Aorta Of Diabetic Rats Research Articles

Icariin attenuates vascular endothelial dysfunction by inhibiting inflammation through GPER/Sirt1/HMGB1 signaling pathway in type 1 diabetic rats

Icariin, a flavonoid glycoside, is extracted from Epimedium. This study aimed to investigate the vascular protective effects of icariin in type 1 diabetic rats by inhibiting high-mobility group box 1 (HMGB1)-related inflammation and exploring its potential mechanisms. The impact of icariin on vascular dysfunction was assessed in streptozotocin (STZ)-induced diabetic rats through vascular reactivity studies. Western blotting and immunofluorescence assays were performed to measure the expressions of target proteins. The release of HMGB1 and pro-inflammation cytokines were measured by enzyme-linked immunosorbent assay (ELISA). The results revealed that icariin administration enhanced acetylcholine-induced vasodilation in the aortas of diabetic rats. It also notably reduced the release of pro-inflammatory cytokines, including interleukin-8 (IL-8), IL-6, IL-1β, and tumor necrosis factor-alpha (TNF-α) in diabetic rats and high glucose (HG)-induced human umbilical vein endothelial cells (HUVECs). The results also unveiled that the pro-inflammatory cytokines in the culture medium of HUVECs could be increased by rHMGB1. The increased release of HMGB1 and upregulated expressions of HMGB1-related inflammatory factors, including advanced glycation end products (RAGE), Toll-like receptor 4 (TLR4), and phosphorylated p65 (p-p65) in diabetic rats and HG-induced HUVECs, were remarkably suppressed by icariin. Notably, HMGB1 translocation from the nucleus to the cytoplasm in HUVECs under HG was inhibited by icariin. Meanwhile, icariin could activate G protein-coupled estrogen receptor (GPER) and sirt1. To explore the role of GPER and Sirt1 in the inhibitory effect of icariin on HMGB1 release and HMGB-induced inflammation, GPER inhibitor and Sirt1 inhibitor were used in this study. These inhibitors diminished the effects of icariin on HMGB1 release and HMGB1-induced inflammation. Specifically, the GPER inhibitor also negated the activation of Sirt1 by icariin. These findings suggest that icariin activates GPER and increases the expression of Sirt1, which in turn reduces HMGB1 translocation and release, thereby improving vascular endothelial function in type 1 diabetic rats by inhibiting inflammation.

The Roles of Potassium Channels and Nitric oxide in the Modulation of Apelin induced-relaxation in Isolated Diabetic Rat Aorta

Diabetes is associated with endothelial dysfunction, which impairs blood vesselscapacity to maintain vascular tone. Apelin is an adipocyte-produced relaxing factor that has endothelium-dependent and nitric oxide (NO)-mediated vasorelaxant effects. The current study investigated how streptozotocin (STZ)-induced type one diabetes modulates the mechanisms involved in aortic vascular response to apelin, focusing on the role of potassium channels and endothelial derived relaxing factors (EDRF). In this study, precontracted rat thoracic aortic segments were pre-incubated with the NO inhibitor, cyclooxygenase (COX) inhibitor and potassium channels blockers including: non-selective calcium-activated potassium channel, big conductance calcium-activated potassium channels (BKca), intermediate conductance calcium activated potassium channels (IKca), delayed inward rectifier potassium channels (Kir), adenosine triphosphates-sensitive potassium channels (KATP) and voltage sensitive potassium channels (Kv) blockers, then cumulative concentrations of apelin were applied to each group in both non-diabetic and diabetic conditions. The statistical analysis between diabetic and non-diabetic groups revealed that endothelial impairment induced by diabetes in rat thoracic aorta remarkably attenuated the vascular responses to apelin. An important new finding in this study was that almost all potassium channels blockers noticeably P<0.001 increased apelin efficacy with relatively no changes in the peptide potency. However, in diabetic aortic segments, the non-selective Kca, BKca blockers, NO inhibitor and COX inhibitor reversed vascular responses to apelin, but Kir, KATP and Kv blockers significantly reduced vascular responses to apelin in comparison to control rats. It is worth noting that diabetes did not only alter the peptide potency in these experimental groups but also significantly increased the maximum responses when Kca and BKca blockers preincubated. In conclusion, our findings shed light on the mechanisms behind diabetes-induced aortic artery hypo-reactivity to apelin which involve the inhibition of endothelial NO synthase activities and decreased contribution of Kca, BKca, IKca, Kv, Kir and KATP channels.

