentrations of ZDDT (the sum of p,p,′-DDE and p,p′-DDT) and PCBs in the Weddell seal, Leptonychotes weddelli, caught near Syowa Station, Antarctica, were determined by detailed biometric measurements of their organs and tissues and analyses of ZDDT and PCBs in them. The concentration levels of ZDDT and PCBs in Weddell seals were much lower than those in various species of marine mammals from other oceans. The low levels may be attributable to the low concentration of these chemicals in the food of Weddell seals and in the sea water under antarctic fast ice. However, the concentration ratio of ZDDT between the food organisms of seals and sea water under antarctic fast ice was higher than those of other ocean ecosystems.     

Urinary Protein Profiles in a Rat Model for Diabetic Complications

Diabetes mellitus is estimated to affect ∼24 million people in the United States and more than 150 million people worldwide. There are numerous end organ complications of diabetes, the onset of which can be delayed by early diagnosis and treatment. Although assays for diabetes are well founded, tests for its complications lack sufficient specificity and sensitivity to adequately guide these treatment options. In our study, we employed a streptozotocin-induced rat model of diabetes to determine changes in urinary protein profiles that occur during the initial response to the attendant hyperglycemia (e.g. the first two months) with the goal of developing a reliable and reproducible method of analyzing multiple urine samples as well as providing clues to early markers of disease progression. After filtration and buffer exchange, urinary proteins were digested with a specific protease, and the relative amounts of several thousand peptides were compared across rat urine samples representing various times after administration of drug or sham control. Extensive data analysis, including imputation of missing values and normalization of all data was followed by ANOVA analysis to discover peptides that were significantly changing as a function of time, treatment and interaction of the two variables. The data demonstrated significant differences in protein abundance in urine before observable pathophysiological changes occur in this animal model and as function of the measured variables. These included decreases in relative abundance of major urinary protein precursor and increases in pro-alpha collagen, the expression of which is known to be regulated by circulating levels of insulin and/or glucose. Peptides from these proteins represent potential biomarkers, which can be used to stage urogenital complications from diabetes. The expression changes of a pro-alpha 1 collagen peptide was also confirmed via selected reaction monitoring.Diabetic nephropathy (DNP)¹ accounts for ∼44% of new cases of end stage renal disease (ESRD) (1). This high morbidity is the result of the impact of a growing population and longer life expectancy. With an increase in the prevalence of DM and a corresponding reduction in the mortality associated with both type 1 and type 2 DM, patients are living longer and are therefore at higher risk to develop complications such as nephropathy (2). Moreover, Type 1 DM patients who progress to ESRD have a substantial risk of mortality with estimated annual health care costs in the United States to be approximately $1.9 billion (3, 4). Two key therapies for the prevention and management of ESRD are aggressive glycemic control and blood pressure regulation (5, 6). Early intervention is essential in reducing the severity and course of this complication (6), and changes in urine biomarkers have historically been used to diagnose and monitor disease progression. In addition, urine represents a desirable matrix in which to detect biomarkers of nephropathy as urinary protein excretion profiles are reflective of functional changes within the kidney, such as glomerular filtration rate. Clinical determinations of urinary total protein and urinary albumin excretion are commonly used measurements to monitor and/or determine the onset of diabetic nephropathy. Unfortunately, these measurements often lead to improper diagnoses for at risk DM patients (7, 8). Therefore, new prognostic indicators are required to accurately target these patients for therapeutic intervention earlier in the course of the disease as well as identify patients who are unlikely to progress, as therapy may be of little or no benefit to them.Utilizing experimental models to study the pathophysiological changes that occur as function of disease progression has provided an approach for biomarker discovery. In diabetes, animal models have been widely used in the investigation of the progression of diabetes complications such as nephropathy. Research conducted on the association between hyperglycemia and microvascular disease in diabetes as well as the study of the effect of extracellular matrix protein expression on changes in morphology in the diabetic kidney