Repression of Polyol Pathway Activity by Hemidesmus indicus var.pubescens R.Br.Linn Root Extract,an Aldose Reductase Inhibitor:An In Silico and Ex Vivo Study

Development of diabetic cataract is mainly associated with the accumulation of sorbitol via the polyol pathway through the action of Aldose reductase(AR).Hence,AR inhibitors are considered as potential agents in the management of diabetic cataract.This study explored the AR inhibition potential of Hemidesmus indicus var.pubescens root extract by in silico and ex vivo methods.Molecular docking studies(Auto Dock tool)betweenβ-sitosterol,hemidesminine,hemidesmin-1,hemidesmin-2,and AR showed thatβ-sitosterol(−10.2 kcal/mol)and hemidesmin-2(−8.07 kcal/mol)had the strongest affinity to AR enzyme.Ex vivo studies were performed by incubating isolated goat lenses in artificial aqueous humor using galactose(55 mM)as cataract inducing agent at room temperature(pH 7.8)for 72 h.After treatment with Vitamin E acetate−100μg/mL(standard)and test extract(500 and 1000μg/mL)separately,the estimation of biochemical markers showed inhibition of lens AR activity and decreased sorbitol levels.Additionally,extract also normalized the levels of antioxidant markers like SOD,CAT,GSH.Our results showed evidence that H.indicus var.pubescens root was able to prevent cataract by prevention of opacification and formation of polyols that underlines its potential as a possible therapeutic agent against diabetic complications.

Astragalin attenuates diabetic cataracts via inhibiting aldose reductase activity in rats

AIM:To investigate the aldose reductase(AR)inhibition capacity of astragalin(AST)against streptozoticin-induced diabetic cataracts(DCs)in rats.METHODS:Ex vivo investigations were conducted by treating the lens of a goat placed for 72h in artificial aqueous humor(AAH)of pH 7.8 at room temperature with cataract-causing substance(55 mmol/L of galactose)and in vivo studies were performed on rats via induction with streptozotocin.AST was administered at different dose levels and scrutinize for DC activity.RESULTS:In diabetic rats,AST improved the body weight,blood insulin,and glucose as well as the levels of galactitol in a dose-dependent way,other biochemical parameters i.e.inflammatory mediators and cytokines,and also suppress AR activity.The level of the antioxidant parameters such as superoxide dismutase(SOD),catalase(CAT),and glutathione(GSH)activity were also altered on a diabetic lens after the administration of the AST.CONCLUSION:AST protects against lens opacification to avoid cataracts and polyols formation,indicating that it could be used as a potential therapeutic agent for diabetes.

Inhibition Effects of Salvianolic Acid M and Rosmarinic Acid in Salvia deserta Schang on Human Aldose Reductase

[Objectives]This study aimed to investigate the inhibition effects of two chemical constituents in Salvia deserta Schang on human aldose reductase( AR). [Methods]The isolated salvianolic acid M and rosmarinic acid were prepared into different concentrations of solutions for in vitro enzyme kinetics experiments. [Results]Salvianolic acid M and rosmarinic acid had the strongest inhibition effects at the concentration of 1 g/L. [Conclusions]Salvianolic acid M and rosmarinic acid have inhibition effects on human aldose reductase. The IC50 of salvianolic acid M is 0. 79 μg/mL,and that of rosmarinic acid is 1. 13 μg/mL.

Potential utility of aldose reductase-deficient Schwann cells IKARS1 for the study of axonal degeneration and regeneration

Diabetic peripheral neuropathy（DPN）is one of the most common and intractable complications of diabetes mellitus.Its irritating symptoms,such as paresthesia,hyperalgesia and allodynia,can be causes of insomnia and depression;whereas its progression to more advanced stages can result in serious consequences,such as lower limb amputations and lethal arrhythmias.

Inhibitory effect of two Indian medicinal plants on aldose reductase of rat lens in vitro

Objective:To assesse the inhibitor) effect of alcoholic extract of two Indian medicinal plants namely Ceasalpinia digyna Rottler and.Alangium lamarckii Thwaits on aldose reductase（AR） of rat lens.Methods:Rats lens were enucleated through posterior approach and their homogenate was prepared and centrifuged to obtain a clear supernatant for the determination of AR activity and protein content.Results:The alcoholic extract of Ceasalpirda digyna and Alangium lamarckii had a potent inhibitory effect on the lens AR enzyme.The IC50 values of alcoholic extract of the selected plants were calculated and were（46.29±11.17） and（106.00±5.11）μg/mL,respectively. Quercetin was used as a positive control and its IC50 value was（2.95±1.53）μg/mL.Conclusions:Thus,it is concluded that alcoholic extracts of the selected plant exhibit significant inhibitory effects on AR in the rat lens in vitro.