The roles of NADPH oxidase and PKC pathways in the modulation of GLP-1 induced-vasorelaxation in diabetic rat aorta

A hormone of the incretin system known as glucagon-like peptide-1 (GLP-1) is important for a number of glucoregulatory functions. This study aimed to investigate the effect of inhibitors on the vasorelaxant response of GLP-1 in T1D rats. A single subcutaneous injection of 50 mg/kg of streptozotocin (STZ) was used to develop diabetes mellitus. Eighty aortic rings from twenty male albino rats were prepared. An Automatic Organ Bath was used. In our study, apocynin increased vascular response to GLP- 1 in the non-diabetic group with (Emax:72.40±0.350) and (pD2: -9.923±0.444). In induced diabetes, the NADPH oxidase inhibitor decreased GLP-1 vasodilatation property with (Emax; 68.91±2.002) and (pD2: -9.480±0.138). The results show that bisindolylmaleimide IX (RO31-8220) has an increased effect on GLP-1 vasodilation in non-diabetic groups with (Emax:88.45±38.18) and (pD2: -10.81±0.281). While in induced diabetic rat’s vascular relaxation of GLP-1 decreased with (Emax: 77.73±2.801) and (pD2: - 10.28±0.203). The data analysis demonstrated that rotenone with (Emax: 63.69±35.10) (pD2: - 9.612±0.246), and in diabetic rats with (Emax:69.98±22.94) and (pD2: -9.612±0.246). In our study oxypurinol with (Emax: 82.16±16.10) and (pD2: - 9.434±0.443), and in diabetic rats with (Emax: 58.03±8.350) and (pD2: -9.612±0.246). We concluded that inhibitors could increase the vasorelaxant response of GLP-1 in non-diabetic rats, while this vasorelaxant response of GLP-1 diminished in diabetic-induced rats.

Effect of sunkist orange peel nanoparticle granules on cardiac and aorta histopathology in diabetic rats

Sunkist oranges (Citrus sinensis (L.) Osbeck) is rich in anthocyanins (95% of which are represented by cyanidin-3-glucoside and cyanidin-3-6"-malonyl-glucoside), flavanones (hesperidin and narirutin), hydroxycinnamic acid, carotenoids, sugars, minerals, and fiber, which offer health benefits. This study aimed to evaluate the efficacy of sunkist orange peel nanoparticle granules on the histopathological appearance of the cardiac and aorta in alloxan-induced diabetic rats. This study used a post-test experimental design, with a control group. Twenty-five male Wistar rats were randomly divided into five groups: negative control (alloxan+distilled water), positive control (alloxan+metformin), treatment 1 (alloxan+granular nanoparticles 50 mg/kg BW), treatment 2 (alloxan+granular nanoparticles 70 mg/kg BW), and treatment 3 (alloxan+granular nanoparticles 100 mg/kg BW). The heart and aorta were prepared for observation using 10x ocular magnification and 40x objective lens magnification. Kruskal-Wallis statistical test results revealed a significant difference in the average cardiac histopathological score between the treatment groups (p = 0.011). The amount of aortic endothelial cell damage can be seen from the presence of foam cells in the K(-) treatment group, while the K(+), P1, P2, and P3 groups did not have foam cells in the aortic endothelium. The findings of this study indicate that sunkist orange peel extract nanoparticles in granular form improve cardiac and aortic histopathology, with a dose of 100 mg/kg BB being the best dose for improving cardiac and aortic histopathology.