are two such examples (9). In addition, these models have assisted in developing appropriate clinical trials for the prevention and treatment of these complications. One such example is the use of anti-hypertensive treatment regimes in genetically hypertensive rats; these have examined whether early intervention may be renoprotective and therefore delay or prevent the onset of diabetic nephropathy (10–12).STZ-induced hyperglycemia in rodents is the most extensively studied model of diabetic nephropathy and associated complications (9, 13). Hyperglycemia occurs in this model because of the toxin''s destruction of pancreatic Beta-islet cells, which are essential to the production of insulin. STZ-induced hyperglycemia is associated with reliable and consistent structural and functional deficits in specific urogenital organ function (i.e. kidney and bladder). Increased glomerular filtration and hypertrophy, as well as increased urgency and morphology changes, are structural and functional abnormalities that have been observed in the kidney and bladder, respectively, in both in humans and the STZ rat model (14–19).Currently, there are two primary methods used to monitor disease progression in diabetes. The measurement of urinary albumin excretion rates and total protein concentration are routinely used to monitor disease progression as they reflect structural and functional changes in the kidney. Measurements of albumin by immunochemical assays and size exclusion high performance liquid chromatography are routinely employed (7). However, urine consists of a multitude of proteins, many of which are also reflective of pathophysiological changes because of DM urogenital complications (20–23). Proteomics provides a powerful approach for the detection of urinary protein changes as a result of disease, and multiple proteomic techniques are available in large scale protein profiling to discover new biomarkers (24–26). To date, proteomic strategies for biomarker discovery in urine have primarily included top-down approaches, for example two-dimensional gel electrophoresis coupled with mass spectrometry and/or surface enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF-MS) analyses (27–30). In addition a number of studies using capillary electrophoresis mass spectrometry, which have a number of advantages for analysis of urine, have been successfully carried out (31–33). While these approaches can easily detect and quantify a variety of proteinaceous species including isoforms, posttranslational modifications, or degradation products, other methods could be used to expand the number of proteins that are both quantified and identified providing an expanded set of biological targets to understand the complications of disease and its progression. Recent advances in both chromatography and mass spectrometry have enabled bottom-up approaches that identify and quantify at the peptide level (34–36). One advantage of bottom-up proteomics is increased overall proteome coverage. Moreover, most bottom-up methods provide both qualitative and quantitative data in a single run, and quantifying at the peptide level leads directly into a bottom-up confirmation/validation analysis thereby avoiding the peptide selection step in this procedure. Approaches to bottom-up proteomics include specific peptide labeling or label-free analysis. Specific labeling approaches such as isobaric tag for relative and absolute quantification (iTRAQ) and ¹⁸O employ differential stable isotope labeling strategies that create specific mass tags for different samples, which are mixed and then identified and quantified using mass spectrometry (37). The utility of these techniques is that they accommodate a wide range of pre-fractionation strategies thereby improving proteome coverage.The label-free approach capitalizes on the highly reproducible chromatography and high mass accuracy available in current LC/MS systems. This method observes all detectable peptides and if interrogated by MS/MS their corresponding fragment ions. This approach quantifies a peptide by its intensity and groups each peptide across individual samples based on its accurate mass and retention time (38, 39). These intensities associated with specific mass and retention time values are organized into peptide array tables that may be further processed using statistical techniques that accommodate high-dimensional data. As with other bottom-up approaches, this method is also amenable to pre-fractionation strategies, but unlike labeled approaches, the removal of chemical or metabolic labeling steps simplifies the overall approach.Here we use a comparative label-free LC/MS/MS approach to identify and rank candidate biomarkers of urogenital complications from an STZ rat model of diabetes. We describe further technical validation of our approach by confirming the changes observed with the putative biomarker, pro-alpha (2) with an alternative method: selected reaction monitoring (SRM).     

