Levels Of Aldose Reductase Research Articles

Hyperglycemia exacerbates cerebral ischemia/reperfusion injury by up-regulating autophagy through p53-Sesn2-AMPK pathway

Hyperglycemia exacerbates ischemic brain injury by up-regulating autophagy. However, the underlying mechanisms are unknown. This study aims to determine whether hyperglycemia activates autophagy through the p53-Sesn2-AMPK signaling pathway. Rats were subjected to 30-min middle cerebral artery occlusion (MCAO) with reperfusion for 1- and 3-day under normo- and hyperglycemic conditions; and HT22 cells were exposed to oxygen deprivation (OG) or oxygen–glucose deprivation and re-oxygenation (OGD/R) with high glucose. Autophagy inhibitors, 3-MA and ARI, were used both in vivo and in vitro. The results showed that, compared with the normoglycemia group (NG), hyperglycemia (HG) increased infarct volume and apoptosis in penumbra area, worsened neurological deficit, and augmented autophagy. after MCAO followed by 1-day reperfusion. Further, HG promoted the conversion of LC-3I to LC-3II, decreased p62, increased protein levels of aldose reductase, p53, P-p53ser15, Sesn2, AMPK and numbers of autophagosomes and autolysosomes, detected by transmission electron microscopy and mRFP-GFP-LC3 molecular probe, in the cerebral cortex after ischemia and reperfusion injury in animals or in cultured HT22 cells exposed to hypoxia with high glucose content. Finally, experiments with autophagy inhibitors 3-MA and aldose reductase inhibitor (ARI) revealed that while both inhibitors reduced the number of TUNEL positive neurons and reversed the effects of hyperglycemic ischemia on LC3 and p62, only ARI decreased the levels of p53, P-p53ser15. These results suggested that hyperglycemia might induce excessive autophagy to aggravate the brain injury resulted from I/R and that hyperglycemia might activate the p53-Sesn2-AMPK signaling pathway, in addition to the classical PI3K/AKT/mTOR autophagy pathway.

Effect of Ethanolic leaf extract of Elaeocarpus tectorius (Lour.) Poir. on Retinal Oxidative Stress in Streptozotocin-nicotinamide Induced Diabetic rats

Oxidative stress plays a crucial role in the pathogenesis of diabetic retinopathy and causes loss of vision. Elaeocarpus tectorius (Lour.) Poir. is a tree species that bears edible fruits and is traditionally used to treat diabetes. The study is aimed to investigate the ameliorative effect of ethanolic leaf extract of E. tectorius on retinal oxidative stress and aldose reductase levels in STZ-NIC-induced diabetic rats. The leaf extract was orally administered to diabetic rats once a day for about 28 days at doses of 200 and 400 mg/kg b.w. Fasting blood glucose levels were determined at regular intervals during the treatment period and retinal superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, lipid peroxidation levels and aldose reductase activity were assessed at the end of the experiment. Oral administration of E. tectorius leaf extract caused a significant decrease in the fasting blood glucose levels of diabetic rats. The extract also improved the retinal antioxidant status by increasing the levels of superoxide dismutase, catalase, glutathione peroxidase and reduced glutathione. The rate of lipid peroxidation was lowered in diabetic rats as a result of treatment with the leaf extract. The diabetic rats treated with the leaf extracts also had lower retinal aldose reductase activity when compared to the untreated diabetic rats. This study suggests that Elaeocarpus tectorius leaf extracts exhibit protective effects and improve the antioxidant status of the retina under diabetic conditions helping in the prevention and management of diabetic retinopathy.

Stimulation of Alpha-1-Adrenergic Receptor Ameliorates Obesity-Induced Cataracts by Activating Glycolysis and Inhibiting Cataract-Inducing Factors.

BackgroundObesity, the prevalence of which is increasing due to the lack of exercise and increased consumption of Westernized diets, induces various complications, including ophthalmic diseases. For example, obesity is involved in the onset of cataracts.MethodsTo clarify the effects and mechanisms of midodrine, an α1-adrenergic receptor agonist, in cataracts induced by obesity, we conducted various analytic experiments in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a rat model of obesity.ResultsMidodrine prevented cataract occurrence and improved lens clearance in OLETF rats. In the lenses of OLETF rats treated with midodrine, we observed lower levels of aldose reductase, tumor necrosis factor-α, and sorbitol, but higher levels of hexokinase, 5’-adenosine monophosphate-activated protein kinase-alpha, adenosine 5´-triphosphate, peroxisome proliferator-activated receptor-delta, peroxisome proliferator-activated receptor gamma coactivator 1-alpha, superoxide dismutase, and catalase.ConclusionThe ameliorating effects of midodrine on cataracts in the OLETF obesity rat model are exerted via the following three mechanisms: direct inhibition of the biosynthesis of sorbitol, which causes cataracts; reduction of reactive oxygen species and inflammation; and (3) stimulation of normal aerobic glycolysis.