Evaluation of in vitro aldose reductase inhibitory potential of different fraction of Hybanthus enneaspermus Linn F.Muell

Objective:To evaluate the aldose reductase inhibitory(ARI)activity of different fractions of Hybanthus enneaspermus for potential use in diabetic cataract.Methods:Total phenol and flavonoid content of different fractions was determined.ARI activity of different fractions in rat lens was investigated in vitro.Results:The results showed significant level of phenolic and flavonoid content in ethyl acetate fraction[total phenol(212.15±0.79 mg/g),total flavonoid(39.11±2.27mg/g)]and aqueous fraction[total phenol(140.62±0.57mg/g),total flavonoid(26.07±1.49 mg/g)]as compared with the chloroform fraction[total phenol(68.56±0.51mg/g),total flavonoid(13.41±0.82mg/g)]and petrolium ether fraction[total phenol(36.68±0.43mg/g),total flavonoid(11.55±1.06mg/g)].There was a significant difference in the ARI activity of each fraction,and it was found to be the highest in ethyl acetate fraction[IC_(50)(49.26±1.76μg/mL)]followed by aqueous extract[IC_(50)(70.83±2.82μg/mL)]and it was least in the petroleum ether fraction[IC_(50)(118.89±0.71μg/mL)].Chloroform fraction showed moderate activity[IC_(50)(98.52±1.80μg/mL)].Conclusions:Different fractions showed significanct amount of ARI activity,where in ethyl acetate fraction it was found to be maximum which may be due to its high phenolic and flavonoid content.The extract after further evaluation may be used in the treatment of diabetic cataract.

Association of C(-106)T Polymorphism in Aldose Reductase Gene with Diabetic Retinopathy in Chinese Patients with Type 2 Diabetes Mellitus

Objective To identify the possible association between C（-106）T polymorphism of the aldose reductase （ALR） gene and diabetic retinopathy （DR） in a cohort of Chinese patients with type 2 diabetes mellitus （T2DM）. Methods From November 2009 to September 2010, patients with T2DM were recruited and assigned to DR group or diabetic without retinopathy （DWR） group according to the duration of diabetes and the grading of 7-field fundus color photographs of both eyes. Genotypes of the C（-106）T polymorphism （rs759853） in ALR gene were analyzed using the MassARRAY genotyping system and an association study was performed. Results A total of 268 T2DM patients （129 in the DR group and 139 in the DWR group） were included in this study. No statistically significant differences were observed between the 2 groups in the age of diabetes onset （P=0.10） and gender （P=0.78）. The success rate of genotyping for the study subjects was 99.6% （267/268）, with one case of failure in the DR group. The frequencies of the T allele in the C（-106）T polymorphism were 16.0% （41/256） in the DR group and 19.4% （54/278） in the DWR group （P=0.36）. There was no signit^cant difference in the C（-106）T genotypes between the 2 groups （P=0.40）. Compared with the wild-type genotype, odds ratio （OR） for the risk of DR was 0.7 （95% CI, 0.38-1.3） for the heterozygous CT genotype and 0.76 （95% CI, 0.18-3.25） for the homozygous TT genotype. The risk of DR was positively associated with microalbuminuria （OR=4.61; 95% CI, 2.34-9.05） and insulin therapy （OR=3.43; 95% CI, 1.94-6.09）. Conclusions Microalbuminuria and insulin therapy are associated with the risk of DR in Chinese patients with T2DM. C（-106）T polymorphism of the ALR gene may not be significantly associated with DR in Chinese patients with T2DM.