Adding SGLT2 Cotransporter Inhibitor to PPARγ Activator Does Not Provide an Additive Effect in the Management of Diabetes-Induced Vascular Dysfunction

Introduction: Endothelial dysfunction (ED) plays a key role in the pathogenesis of diabetic vascular complications. In monotherapy, dapagliflozin (Dapa) as well as pioglitazone (Pio) prevent the progression of target organ damage in both type 1 (T1DM) and type 2 diabetes. We investigated whether the simultaneous PPAR-γ activation and SGLT2 cotransporter inhibition significantly alleviate ED-related pathological processes and thus normalize vascular response in experimental T1DM. Methods: Experimental diabetes was induced by streptozotocin (STZ; 55 mg/kg, i.p.) in Wistar rats. Dapa (10 mg/kg), Pio (12 mg/kg), or their combination were administrated to the STZ rats orally. Six weeks after STZ administration, the aorta was excised for functional studies and real-time qPCR analysis. Results: In the aorta of diabetic rats, impaired endothelium-dependent and independent relaxation were accompanied by the imbalance between vasoactive factors (eNos, Et1) and overexpression of inflammation (Tnfα, Il1b, Il6, Icam, Vcam) and oxidative stress (Cybb) markers. Pio monotherapy normalized response to vasoactive substances and restored balance between Et1-eNos expression, while Dapa treatment was ineffective. Nevertheless, Dapa and Pio monotherapy significantly reverted inflammation and oxidative stress markers to normal values. The combination treatment exhibited an additive effect in modulating Il6 expression, reaching the effect of Pio monotherapy in other measured parameters. Conclusion: Particularly, Pio exerts a vasoprotective character when used in monotherapy. When combined with Dapa, it does not exhibit an expected additive effect within modulating vasoreactivity or oxidative stress, though having a significant influence on IL6 downregulation.

The Beneficial Effect of Swimming Training Associated with Quercetin Administration on the Endothelial Nitric Oxide-Dependent Relaxation in the Aorta of Rats with Experimentally Induced Type 1 Diabetes Mellitus.

Type 1 diabetes mellitus is related to the vascular oxidative and nitrosative stress, the trigger for atherosclerosis and cardiovascular complications. The effects of moderate swimming training associated with quercetin oral administration were evaluated in aorta of rats with experimentally induced type 1 diabetes mellitus (T1DM), by analysing the nitric oxide-endothelial dependent relaxation (NO-EDR). T1DM rats received daily quercetin 30 mg/kg and followed the protocol of 5-weeks swimming exercise (30 min/day; 5 days/week). Aorta relaxation to acetylcholine (Ach) and sodium nitroprusside (SNP) were measured at the end of the experiment. Ach-induced endothelial dependent relaxation was significantly decreased in phenylephrine (PE) pre-contracted aorta of diabetic rats. Swimming exercise with quercetin administration preserved Ach-induced EDR but did not have any impact on SNP-induced endothelium-independent relaxation in the diabetic aorta. These findings suggest that quercetin administration associated with moderate swimming exercise could improve the endothelial NO-dependent relaxation in the aorta of rats with experimentally induced type 1 diabetes mellitus, showing that this therapeutical combination may improve and even prevent the vascular complications that occur in diabetic patients.

Bach1 modulates AKT3 transcription to participate in hyperglycaemia-mediated EndMT in vascular endothelial cells.