Effect of Vitamin D on Aldose Reductase in Indonesian Diabetic Polyneuropathy Patients a Randomized Clinical Trial

Aldose Reductase (AR) is an important factor in the pathogenesis of several Diabetes Mellitus (DM) complications, including diabetic neuropathy (DN). Vitamin D has a direct effect on the pathogenesis of DN. Aldose reductase inhibition is an important element in the prevention of DM complications. The objective of this paper was to assess the effect of vitamin D on AR in Indonesian diabetic polyneuropathy (DPN) patients. This cohort study was undertaken at Haji Adam Malik General Hospital Medan, North Sumatera, Indonesia. In a double-blind, placebo-controlled, clinical trial, eligible patients were randomized to receive vitamin D 50,000 IU/week or placebo for 10 weeks. The primary end-point was mean changes of nerve conduction velocity (NCV) from baseline and after 10 weeks of supplementation. There was no significant correlation between mean changes of vitamin D and AR levels. There was significant correlation with negative direction and weak strength between mean changes of AR level and NCV of motor Tibial nerve (p<0.05; r=-0.337). There was significant correlation with positive direction and moderate strength between mean changes of vitamin D level and NCV of motor Median and Peroneal nerves, and motor and sensory Ulnar nerves (p<0.001; r=0.438 – 0.527). In conclusion, vitamin D supplementation had no effect on AR level in Indonesian DPN patients. Higher AR level was correlated with decreased NCV of motor Tibial nerve. Vitamin D supplementation improved NCV in DPN.

Chlorophytum alismifolium mitigates microvascular complications of type 2 diabetes mellitus: the involvement of oxidative stress and aldose reductase.

Chlorophytum alismifolium (C.alismifolium) tubers are used in the management of diabetes. This research evaluated the effect of ethylacetate extract of C.alismifolium (EACA) on microvascular complications and the possible association of oxidative stress and aldose reductase in type 2 diabetic rats. C.alismifolium tubers were subjected to sequential extraction until ethylacetate extract was obtained using a soxhlet apparatus. The LD50 was determined using the OECD 425 guideline. The animals were placed on high fat diet for 42days and then induced with hyperglycaemia using 40mg/kg of streptozotocin. Diabetic neuropathy was evaluated using thermal and mechanical methods. Serum was used for the assessment of oxidative stress markers and biochemical markers of retinopathy and nephropathy. Serum aldose reductase was investigated by utilizing the principle of enzyme-linked immunosorbent assay. The median lethal dose of EACA was assessed to be above 5,000mg/kg and it caused no mortality. Treatment with EACA significantly reduced the withdrawal times in both thermal and mechanical hyperalgesic methods (p<0.05). EACA also significantly reduced the levels of urea (p<0.001), albumin (p<0.05) and uric acid (p<0.001) in hyperglycaemic rats. EACA significantly decreased the amounts of low density lipoprotein and triglycerides (p<0.001). There was a remarkable elevation in the levels of high density lipoprotein (p<0.05). A significant (p<0.05) increase in the levels of magnesium was observed in the EACA-treated groups. EACA significantly increased catalase (p<0.05) and reduced malondialdehyde levels (p<0.05). The levels of aldose reductase was significantly (p<0.001) reduced by EACA compared to the hyperglycaemic control. The ethylacetate extract of C.alismifolium has beneficial effects in alleviating microvascular complications of diabetes through the inhibition of oxidative stress and aldose reductase in diabetic rats.

Chlorophytum alismifolium mitigates microvascular complications of type 2 diabetes mellitus: the involvement of oxidative stress and aldose reductase.