Diallyl sulfide protects against N-nitrosodiethylamine-induced liver tumorigenesis:Role of aldose reductase

AIM: To evaluate the protective effect of diallyl sulfide (DAS) against N-nitrosodiethylamine (NDEA)-induced liver carcinogenesis.METHODS: Male Wistar rats received either NDEA or NDEA together with DAS as protection.Liver energy metabolism was assessed in terms of lactate,pyruvate,lactate/pyruvate,ATP levels,lactate dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G6PD) activities.In addition,membrane disintegration of the liver cells was evaluated by measuring lipid-peroxidation products,measured as malondialdehyde (MDA); nitric oxide (NO) levels; glucose-6-phosphatase (G6Pase),catalase (CAT) and superoxide dismutase (SOD) activities.Liver DNA level,glutathione-S-transferase (GST) and cytochrome c oxidase activities were used as DNA fragmentation indices.Aldose reductase (AR) activity was measured as an index for cancer cells resistant to chemotherapy and histopathological examination was performed on liver sections from different groups.RESULTS: NDEA significantly disturbed liver functions and most of the aforementioned indices.Treatment with DAS significantly restored liver functions and hepatocellular integrity; improved parameters of energy metabolism and suppressed free-radical generation.CONCLUSION: We provide evidence that DAS exerts a protective role on liver functions and tissue integrity in face of enhanced tumorigenesis caused by NDEA,as well as improving cancer-cell sensitivity to chemotherapy.This is mediated through combating oxidative stress of free radicals,improving the energy metabolic state of the cell,and enhancing the activity of G6Pase,GST and AR enzymes.

Analysis of apigenin in <i>Blumea balsamifera</i>Linn DC. and its inhibitory activity against aldose reductase in rat lens

To investigate the therapeutic potentials of na- tural sources, stepwise polarity fractions of Blumea balsamifera were tested for their ability to inhibit aldose reductase (AR) activity in rat lenses. Of these, the ethyl acetate (EtOAc) fraction exhibited a unique AR inhibitory activity (IC50 value, 0.11 μg/mL). Apigenin was identified from the active EtOAc fraction and exhibited high AR inhibitory activity (IC50 value, 4.03 μM). The content of apigenin was measured in B. balsamifera (0.47 mg/g) by HPLC/UV analysis. Our result suggests that B. balsamifera could be a useful natural source for the development of a novel AR inhibitory agent against diabetic complications.

Reducing host aldose reductase activity promotes neuronal differentiation of transplanted neural stem cells at spinal cord injury sites and facilitates locomotion recovery

Neural stem cell(NSC)transplantation is a promising strategy for replacing lost neurons following spinal cord injury.However,the survival and differentiation of transplanted NSCs is limited,possibly owing to the neurotoxic inflammatory microenvironment.Because of the important role of glucose metabolism in M1/M2 polarization of microglia/macrophages,we hypothesized that altering the phenotype of microglia/macrophages by regulating the activity of aldose reductase(AR),a key enzyme in the polyol pathway of glucose metabolism,would provide a more beneficial microenvironment for NSC survival and differentiation.Here,we reveal that inhibition of host AR promoted the polarization of microglia/macrophages toward the M2 phenotype in lesioned spinal cord injuries.M2 macrophages promoted the differentiation of NSCs into neurons in vitro.Transplantation of NSCs into injured spinal cords either deficient in AR or treated with the AR inhibitor sorbinil promoted the survival and neuronal differentiation of NSCs at the injured spinal cord site and contributed to locomotor functional recovery.Our findings suggest that inhibition of host AR activity is beneficial in enhancing the survival and neuronal differentiation of transplanted NSCs and shows potential as a treatment of spinal cord injury.

INHIBITION OF RAT LENS ALDOSE REDUCTASE BY QUERCETAGETIN AND PATULETIN

In this paper the results of inhibition of the Aldose reductase(AR) activity on Wistar rat lens by Quercetagetin extracted from Tagetes erects Linn and by Patuletin extracted from Tagetes patula Linn are reported.Quercetagetin inhibited AR of the rat lens by 93.9% at 10^(-4)M, 76.0% at 10^(-5)M and 13.3% at 10^(-6)M. Patuletin inhibited AR of the rat lens by 100% at 10^(-1)M, 80% at 10^(-5)M and 22.7% at 10^(-6)M respectively. The results show that these two flavones are lens AR Inhibitors, but further ...

Inhibitory Effects of Different Extractions of Salvia deserta Schang on Human Aldose Reductase

[Objectives] To explore whether there are natural substances that inhibit human aldose reductase in different extracts of Salvia deserta Schang.[Methods] The inhibitory activities of human aldose reductase from 28 extracts were screened.[Results] The methanol extract of roots of Salvia deserta Schang had the strongest inhibitory effect on human aldose reductase.[Conclusions] It was confirmed that Salvia deserta Schang has inhibitory effect on human aldose reductase.