Hyperglycaemia-mediated endothelial-to-mesenchymal transition (EndMT) is involved in the occurrence and progression of cardiovascular complications in diabetic patients. Previous studies reported that AKT serine/threonine kinase 3 (AKT3) and Bric-a-brac/Tramtrack/Broad (BTB) and cap'n'collar (CNC) homology 1 (bach1) participates in endothelial injury and epithelial-to-mesenchymal transition. In the present study, we proposed that bach1 regulates AKT3 transcription, thus involved in hyperglycaemia-mediated EndMT in vascular endothelium. Our results indicated that hyperglycaemia/high glucose increased AKT3 expression and induced EndMT in aorta of diabetic rats and hyperglycaemic human umbilical vein endothelial cells (HUVECs). Moreover, inhibition of AKT3 expression reversed high glucose-mediated EndMT in HUVECs. Further, hyperglycaemia/high glucose augmented bach1 expression in aorta of diabetic rats and hyperglycaemic HUVECs. Furthermore, si-bach1 countered high glucose-induced AKT3 expression and EndMT in HUVECs. In addition, the effect of bach1 overexpression is similar to that of high glucose treatment, which was reversed by si-AKT3. ChIP assays found bach1 enriched in the promoter region of AKT3. Bach1 overexpression augmented AKT3 promoter activity, which lost after specific binding site mutation. Bach1 was involved in hyperglycaemia-induced EndMT via modulation of AKT3 transcription.

Effect of Topiroxostat on Reducing Oxidative Stress in the Aorta of Streptozotocin-Induced Diabetic Rats.

Xanthine oxidoreductase exists both intracellularly and extracellularly and induces vascular injury by producing reactive oxygen species (ROS). Here, we investigated the effects and mechanism of action of topiroxostat, a xanthine oxidase inhibitor, on ROS using an animal model of type 1 diabetes with persistent hyperglycemia. Six-week-old male Sprague-Dawley rats were administered 50 mg/kg streptozotocin to induce diabetes; at 8 weeks of age, animals were administered topiroxostat (0.3, 1, or 3 mg/kg) for 2 weeks through mixed feeding after which the aorta was sampled. The production of superoxide, a type of ROS, was measured by chemiluminescence and dihydroethidium staining. Cytotoxicity was evaluated by nitrotyrosine staining. Topiroxostat at 3 mg/kg significantly decreased blood urea nitrogen, e-selectin, urinary malondialdehyde, and the urinary albumin/creatinine ratio compared with the streptozotocin group. Superoxide production by xanthine oxidase anchored to the cell membrane was significantly decreased by topiroxostat at both 1 mg/kg and 3 mg/kg compared with the streptozotocin group. Dihydroethidium staining revealed no significant effect of topiroxostat administration on superoxide production. The fluorescence intensity of nitrotyrosine staining was significantly suppressed by 3 mg/kg topiroxostat. Topiroxostat was found to inhibit the production of ROS in the thoracic aorta and suppress vascular endothelial damage. The antioxidant effect of topiroxostat appears to be exerted via the inhibition of anchored xanthine oxidase.

PS-B07-9: THE EFFECT OF ROUTINE PHYSICAL ACTIVITY TOWARD THE AORTIC WALL AREA IN RAT MODEL OF TYPE 2 DIABETES MELLITUS

Background: The damages in pancreatic b-cell as one of the main pathophysiologies of type 2 diabetes mellitus (T2DM) may result in hypoinsulinemia and hyperglycemia. Physical activity plays an important role in the comprehensive management of diabetes mellitus. This study aimed to understand the effect of routine physical activity on the aortic wall area of T2DM rat model. Methods: This study is an animal model experimental research with a post-test only control group to measure the wall area of the abdominal aorta in diabetic rats after routine physical activity. Induction of T2DM in male Sprague Dawley rat was done by injecting streptozotocin 35 mg/kg intraperitoneally. The diabetic rats were divided into two groups: the first group get physical activity and the second group was not. The control was represented by a group that receive citrate buffer injection. A routine physical activity in low to moderate intensity is given using a special rat treadmill five times a week for nine weeks with a gradual rising of speed at 5–20m/minute for a maximum of 60 minutes. The rat abdominal aorta was stained by hematoxylin-eosin and the wall area was measured by ImageJ. Results: The mean of the wall area in diabetic rats with exercise is 452436.60(+42375.92) um2, in diabetic rats without exercise is 35998.81(+34724.68) um2, and in the control group is 434595.83(+34724.68) um2. The statistical analysis using the Kruskal-Wallis test shows no significant difference between the three groups (p = 0.052). Conclusion: In conclusion, diabetic rats with routine physical activity have a wider abdominal aorta wall area, but it is not statistically significant.