Chlorophytum alismifolium (C.alismifolium) tubers are used in the management of diabetes. This research evaluated the effect of ethylacetate extract of C.alismifolium (EACA) on microvascular complications and the possible association of oxidative stress and aldose reductase in type 2 diabetic rats. C.alismifolium tubers were subjected to sequential extraction until ethylacetate extract was obtained using a soxhlet apparatus. The LD50 was determined using the OECD 425 guideline. The animals were placed on high fat diet for 42days and then induced with hyperglycaemia using 40mg/kg of streptozotocin. Diabetic neuropathy was evaluated using thermal and mechanical methods. Serum was used for the assessment of oxidative stress markers and biochemical markers of retinopathy and nephropathy. Serum aldose reductase was investigated by utilizing the principle of enzyme-linked immunosorbent assay. The median lethal dose of EACA was assessed to be above 5,000mg/kg and it caused no mortality. Treatment with EACA significantly reduced the withdrawal times in both thermal and mechanical hyperalgesic methods (p<0.05). EACA also significantly reduced the levels of urea (p<0.001), albumin (p<0.05) and uric acid (p<0.001) in hyperglycaemic rats. EACA significantly decreased the amounts of low density lipoprotein and triglycerides (p<0.001). There was a remarkable elevation in the levels of high density lipoprotein (p<0.05). A significant (p<0.05) increase in the levels of magnesium was observed in the EACA-treated groups. EACA significantly increased catalase (p<0.05) and reduced malondialdehyde levels (p<0.05). The levels of aldose reductase was significantly (p<0.001) reduced by EACA compared to the hyperglycaemic control. The ethylacetate extract of C.alismifolium has beneficial effects in alleviating microvascular complications of diabetes through the inhibition of oxidative stress and aldose reductase in diabetic rats.

Diabetes-Independent Retinal Phenotypes in an Aldose Reductase Transgenic Mouse Model.

Aldose reductase (AR), the first and rate-limiting enzyme of the polyol pathway, has been implicated in the onset and development of the ocular complications of diabetes, including cataracts and retinopathy. Despite decades of research conducted to address possible mechanisms, questions still persist in understanding if or how AR contributes to imbalances leading to diabetic eye disease. To address these questions, we created a strain of transgenic mice engineered for the overexpression of human AR (AR-Tg). In the course of monitoring these animals for age-related retinal phenotypes, we observed signs of Müller cell gliosis characterized by strong immunostaining for glial fibrillary acidic protein. In addition, we observed increased staining for Iba1, consistent with an increase in the number of retinal microglia, a marker of retinal inflammation. Compared to age-matched nontransgenic controls, AR-Tg mice showed an age-dependent loss of Brn3a-positive retinal ganglion cells and an associated decrease in PERG amplitude. Both RGC-related phenotypes were rescued in animals treated with Sorbinil in drinking water. These results support the hypothesis that increased levels of AR may be a risk factor for structural and functional changes known to accompany retinopathy in humans.

Daidzein ameliorates diabetic retinopathy in experimental animals

AimThe present study was designed to check the effect of daidzein in the management of diabetic retinopathy. Main methodsStreptozotocin at dose 55 mg/kg was used for inducing diabetes in rats. After 28 days of diabetic induction, animals were treated with daidzein at dose 25, 50, and 100 mg/kg for the next 28 days. Electroretinography, estimation of plasma glucose, lactate dehydrogenase, aldose reductase, sorbitol dehydrogenase and oxidative stress parameters were performed at the end of the study. Histopathology of retina was carried out at the end of the study. Key findingsDiabetic control animals showed a significant increase in levels of plasma glucose and plasma lactate dehydrogenase (p < 0.001). Treatment with daidzein at a dose of 50 and 100 mg/kg significantly reduced the elevated level of blood glucose (p < 0.01 and p < 0.01). Whereas, treatment with daidzein at a dose 100 mg/kg significantly reduced the elevated level of lactate dehydrogenase in plasma after 28 days of treatment (p < 0.01). Treatment with daidzein at a dose of 100 mg/kg significantly reduced the level of aldose reductase and sorbitol dehydrogenase (p < 0.01 and p < 0.001 respectively). Electroretinography revealed that daidzein treatment at a dose of 100 mg/kg significantly prevented the change in ‘a’ and ‘b’ wave amplitude and latency. Oxidative stress was also found to be significantly reduced after 28 days of daidzein treatment. Histopathological findings showed a reduction in retinal thickness after daidzein treatment. SignificanceDaidzein treatment protected retina from damage in hyperglycaemic conditions. Thus, Daidzein can be considered as an effective treatment option for diabetic retinopathy.

Taxifolin Shows Anticataractogenesis and Attenuates Diabetic Retinopathy in STZ-Diabetic Rats via Suppression of Aldose Reductase, Oxidative Stress, and MAPK Signaling Pathway.