KGF Phage Model Peptide Accelerates Cutaneous Wound Healing in a Diabetic Rat Model

International Journal of Peptide Research and Therapeutics - The authors have previously demonstrated that one phage-displayed keratinocyte growth factor (KGF) model peptide that can bind to...     

大鼠糖尿病溃疡动物模型的初步研究

目的构建大鼠糖尿病溃疡动物模型,观察评价该模型的临床及病理特点。方法利用磁片循环压迫的方法,构建大鼠糖尿病溃疡动物模型,并从整体,组织和生化三个层次对糖尿病溃疡进行了研究。结果构建出了一个可以复制的糖尿病溃疡动物模型,该模型具有组织坏死、白细胞聚集以及高浓度晚期糖化终末产物等特征。结论利用缺血再灌注法构建了大鼠糖尿病溃疡动物模型。其病理改变与人极为相似,是一种很好的用于糖尿病溃疡发病机制和治疗研究的动物模型。     

饮食胆固醇吸收的研究进展

膜蛋白尼曼-匹克C1型类似蛋白1(Niemann-Pick C1 Like 1,NPC1L1)是介导肝脏和小肠细胞从胆汁或食物中吸收胆固醇的关键蛋白质。本文综述了NPC1L1蛋白的结构、功能及其介导肝肠细胞吸收外源胆固醇的分子机制。NPC1L1蛋白与脂筏蛋白Flotillin-1或Flotillin-2结合,在细胞质膜上形成富含胆固醇的膜微结构域,通过clathrin/AP2介导的囊泡内吞机制,将该NPC1L1-Flotillin-Cholesterol膜微结构域内吞运输至细胞内的内吞循环体上;内吞循环体上的胆固醇浓度下降后,NPC1L1-Flotillin复合物则由Cdc42和Myosin Vb.Rab11a.Rab11-FIP2蛋白运输至质膜,以执行下一轮的胆固醇吸收功能。NPC1L1蛋白的N端结构域可特异性结合胆固醇,是NPC1L1-Flotillin-Cholesterol膜微结构域形成所必需的,同时决定了胆固醇吸收的特异性。人群中NPC1L1基因的多态性与胆固醇吸收异常相关。本文还对未来的研究方向进行了探讨。     

Relationship Between Protein Synthesis and Viral Deoxyribonucleic Acid Synthesis

Evidence is presented that poxvirus deoxyribonucleic acid (DNA) synthesis required concurrent protein synthesis. The protein requirement in question can be distinguished from viral-induced thymidine kinase and DNA polymerase by virture of the instability of its messenger ribonucleic acid and its stoichiometric rather than catalytic relation to DNA synthesis. The protein(s) required did accumulate in the presence of fluorodeoxyuridine, an inhibitor of DNA synthesis, and, thus, appeared to be an "early" poxvirus function. The protein(s) was stable since it did function several hours after its synthesis had been terminated by puromycin. Two possible roles for such a protein requirement are discussed.     

Relationship Between Catechol-O-Methyltransferase and Phenolsulfotransferase in the Metabolism of Dopamine in the Rat Brain

The relationship between phenolsulfotransferase (PST) and catechol-O-methyltransferase (COMT) in the metabolism of free 3,4-dihydroxyphenylethylamine (DA, dopamine) in the rat brain was studied. In rats not pretreated with a monoamine oxidase (MAO) inhibitor a huge increase of free DA in the brain, following an intraperitoneal injection of L-3,4-dihydroxyphenylalanine (L-DOPA) or an intraventricular injection of free DA, did not lead to any noticeable change in DA sulfate or 3-methoxytyramine (3-MT), which remained undetectable by the present HPLC method. However, in rats previously treated with the MAO inhibitors pargyline or tranylcypromine, the same L-DOPA or free DA treatment resulted in significant increases in both 3-MT and DA sulfate in the hypothalamus, brainstem, and striatum. This response of COMT and PST was not affected by prior treatment of the rats with 6-hydroxydopamine, which suggests that O-methylation and sulfoconjugation occur outside adrenergic neurons not destroyed by the neurotoxin. Inhibition of COMT activity did not lead to any increase in DA sulfate, which showed that despite their common mode of action (both enzymes react preferentially at the same hydroxyl group in the DA molecule), the two enzymes are not competitive. After MAO inhibition there were strong correlations between an increase in DA sulfate and 3-MT on the one hand, and between free DA and 3-MT on the other. Because 3-MT is a marker of central DA release, these data suggest that inhibition of MAO activity not only affects DA metabolism by this enzyme but also influences DA release in the rat brain.     

Vasoactive Intestinal Peptide Increases Acetylcholine Synthesis by Rat Hippocampal Slices

The purpose of this study was to determine whether vasoactive intestinal peptide (VIP) might have a presynaptic modulatory effect at cholinergic terminals in the rat hippocampal formation. The exposure of rat hippocampal slices to VIP increased [3H]acetylcholine ([3H]ACh) synthesis from the precursor [3H]choline when tissue was incubated in normal or in high K+ medium; the maximal effect was apparent at 10(-8) M VIP and 10(-7) M VIP, respectively. Also, 10(-7) M VIP increased the activity of choline acetyltransferase (ChAT) in a hippocampal homogenate system. The increased synthesis by hippocampal slices was not the result of a VIP-induced alteration in either the basal release of ACh or the uptake of choline via the high-affinity uptake system. The increase in ACh synthesis induced by VIP in hippocampal slices was not associated with either adenylate cyclase or protein kinase C second messenger systems. There was no correlation between the effect of VIP on cyclic AMP production with that on ACh synthesis; also, forskolin, an activator of adenylate cyclase that increased cyclic AMP production 3.5-fold, did not mimic the effect of VIP on ACh synthesis. Similarly, there was no effect of the protein kinase C activator, phorbol myristate acetate, on ACh synthesis in hippocampal slices. However, the effect of VIP to increase ACh synthesis was not evident in the absence of extracellular calcium, suggesting that the effect of VIP is mediated by a calcium-requiring mechanism. The results suggest that, in the rat hippocampus, VIP has a presynaptic action at cholinergic terminals that results in enhanced synthesis of ACh, possibly by an action that alters ChAT activity.     