Citri Reticulatae Pericarpium (Chenpi) Protects against Endothelial Dysfunction and Vascular Inflammation in Diabetic Rats.

Dried tangerine peel (Citri reticulatae Pericarpium, CRP; Chenpi in Chinese) possesses medicine and food homology with hypolipidemic, anti-inflammatory and antioxidant activities. This study aimed to explore the protective effect of CRP extract on endothelial function and inflammation in type 2 diabetic rats and the related mechanisms. Type 2 diabetes mellitus was induced by high-fat diet (HFD)/streptozotocin (STZ) in male Sprague Dawley rats, and CRP extract was orally administered at 400 mg/kg/day for 4 weeks. Rat and mouse aortas were treated with high glucose and CRP extract ex vivo. The data showed that the ethanolic extract of CRP normalized blood pressure and the plasma lipid profile as well as the plasma levels of liver enzymes in diabetic rats. Impaired endothelium-dependent relaxations in aortas, carotid arteries and renal arteries were improved. CRP extract suppressed vascular inflammatory markers and induced AMPK activation in aortas of diabetic rats. Exposure to high glucose impaired vasodilation in aortas of rats and mice, and this impairment was prevented by co-incubation with CRP extract. In conclusion, our findings suggest that CRP extract protects endothelial function by inhibiting the vascular inflammatory state on activation of AMPK in diabetic rats.

Hexokinase Activator Attenuates Type 2 Diabetes Mellitus and Associated Endothelial Dysfunction in HFF-STZ-Induced Diabetic Rat

Hexokinase is an enzyme involved in the glucose metabolism pathway. Magnesium is an inherent cofactor of the Hexokinase enzyme. The plethora of literature suggested that hexokinase level was decreased in diabetic rats. Sodium metavanadate shows insulin-mimetic action. We designed this work to determine the effect of magnesium on diabetes and associated vascular complications in rats. Type-2 diabetes was induced by a high-fat diet and a low dose of streptozotocin.. Diabetic rats were divided into groups, i.e. normal, diabetic, magnesium sulfate, sodium metavanadate, a combination of glibenclamide and metformin, a variety of sodium metavanadate with glibenclamide and metformin, and a combination of magnesium sulfate with glibenclamide and metformin. Magnesium sulfate was used as a hexokinase activator. Blood glucose levels were measured before initiation, between, and after 4 weeks of treatment. Biochemical and tissue parameters were estimated for additional confirmation. A vascular study took the contractile response of hydrogen peroxide in rat thoracic aortas of different groups. Statistical comparisons between groups were performed by two-tailed one-way ANOVA followed by the Dunnett test. P-values <0.05 were considered statistically significant. Treatment with magnesium sulfate and sodium metavanadate (S.M.V.) alone and in combination significantly (p<0.05) modified the elevated blood glucose and various altered biochemical parameters in diabetic rats. Treatment showed a significant decrease (p < 0.001) n elevated contractile responses of hydrogen peroxide in thoracic aortas of diabetic rats Vs Normal Control). Hexokinase activation by magnesium and sodium metavanadate significantly reduced (** p < 0.01) diabetes as well as vascular complications.

Effects of sub-chronic, in vivo administration of sigma-1 receptor ligands on platelet and aortic arachidonate cascade in streptozotocin-induced diabetic rats.