Due to the increased prevalence of diabetes-associated complications of the eye like diabetic retinopathy and cataract, the need for a novel therapeutic agent is urgent. Due to the advantages that the polyphenolic compounds enjoy in diabetes and associated complications, we postulated that Taxifolin (TXF), a poly-phenolic flavanol, could show anti-retinopathic and anti-cataract effect in diabetes-induced rats. TXF at a dose of 10, 25, and 50 mg/kg was given by oral route to STZ mediated diabetic rats for a time period of 10 weeks. The opacity of lens was studied after every 7 days of treatment till 10 weeks; evaluation of the severity of cataract and changes in the histology of lens as well as retina was done. Tissue homogenates of lens isolated after the end of the study were evaluated for markers of oxidative stress, levels of aldose reductase, p38MAPK, VEGF, and ERK1/2. Outcomes suggested that TXF improved retinopathy and cataract in diabetes-induced rats. The treatment of TXF also improved the status of oxidative stress and inhibited the levels of p38MAPK, VEGF, and ERK1/2. The treatment also improved the lens opacity in diabetic rats. The results suggest that the protective effect of TXF against cataract and retinopathy may be due to the anti-oxidative potential of TXF and its inhibiting effect on VEGF, ERK1/2, p38MAPK, and aldose reductase. The study confirms that TXF is a potential candidate showing a protective effect against diabetic induced retinopathy and cataract.

Vasant Kusmakar Ras, an ayurvedic herbo-mineral formulation prevents the development of diabetic retinopathy in rats

BackgroundDiabetic retinopathy is a slow progressing complication of diabetes mellitus with multifactorial aetiology affecting approximately 80% of diabetics worldwide. Chronic hyperglycemic milieu of Diabetes induces biochemical changes which contribute to the pathogenesis of Diabetic retinopathy. ObjectiveThe present study examined the protective effect of Vasant Kusumakar Ras, an Ayurvedic herbo-mineral formulation, in diabetic retinopathy. Materials and MethodsDiabetes was induced in rats by intraperitoneal injection of streptozotocin (45 mg/kg). Rats were kept without any treatment for period of three weeks for induction of Diabetic retinopathy followed by treatment with Vasant Kusumakar Ras (11.25 mg/kg, p.o) for further 5 weeks. Fasting blood glucose levels, lipid profile and HbA1c were determined. Eye tissue homogenates were subjected to biochemical analysis to determine the levels of oxidative stress parameters (superoxide dismutase, catalase, reduced glutathione, lipid peroxidation), vascular endothelial growth factor and aldose reductase activity. Histopathological analysis of retinal tissue was conducted using Hematoxylin and Eosin staining. ResultsVasant Kusumakar Ras treatment restored serum lipid profile which was altered in diabetic rats. Treatment with Vasant Kusumakar Ras significantly ameliorated the oxidative stress in eye tissue resulting in decreased lipid peroxidation and increase in endogenous antioxidant levels. Levels of aldose reductase and vascular endothelial growth factor in eye tissue were significantly decreased in Vasant Kusumakar Ras treated rats. Hematoxylin and Eosin staining indicated that the Vasant Kusumakar Ras treatment significantly restored the normal architecture of the retinal tissue. ConclusionVasant Kusumakar Ras exhibits protective effect and prevents the development of Diabetic retinopathy through its effects on multiple biochemical pathways implicated in pathogenesis of Diabetic retinopathy.

Protective Effect of β-Glucogallin on Damaged Cataract Against Methylglyoxal Induced Oxidative Stress in Cultured Lens Epithelial Cells.

Backgroundβ-glucogallin (GG) is one of the major plant polyphenolic antioxidants that have been associated with positive effects on human health and are crucial in the developing defense mechanism against the risk of diseases. However, reports on the protective mechanism of GG in lens epithelial cells are limited.Material/MethodsARPE-19 cells (a human retinal epithelial cell line) were exposed to methylglyoxal (MG) with or without GG to illuminate the protective role of GG in counteracting the cataract signaling.ResultsCells predisposed to MG demonstrated an increase in oxidative stress with augmented (P<0.01) inflammatory cytokines such as cyclooxygenase (COX)-2, chemokine receptor CXCR4, interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule 1 (ICAM-1) genes. In addition, the expression of aldose reductase (AR) was increased to 2-fold with accumulated sorbitol in MG exposed cells compared to control. On the other hand, cells exposed to MG evidenced a 3-fold increase in RAGE (receptor for advanced glycation end products) and a 2-fold increase in NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) expression compared to control cells. Intriguingly, lens epithelial cells pre-treated with GG attenuated the reactive oxygen species levels with improved antioxidant enzymes. Simultaneously, the levels of AR and other inflammatory cytokines were observed in the levels closer to control cells in GG pre-treated cells.ConclusionsThus, the results of the present investigation show that GG may be a potential drug for the prevention of cataract development and progression.