糖尿病肾病患者AR基因表达量测定

对50例正常人和80名糖尿病肾病不同分期的患者进行醛糖还原酶(Aldose Reductase,AR)基因的表达量测定,提示AR基因有望成为糖尿病肾病(DN)早期诊断的生物标志物以及DN治疗上潜在的药物靶点,并且利用AR基因对DN的中医诊断进行了分子生物学验证.

醛糖还原酶(AR)基因对大鼠肾系膜细胞的转染及AR抑制剂对其增殖的影响

目的观察醛糖还原酶(AR)基因转染及AR抑制剂(ARI)对体外培养大鼠肾系膜细胞(MsC)增殖的影响。方法应用Westernblot检测转基因MsC及PDGF作用MsC后AR的表达。四唑蓝比色法(MTT法)检测细胞增殖,流式细胞术分析细胞周期,对比大鼠正常MsC和转基因MsC的生长情况,并观察ARI———Sorbinil和Zopolrestat对血小板源性生长因子(PDGF)和小牛血清(NBS)促细胞增殖作用的影响。结果①Westernblot鉴定转基因MsCAR表达较正常MsC明显增高;②转染组较正常组生长速度快;③PDGF作用MsC后可上调AR的表达;④PDGF和10%NBS均可显著刺激两组细胞的增殖,ARI可部分抑制PDGF对正常组和转染组的促增殖作用,对10%NBS,ARI可部分抑制其对转染组的促增殖作用,而对正常组无显著影响,抑制作用呈剂量依赖性。结论AR可能参与了MsC在病理状况下的过度增殖过程。

AR基因启动子区C-106T多态性与糖尿病肾病的相关性

目的 探讨染色体7q35区醛糖还原酶(AR)基因启动子区C- 10 6 T多态性与2型糖尿病肾病(DN)相关性。方法 运用聚合酶链反应限制性片段长度多态性技术(PCR- RFL P)、DNA测序技术及高浓度琼脂糖凝胶电泳分离技术对AR基因启动子区C- 10 6 T多态位点的等位基因和基因型进行了检测,将2型DM患者139例,按尿微量白蛋白排泄率(UAER)分为早期DN组(DN+组,6 1例)和非DN组(DN-组,78例)两个亚组,并以6 3例健康成人作为对照(CON组)。结果 AR基因启动子区C- 10 6 T多态位点存在T、C两种等位基因和CC、CT、TT三种基因型,DM组和CON组间各等位基因和基因型频率差异无显著性,DN+组T等位基因和CT基因型频率明显高于DN-组和CON组(P<0 .0 5 )。结论 AR基因启动子区C- 10 6 T多态性与DN的发生、发展有关。

转ARL-1基因HepG2细胞耐药相关基因的筛选

背景与目的:醛糖还原酶相似基因1(aldose-reductaselikegene-1,ARL-1)在原发性肝癌中高表达,与肝癌细胞对化疗药物耐药有关。本研究拟建立转染ARL-1的人肝癌细胞株,观察转染ARL-1的HepG2细胞对含醛基抗肿瘤药物耐药性的改变,利用基因表达谱芯片筛选HepG2细胞转染ARL-1后差异表达耐药相关基因。方法:采用脂质体转染PBK/ARL-1质粒到HepG2细胞,获得高表达ARL-1的单克隆细胞株;RT-PCR、流式免疫荧光和免疫组化鉴定高表达ARL-1的HepG2细胞;应用MTT法和细胞凋亡分析研究HepG2细胞和转染ARL-1的HepG2细胞对含醛基抗肿瘤药物阿霉素(ADM)和丝裂霉素(MMC)的耐药性,以5-氟尿嘧啶(5-FU)(不含醛基)为对照;将Cy3和Cy5两种荧光染料分别标记两种细胞的cDNA探针,与人肝癌基因表达谱芯片进行杂交与扫描,观察转染ARL-1基因HepG2与对照组HepG2细胞在基因表达谱方面的差异,筛选耐药相关基因,并运用RT-PCR和Westernblot对部分差异表达相关基因进行初步证实。结果:与对照组HepG2细胞相比,转染ARL-1基因HepG2细胞高表达ARL-1蛋白,明显增强对含醛基的抗肿瘤药物如ADM、MMC的耐药性,分别提高2.6倍和3.47倍,用5-FU处理两组细胞,则未发现有明显的耐药差异(ADM组t=6.39,P<0.05;MMC组t=30.06,P<0.01;5-FU组t=0.684,P>0.05);芯片扫描结?