Diabetes mellitus is a chronic metabolic disorder which induces endothelial dysfunction and platelet activation. Eicosanoids produced from arachidonic acid regulate cellular and vascular functions. Sigma-1 receptors (S1R) are expressed in platelets and endothelial cells and S1R expression is protective in diabetes. Our aim was to examine the influence of sub-chronic, in vivo administered S1R ligands PRE-084, (S)-L1 (a new compound) and NE-100 on the ex vivo arachidonic acid metabolism of platelets and aorta in streptozotocin-induced diabetic rats. The serum level of the S1R ligands was detected by LC-MS/MS before the ex vivo analysis. Sigma-1 receptor and cyclooxygenase gene expression in platelets were determined by RT-qPCR. The eicosanoid synthesis was examined with a radiolabelled arachidonic acid substrate and ELISA. One month after the onset of STZ-induced diabetes, in vehicle-treated, diabetic rat platelet TxB2 and aortic 6-k-PGF1α production dropped. Sub-chronic in vivo treatment of STZ-induced diabetes in rats for one week with PRE-084 enhanced vasoconstrictor and platelet aggregator and reduced vasodilator and anti-aggregator cyclooxygenase product formation. (S)-L1 reduced the synthesis of vasodilator and anti-aggregator cyclooxygenase metabolites and promoted the recovery of physiological platelet function in diabetic rats. The S1R antagonist NE-100 produced no significant changes in platelet arachidonic acid metabolism. (S)-L1 decreased the synthesis of vasoconstrictor and platelet aggregator cyclooxygenase metabolites, whereas NE-100 increased the quantity of aortic vasodilator and anti-aggregator cyclooxygenase products and promoted the recovery of diabetic endothelial dysfunction in the aorta. The novel S1R ligand, (S)-L1 had similar effects on eicosanoid synthesis in platelets as the agonist PRE-084 and in aortas as the antagonist NE-100. S1R ligands regulate cellular functions and local blood circulation by influencing arachidonic acid metabolism. In diabetes mellitus, the cell-specific effects of S1R ligands have a compensatory role and aid in restoring physiological balance between the platelet and vessel.

Inhibition of Endoplasmic Reticulum Stress Improves Acetylcholine-Mediated Relaxation in the Aorta of Type-2 Diabetic Rats.

Endoplasmic reticulum (ER) stress contributes to insulin resistance and macro- and microvascular complications associated with diabetes. This study aimed to evaluate the effect of ER stress inhibition on endothelial function in the aorta of type-2 diabetic rats. Type-2 diabetes was developed in male Sprague–Dawley rats using a high-fat diet and low-dose streptozotocin. Rat aortic tissues were harvested to study endothelial-dependent relaxation. The mechanisms for acetylcholine-mediated relaxation were investigated using pharmacological blockers, Western blotting, oxidative stress, and inflammatory markers. Acetylcholine-mediated relaxation was diminished in the aorta of diabetic rats compared to control rats; supplementation with TUDCA improved relaxation. In the aortas of control and diabetic rats receiving TUDCA, the relaxation was mediated via eNOS/PI3K/Akt, NAD(P)H, and the KATP channel. In diabetic rats, acetylcholine-mediated relaxation involved eNOS/PI3K/Akt and NAD(P)H, but not the KATP channel. The expression of ER stress markers was upregulated in the aorta of diabetic rats and reduced with TUDCA supplementation. The expression of eNOS and Akt were lower in diabetic rats but were upregulated after supplementation with TUDCA. The levels of MDA, IL-6, and SOD activity were higher in the aorta of the diabetic rats compared to control rats. This study demonstrated that endothelial function was impaired in diabetes, however, supplementation with TUDCA improved the function via eNOS/Akt/PI3K, NAD(P)H, and the KATP channel. The improvement of endothelial function was associated with increased expressions of eNOS and Akt. Thus, ER stress plays a crucial role in the impairment of endothelial-dependent relaxation. Mitigating ER stress could be a potential strategy for improving endothelial dysfunction in type-2 diabetes.