Increased inflammation, oxidative stress and a reduction in antioxidant defense enzymes in perivascular adipose tissue contribute to vascular dysfunction in type 2 diabetes

BackgroundPerivascular adipose tissue (PVAT) surrounds most large blood vessels and plays an important role in vascular homeostasis. The present study was conducted to investigate the contribution of PVAT to vascular dysfunction in a rat model of type 2 diabetes. Material and methodsSeveral in vivo parameters such as lipid profile (total cholesterol and triglyceride systemic levels), fasting glucose levels, glucose tolerance and insulin sensitivity (through glucose and insulin tolerance tests, respectively) were determined in Goto-Kakizaki (GK) diabetic rats and compared with control Wistar rats. At the vascular level, endothelial dependent and independent relaxation and contraction studies were performed in aortic rings in the absence (PVAT−) or in the presence (PVAT+) of thoracic PVAT. We also evaluated vascular oxidative stress and performed western blots, PCR and immunohistochemistry analysis of cytokines and various enzymes in PVAT. ResultsEndothelium-dependent relaxation to acetylcholine, assessed by wire myography, was impaired in GK rats and improved by the antioxidant TEMPOL and by the TLR4 inhibitor, CLI-095 suggesting an increase in oxidative stress and inflammation. In addition, vascular superoxide and peroxynitrite production was increased in the vascular wall of diabetic rats, accompanied by reduced nitric oxide bioavailability. The presence of PVAT had an anticontractile effect in response to phenylephrine in Wistar rats that was lost in GK rats. Western blot and immunohistochemistry analysis revealed that PVAT phenotype shifts, under diabetic conditions, towards a proinflammatory (with increment in CRP, CCL2, CD36), pro-oxidant (increased levels of aldose reductase, and reduced levels of antioxidant deference enzymes) and vasoconstriction state. ConclusionOur data suggest that this rat model of type 2 diabetes is associated with perivascular adipose dysfunction that contributes to oxidative stress, inflammation and endothelial dysfunction.

Preclinical and Clinical Proof of Concept for Metabolic Intervention in Diabetic Cardiomyopathy

Introduction Hyperactivation of the polyol pathway (PP) contributes to development of diabetic complications such as diabetic cardiomyopathy (DbCM). Aldose reductase (AR), the rate-controlling enzyme in the PP, catalyzes NADPH-dependent reduction of glucose to sorbitol. Under hyperglycemic and ischemic conditions, PP activation causes intracellular sorbitol accumulation leading to osmotic stress, cell death and diabetic complications. Previous AR inhibitors (ARI) failed due to safety or lack of efficacy. AT-001 is a novel oral ARI with optimized specificity and affinity for AR. Objectives To assess cardioprotective activity of AT-001 in an animal model of DbCM and safety, tolerability and target engagement in a phase 1/2 clinical study. Preclinical Methods and Results The cardioprotective effect of AT-100 was studied in transgenic mice expressing human levels of AR (Tg hAR) and rendered diabetic with streptozotocin (55 mg/kg for 5d). Mice were treated with AT-001 40 mg/kg, n=6 or vehicle (V, n=6) for 3d prior to cardiac ischemia reperfusion (IR) injury induced by ligation and reperfusion of the left anterior descending (LAD) coronary artery. Control non-DM Tg hAR mice (non-DM, n=9) were also subjected to IR injury. After 48h recovery mice were euthanized and infarct area and fractional shortening (FS) assessed. Mean (±SD) infarct area (ratio of infarcted to total left ventricular area) was significantly lower in AT-001 (35.3±2.7) vs. non-DM (43±2) and V (59.1±0.8); P Clinical methods and Results The phase 1/2 study consisted of single and multiple oral ascending doses (SAD, n=8 per group) of 5, 10, 20 and 40 mg/kg once daily (QD) and multiple doses (MAD) of placebo (Pbo) or AT-001 5, 20, 40 mg/kg QD or 20 mg/kg twice daily for 7d. Subjects with type 2 diabetes (T2DM), age 18-75 and HbA1c 5.0-8.5% were allocated to AT-001 (n=8) or Pbo (n=2) in each dose cohort. AT-001 was well-tolerated with no drug-related AEs. AR inhibition and target engagement were demonstrated by dose-dependent decreases in sorbitol in AT-001 (up to -50 % change from baseline) vs. Pbo subjects (-3 % change). Maximum inhibition was between 2-4 h and lasted several hours. Conclusions AT-001 significantly attenuated or prevented cardiac damage in a relevant animal model and was safe, well-tolerated and reduced sorbitol levels in T2DM subjects. These findings support clinical development in DbCM.