中药消癃通闭对犬前列腺组织中T、E_2、DHT、AR和5α-还原酶的影响

取前列腺增生老龄犬,经口喂给消癃通闭药粉32天后,用RIA技术测定前列腺组织中睾酮(T)、雌二醇(E_2)、双氢睾酮(DHT),并与血清中浓度对照;用Scatchard Plots方法及双复管单点法测定雄激素受体(AR);用酶学法测定5α—还原酶Ⅰ、Ⅱ型。结果发现:正常犬微粒体中5α—还原酶Ⅰ型的活性为97.145±45.729,Ⅱ型的活性为15.745±15.093(单位均为DHT Pmol/mg Pro—tein·30min^(-1),下同)。予消癃通闭lg/kg·d^(-1)组犬的测定值分别为92.454±57.703和11.328±10.060;给予消癃通闭2g/kg·d^(-1)组犬的测定值分别为42.837±31.909和9.288±11.209。各组的前列腺组织中AR的测定值无明显差异。提示消癃通闭治疗前列腺增生的机理为抑制前列腺组织中5α—还原酶的活性。

AR-GFP融合基因真核表达载体的构建及在HEK293细胞中的表达

目的:构建由绿色荧光蛋白(GFP)标记的人醛糖还原酶(AR)融合基因真核表达载体并在HEK293细胞中表达。方法:应用DNA重组技术构建AR与GFP的融合基因(AR-GFP),将AR-GFP插入pcDNA3.1/myc-HisA真核表达载体中,通过磷酸钙共沉淀转染HEK293细胞,倒置荧光显微镜评价转染效率,Western blotting技术检测AR基因在转染细胞中的整合及表达,分光光度法(UV法)测定AR表达活性,用公认的AR抑制剂(ARI)反证活性AR的存在。结果:荧光显微镜对转染细胞的观察及Western blotting结果证实AR-GFP融合蛋白在HEK293细胞中表达,UV法测活、ARI抑制试验均未证实其生物学活性。结论:转染的HEK293细胞可成功地表达AR-GFP融合蛋白,但不能成为ARI真核细胞筛选模型。

山茱萸醇提液对D-半乳糖致衰大鼠非酶糖化及AR活性的影响

目的 :研究山茱萸醇提液对 D-半乳糖致衰大鼠体内非酶糖化和醛糖还原酶活性 (AR)的影响。方法 :本实验以 D-半乳糖致衰大鼠为研究对象 ,分别以大、小剂量的山茱萸醇提液灌胃 6周 ,测定了青年大鼠、致衰大鼠糖化血清蛋白 (GSP)、糖化血红蛋白 (GHb)、胸主动脉糖基化终末产物 (AGE)含量、AR的变化 ,同时观察不同剂量山茱萸醇提液对致衰大鼠上述指标的影响。结果 :致衰大鼠 GSP、GHb、AGE含量随龄增加 ;醛糖还原酶活性增高。山茱萸醇提液可降低 GSP、GHb、AEG含量 ,对醛糖还原酶活性无明显影响。结论 :山茱萸醇提液可抑制体内蛋白质非酶糖化 。

人类ARL-1重组蛋白特异性抗体的制备及鉴定

目的 制备ARL -1重组蛋白及其特异性抗体。方法 利用基因重组技术构建PQE -ARL -1原核表达载体 ,在M15大肠杆菌中进行表达 ,制备ARL -1重组蛋白 ,再将此蛋白免疫健康新西兰兔 ,制备ARL -1特异性抗体。结果 ARL -1在大肠杆菌中获得高效表达 ,经Ni+-NTA (次氮基三乙酸 )琼脂柱纯化 ,获得纯蛋白 ,将此蛋白免疫健康新西兰兔 ,制备出抗人ARL-1特异性抗体 ,经环状沉淀试验及双琼脂扩散试验检测出抗体效价达 1∶2 0 0 0 0。结论 人类ARL -1重组蛋白及其特异性抗体的制备 ,为进一步研究ARL -1在肝癌早期诊断中的作用 。