Diosgenin inhibits ER stress-induced inflammation in aorta via iRhom2/TACE mediated signaling in experimental diabetic rats: An in vivo and in silico approach

Hyperglycemia, hyperlipidemia, and atherosclerotic lesions may cause inflammation, which leads to chemokine production and changes in vascular responses. Hyperglycemia can impair normal protein folding by producing reactive oxygen species (ROS) and interacting with various signaling molecules, resulting in the activation of ER stress responses, that stimulates NF-kB, which regulates the expression of numerous genes involved in inflammation and vascular remodeling. Our previous studies have shown that diosgenin has a protective effect against streptozotocin (STZ) - induced oxidative damage in rat aorta. However, the therapeutic role of diosgenin on iRhom2/TACE signaling which has primarily been linked to the endoplasmic reticulum (ER)-stress induced inflammation is unknown. Diosgenin was administered (40 mg/kg b. wt, orally, for 4 weeks) to STZ-induced male albino rats. Fasting plasma glucose, blood pressure, nitrite level, lipid profile, and lipoprotein were assessed. Serum insulin and pro-inflammatory markers were analyzed using ELISA, mRNA and protein expression of iRhom2/TACE signaling molecules were analyzed using RT-PCR and western blotting analysis respectively. In silico study was also performed to find out the possible binding affinity of diosgenin with the ER stress signaling molecules. Through regulation of the iRhom2/TACE signaling molecules, diosgenin lowered dyslipidemia, hypertension, and pro-inflammatory cytokines (TNF-α, IL-1, IL-6, and IL-4) in the aorta of STZ induced diabetic rats. Results of molecular docking analysis also confirmed the potential binding interaction with iRhom2/TACE and TNF- α. These in silico and in vivo results indicated that a change in lipid profile and hypertension led to diabetes-related inflammation by promoting ER stress and, as a result, accelerating the aorta by generating proinflammatory cytokines and lipid deposition. This study concludes that diosgenin attenuates ER stress-induced inflammation in diabetic rat aorta by modulating the expression of pro-inflammatory, iRhom2/TACE mediated mechanism and hence diosgenin can be a therapeutic drug for the treatment of diabetes-induced inflammation.

ETS proto-oncogene 1 modulates PTP1B expression to participate in high glucose-mediated endothelial inflammation.

Hyperglycemia-induced endothelial inflammation participates in the pathogenesis of cardiovascular complications in diabetics. Previous studies showed that protein tyrosine phosphatase 1B (PTP1B) and ETS proto-oncogene 1 (ets1) are involved in hyperglycemia-induced endothelial inflammation. In this study, we hypothesized that ets1 modulates PTP1B expression, thus playing a crucial role in hyperglycemia-induced vascular endothelial inflammation. Our results indicated that high glucose increases monocyte/endothelial adhesion, vascular cell adhesion molecule-1 (VCAM-1) expression and p65 phosphorylation in human umbilical vein endothelial cells (HUVECs). Moreover, high glucose-mediated endothelial inflammation is reversed by PTP1B silencing. In addition, high glucose increases ets1 expression in HUVECs. silencing reverses high glucose-mediated endothelial inflammation. Furthermore, the effect of ets1 overexpression is similar to that of high glucose treatment, which is counteracted by si-PTP1B. The results from ChIP assays indicated that ets1 occupies the PTP1B promoter region. Ets1 overexpression enhances PTP1B promoter activity, which is disappeared after specific binding site mutation. experiments demonstrated that the expressions of VCAM-1, PTP1B, and ets1, as well as the phosphorylation of p65 are augmented in the aorta of diabetic rats. In conclusion, ets1 contributes to hyperglycemia-mediated endothelial inflammation via upregulation of PTP1B expression.

Antioxidative Activity of Wakouba, a Salt Extracted from Elaeis guineensis Jacq in Streptozotocin-Induced Diabetic Rats