Protective effect of glycine in streptozotocin-induced diabetic cataract through aldose reductase inhibitory activity

Glycine is a proteinogenic amino acid that serves as a precursor for several proteins. The anti-cataract effects of lysine and other amino acid mixtures in animal models have been reported. Normal rats were administered saline and formed the normal control group (group I). Diabetic rats were administered streptozotocin and were the diabetic control group (group II). Rats were administered glycine (250 mg and 500 mg/kg of body weight) formed groups III and IV, respectively. Diabetic rats were administered sorbinil and were served as positive control (group V). The body weight changes, serum glucose, plasma insulin, total protein, glutathione (GSH) content, and mRNA and protein levels of aldose reductase were determined. Glycine treatment increased body weight gain, reduced blood glucose, and increased plasma insulin levels compared to diabetic control rats, and also increased GSH content and decreased mRNA and protein levels of aldose reductase compared to their respective controls. In summary, glycine supplementation effectively inhibited aldose reductase enzyme activity in experimental diabetic rats.

Age-related alteration in the distribution of methylglyoxal and its metabolic enzymes in the mouse brain

Methylglyoxal (MG) is an α-dicarbonyl compound that is naturally produced in vivo through glucose metabolism. In general, MG is metabolized by the glyoxalase 1(GLO1)/GLO2 system and aldose reductase (AR); however, excessive MG can react with proteins and nucleic acids to induce the accumulation of advanced glycation end products (AGEs). Recently, the accumulation of AGEs in the brain has been presumed to be related to neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease, respectively. Research investigating the role of AGEs in such diseases is ongoing. However, the changes in MG concentration that occur in the brain during healthy ageing remain unclear. Therefore, we performed fractionation of the brains of aged and young mice, measured the MG concentration in each part of the brain, and then examined the distribution. We also investigated the expression levels of GLO1 and AR, the main metabolizing enzymes of MG, in various brain regions, across age groups. We show that MG concentration varies among different regions of the brain, and that MG concentration in aged mice is significantly lower than that in young mice across all regions of the brain, except the brain stem. In addition, although the expression level of the GLO1 protein in the brain did not change with ageing, the expression level of AR was higher in aged than in young mice. Moreover, although a significant positive correlation was observed between GLO1 expression and MG concentration in the brains of young mice, no significant correlations were observed in the brains of aged mice. Meanwhile, the production of protein carbonyls and the accumulation of AGEs were not observed in the brains of aged mice. These results suggest that the accumulation of MG in the brain, along with the carbonyl stress are suppressed and regionally controlled during healthy ageing. This finding is useful as the foundation for further studies to investigate the role and toxicity of MG in various age-related disease conditions.

Composition of Ophiopogon Polysaccharide, Notoginseng Total Saponins and Rhizoma Coptidis Alkaloids Inhibits the Myocardial Apoptosis on Diabetic Atherosclerosis Rabbit.