2型糖尿病大鼠模型的建立及其糖代谢特征分析

目的　建立一种接近于人类普通型 2型糖尿病大鼠模型。方法　 8周龄SD大鼠高热量饮食喂养 2个月后给予小剂量STZ建立 2型糖尿病模型 ,然后进行胰岛素 葡萄糖耐量试验、胰岛免疫组化及其图像分析 ,并与大、小剂量STZ、单纯高热量饮食等各组大鼠相应指标比较。结果　高热量饮食一段时间后给予小剂量STZ的大鼠模型外周胰岛素敏感性降低 ,胰岛素合成和分泌相对于单纯高热量饮食组大鼠降低 ,但仍高于正常对照组。结论　该模型大鼠具有外周胰岛素抵抗和胰岛功能仅轻微受损等特征 ,具有类似人类 2型糖尿病的临床表现 ,有助于该病及其慢性并发症发病机理的研究     

Cellular Cholesterol Transport Proteins in Diabetic Nephropathy

Background

Lipid accumulation has been shown to accelerate renal injury, and the intracellular accumulation of lipids may be caused by alterations in synthesis as well as lipid uptake and efflux. We have investigated the role of cellular cholesterol transport proteins including adenosine triphosphate binding cassette transporter A1 (ABCA1), G1 (ABCG1) and scavenger receptor class B type I (SR-BI) in diabetic nephropathy.

Methods

Protein expression and the ability to mediate cholesterol efflux of ABCA1, ABCG1 and SR-BI was determined in human renal mesangial cells and proximal tubular epithelial cells cultured under normal or high glucose conditions. Renal expression of these cholesterol transporters was examined in a murine model of streptozotocin-induced type 1 diabetes.

Results

ABCA1, ABCG1 and SR-BI were expressed in both human renal mesangial cells and proximal tubular epithelial cells, and mediated cholesterol efflux to apolipoprotein AI and HDL. In vitro, hyperglycemia reduced the expression and the ability to mediate cholesterol efflux of all three cholesterol transporters (p<0.05). In vivo studies showed that intra-renal accumulation of lipids was increased in diabetic mice, particularly in mice with nephropathy. This was associated with a significant reduction in the expression of ABCA1, ABCG1 and SR-BI in the kidneys. These changes were already seen in diabetic mice without nephropathy and preceded the development of nephropathy. Diabetic mice with nephropathy had the lowest level of these cholesterol transporters.

Conclusion

Inducing diabetes with streptozotocin significantly reduced renal expression of ABCA1, ABCG1 and SR-BI. Defects in cholesterol export pathway in renal cells could therefore promote cholesterol accumulation and might contribute to the development of diabetic nephropathy.     

Efficacy of Biodegradable Curcumin Nanoparticles in Delaying Cataract in Diabetic Rat Model

Curcumin, the active principle present in the yellow spice turmeric, has been shown to exhibit various pharmacological actions such as antioxidant, anti-inflammatory, antimicrobial, and anti-carcinogenic activities. Previously we have reported that dietary curcumin delays diabetes-induced cataract in rats. However, low peroral bioavailability is a major limiting factor for the success of clinical utilization of curcumin. In this study, we have administered curcumin encapsulated nanoparticles in streptozotocin (STZ) induced diabetic cataract model. Oral administration of 2 mg/day nanocurcumin was significantly more effective than curcumin in delaying diabetic cataracts in rats. The significant delay in progression of diabetic cataract by nanocurcumin is attributed to its ability to intervene the biochemical pathways of disease progression such as protein insolubilization, polyol pathway, protein glycation, crystallin distribution and oxidative stress. The enhanced performance of nanocurcumin can be attributed probably to its improved oral bioavailability. Together, the results of the present study demonstrate the potential of nanocurcumin in managing diabetic cataract.