To investigate the effects of Composition of Ophiopogon polysaccharide, Notoginseng total saponins and Rhizoma Coptidis alkaloids (CONR) on myocardial apoptosis of diabetic atherosclerosis (DA) rabbits METHODS: Sixty male New Zealand white rabbits were randomly divided into 6 groups [control group, model group, CONR high-dose group (450 mg/kg), CONR medium-dose group (150 mg/kg), CONR low-dose group (50 mg/kg), and simvastatin group] by using a completely random method, 10 in each group. DA model was established by intravenously injected alloxan combined with high-fat diet and abdominal aortic balloon injury. After mediation for 10 weeks, fasting blood glucose (FBG), glycosylated hemoglobin (GHB), glycosylated serum protein (GSP), fructoseamine (FRA), aldose reductase (AR), advanced glycation end products (AGEs) in serum were measured by enzyme linked immunosorbent assay (ELISA) method; the expression of receptor of AGEs (RAGE) in myocardial tissue were observed by immunohistochemical method; and p-Jun N-terminal kinase (p-JNK), caspase-3, B-cell lymphoma-2 (bcl-2) protein expression in myocardial tissue were measured by Western blotting. The myocardial apoptosis was detected by TdT-mediated dUTPnick-end labeling (TUNEL) method, and apoptosis index (AI) was calculated. Compared with the control group, serum FBG, GHB, GSP, FRA, AR, AGEs and the expression of myocardium RAGE, p-JNK, caspase-3 proteins, as well as apoptosis index (AI) were significantly increased and bcl-2 protein was significantly decreased in the model group (P<0.01). Compared with the model group, the levels of serum FBG, GHB, GSP, FRA and AR showed a significant decline in CONR high- and medium-dose groups (P<0.01). FBG and GHB showed a significant decline in CONR low-dose group (P<0.01). Compared with the model group, the expression of serum AGEs and myocardium RAGE, p-JNK and caspase-3 protein as well as AI were significantly decreased and bcl-2 protein was significantly up-regulated in all treatment groups (P<0.01); high-dose CONR had the most significant effect on abovementioned indices compared with other treatment groups (P<0.01). Middle-dose CONR had better effect on serum AGEs compared with the low-dose group (P<0.01); middle-dose CONR and simvastatin groups had better effect on the expression of caspase-3, bcl-2 protein, myocardium apoptosis compared with the CONR low-dose group (P<0.01). CONR may effectively inhibit myocardial apoptosis on DA rabbits by intervening AGEs-RAGE and JNK, caspase-3, and bcl-2 protein expressions.

Expression levels of aldose reductase enzyme, vascular endothelial growth factor, and intercellular adhesion molecule-1 in the anterior lens capsule of diabetic cataract patients

To compare the levels of aldose reductase (ALR) enzyme, intercellular adhesion molecule-1 (ICAM-1), and vascular endothelial growth factor (VEGF) in the anterior lens capsule of diabetic versus nondiabetic patients. Alexandria Main University Hospital, Alexandria, Egypt. Prospective case-control study. The study enrolled patients undergoing cataract extraction and divided them into 3 groups: eyes that had proliferative diabetic retinopathy (PDR), eyes that had nonproliferative diabetic retinopathy (NPDR), and nondiabetic eyes. The anterior lens capsules were obtained by performing femtosecond laser-assisted capsulorhexis. Concentrations of ALR, ICAM-1, and VEGF in the lens capsule specimens were measured using human enzyme-linked immunosorbent assay. This study comprised 200 patients (200 eyes); 51 eyes had PDR, 49 eyes had NPDR, and 100 eyes were nondiabetic. The mean ALR, ICAM-1, and VEGF levels in the anterior capsule of diabetic group were 2.84nanogram (ng)/mL±0.51 (SD), 87.73±22.84picogram (pg)/mL, and 75.53±14.95 pg/mL, respectively; whereas, in the nondiabetic group, they were 1.44±0.17ng/mL, 35.45±2.8 pg/mL, and 33.55±5.47 pg/mL, respectively. In comparing the concentrations of these mediators, both the PDR and NPDR groups had significantly higher levels compared with the nondiabetic eyes (P<.001). In addition, eyes with PDR had significantly higher levels of these mediators than eyes with NPDR (P<.001). The concentrations of ALR, ICAM-1, and VEGF in the anterior lens capsule of diabetic patients are significantly higher than those of nondiabetics. A significantly higher level of 3 mediators in eyes with PDR compared with those with NPDR might allow the use of them as a biomarker for severity of diabetic retinopathy.

Epalrestat, an Aldose Reductase Inhibitor, Restores Erectile Function in Streptozocin-induced Diabetic Rats

Epalrestat, an aldose reductase inhibitor (ARI), was adopted to improve the function of peripheral nerves in diabetic patients. The aim of this study was to investigate whether epalrestat could restore the erectile function of diabetic erectile dysfunction using a rat model. From June 2016, 24 rats were given streptozocin (STZ) to induce the diabetic rat model, and epalrestat was administered to ten diabetic erectile dysfunction (DED) rats. Intracavernous pressure (ICP) and mean systemic arterial pressure (MAP), levels of aldose reductase (AR), nerve growth factor (NGF), neuronal nitric oxide synthase (nNOS), α-smooth muscle antigen (α-SMA), and von Willebrand factor (vWF) in the corpus cavernosum were analyzed. We discovered that epalrestat acted on cavernous tissue and partly restored erectile function. NGF and nNOS levels in the corpora were increased after treatment with epalrestat. We also found that the content of α-SMA-positive smooth muscle cells and vWF-positive endothelial cells in the corpora cavernosum were declined. Accordingly, epalrestat might improve erectile function by increasing the upregulation of NGF and nNOS to restore the function of the dorsal nerve of the penis.

EFFECT OF ETHANOLIC FLOWER EXTRACT OF SPATHODEA CAMPANULATA ON STREPTOZOTOCIN INDUCED DIABETIC NEUROPATHY

Objective: To evaluate the effect of ethanolic extract of the flower of Spathodea camapanulata (EFESC) on streptozotocin-induced diabetic neuropathy.Methods: Non-insulin dependent diabetes mellitus (NIDDM) was induced in overnight fasted adult wistar strain albino male rats weighing 160-200g by a single intraperitoneal injection (i. p) of streptozotocin (STZ-65 mg/kg). The rats were randomized into six groups, with six animals each, namely normal control (NC) (Treated with 1% carboxymethyl cellulose solution), diabetic control (DC) (65 mg/kg., i. p. STZ), test group treated at various doses of EFESC250, EFESC500, and EFESC750, standard control-glibenclamide0.25 mg/kg b.w.(SCG) and the treatment has begun from the day of blood sugar level (BSL) detection after the STZ treatment. Body weight was checked daily and serum glucose levels were measured at 48 h, 15th and 28th d of study. Reaction time to thermal hyperalgesia and cold allodynia were measured after induction of diabetes. In vitro, aldose reductase inhibition assay was carried out.Results: The preliminary phytochemical screening revealed the steroids, terpenoids, coumarins, carbohydrates, tannins, glycosides, and flavonoids in EFESC. DC group showed decreased in reaction time (hyperalgesia) compared to NC while a significant increase in reaction time was observed at various doses EFESC250, EFESC500, EFESC750 and SCG0.25. EFESC at various doses showed the significant reduction in BSL and body weight on 15th and 28th d in STZ diabetic rat at various dose levels. In vitro, aldose reductase inhibition was observed with an IC50 at 131 μg/ml.Conclusion: EFESC showed reduced in BSL and prevents hyperalgesia in experimental diabetic neuropathy. It also reduced aldose-reductase level that may play an important role in reducing the complication of diabetic neuropathy.

Deficiency of aldose reductase exacerbates early pressure overload-induced cardiac dysfunction and autophagy in mice

Pathological cardiac hypertrophy is associated with the accumulation of lipid peroxidation-derived aldehydes such as 4-hydroxy-trans-2-nonenal (HNE) and acrolein in the heart. These aldehydes are metabolized via several pathways, of which aldose reductase (AR) represents a broad-specificity route for their elimination. We tested the hypothesis that by preventing aldehyde removal, AR deficiency accentuates the pathological effects of transverse aortic constriction (TAC). We found that the levels of AR in the heart were increased in mice subjected to TAC for 2 weeks. In comparison with wild-type (WT), AR-null mice showed lower ejection fraction, which was exacerbated 2 weeks after TAC. Levels of atrial natriuretic peptide and myosin heavy chain were higher in AR-null than in WT TAC hearts. Deficiency of AR decreased urinary levels of the acrolein metabolite, 3-hydroxypropylmercapturic acid. Deletion of AR did not affect the levels of the other aldehyde-metabolizing enzyme - aldehyde dehydrogenase 2 in the heart, or its urinary product - (N-Acetyl-S-(2-carboxyethyl)-l-cystiene). AR-null hearts subjected to TAC showed increased accumulation of HNE- and acrolein-modified proteins, as well as increased AMPK phosphorylation and autophagy. Superfusion with HNE led to a greater increase in p62, LC3II formation, and GFP-LC3-II punctae formation in AR-null than WT cardiac myocytes. Pharmacological inactivation of JNK decreased HNE-induced autophagy in AR-null cardiac myocytes. Collectively, these results suggest that during hypertrophy the accumulation of lipid peroxidation derived aldehydes promotes pathological remodeling via excessive autophagy, and that metabolic detoxification of these aldehydes by AR may be essential for maintaining cardiac function during early stages of pressure overload.