Background: Oxidative stress plays a major role in the chronic complications of diabetes, high blood pressure, cancer etc. free radicals such as superoxyde anions, hydrogen peroxides cause severe cell damage. The use of plants is increasingly recommended to treat diseases related to oxidative stress.
 Aims: This work aims to evaluate the antioxidant properties of Wakouba, a salt extracted from Elaeis guineensis Jacq on biochemical markers of oxidative stress.
 Place and Duration of Study: Pharmacodynamie-biochemical UPR, Biology and Health Laboratory and Department of Radiology, Services Institute of Medical Sciences (SIMS), Services Hospital Lahore, between March 2017 and July 2018.
 Materials and Methods: Diabetes was induced in Wistar rats (Rattus norvegicus) by streptozotocin 55 mg / kg bw. The biochemical parameters such as insulin and glycemia, the activities and the level of markers of oxidative stress such as superoxide dismutase (SOD), Catalase (CAT) and Malondialdehyde (MDA) in the aorta, heart and the kidney were determined in the absence and presence of different doses of WAKOUBA (1000 and 2500 mg / kg bw) and GLIBENCLAMIDE, a reference product at 10 and 20 mg / kg bw.
 Results: The results showed that the administration of streptozotocin at 55 mg / kg bw in rats caused a significant drop (P<0.05) in insulin production followed by a significant increase (P < 0.05) in blood glucose. Similarly, during diabetes, the activities, and levels of oxidative stress markers (SOD, CAT and MDA) increased significantly (P < 0.05). WAKOUBA, at 1000 and 2500 mg / kg bw, significantly normalized insulin production, blood sugar levels, SOD and CAT activities and MDA levels in the aorta, heart, and kidneys in diabetic rats. The same results were obtained with GLIBENCLAMIDE at 10 and 20 mg / kg bw.
 Conclusion: This study showed that WAKOUBA, a salt extracted from Elaeis guineensis Jacq, lowered and normalized the activities of SOD, CAT and the level of MDA which are markers of oxidative stress in rats made diabetic by streptozocin. WAKOUBA also normalized insulin production and blood sugar levels in diabetic rats. WAKOUBA would have antioxidant properties coupled with antidiabetic properties, which might support its use in traditional medicine to treat diabetes.

Sitagliptin attenuates endothelial dysfunction independent of its blood glucose controlling effect

Although the contributions of sitagliptin to endothelial dysfunction in diabetes mellitus were previously reported, the mechanisms still undefined. Autophagy plays an important role in the development of diabetes mellitus, but its role in diabetic macrovascular complications is unclear. This study aims to observe the effect of sitagliptin on macrovascular endothelium in diabetes and explore the role of autophagy in this process. Diabetic rats were induced through administration of high-fat diet and intraperitoneal injection of streptozotocin. Then diabetic rats were treated with or without sitagliptin for 12 weeks. Endothelial damage and autophagy were measured. Human umbilical vein endothelial cells were cultured either in normal glucose or in high glucose medium and intervened with different concentrations of sitagliptin. Rapamycin was used to induce autophagy. Cell viability, apoptosis and autophagy were detected. The expressions of proteins in c-Jun N-terminal kinase (JNK)-Bcl-2-Beclin-1 pathway were measured. Sitagliptin attenuated injuries of endothelium in vivo and in vitro. The expression of microtubuleassociated protein 1 light chain 3 II (LC3II) and beclin-1 were increased in aortas of diabetic rats and cells cultured with high-glucose, while sitagliptin inhibited the over-expression of LC3II and beclin-1. In vitro pre-treatment with sitagliptin decreased rapamycin-induced autophagy. However, after pretreatment with rapamycin, the protective effect of sitagliptin on endothelial cells was abolished. Further studies revealed sitagliptin increased the expression of Bcl-2, while inhibited the expression of JNK in vivo. Sitagliptin attenuates injuries of vascular endothelial cells caused by high glucose through inhibiting over-activated autophagy. JNK-Bcl-2-Beclin-1 pathway may be involved in this process.

Sevoflurane and isoflurane inhibit KCl-induced, Rho kinase-mediated, and PI3K-participated vasoconstriction in aged diabetic rat aortas

BackgroundThe mechanism of volatile anesthetics on vascular smooth muscle (VSM) contraction in the setting of diabetes mellitus (DM) remains unclear. The current study was designed to determine the effects of sevoflurane (SEVO) and isoflurane (ISO) on phosphoinositide 3-kinase (PI3K) and Rho kinase (ROCK) mediated KCl-induced vasoconstriction in aged type 2 diabetic rats.MethodsKCl-induced (60 mM) contractions were examined in endothelium-denuded aortic rings from aged T2DM Otsuka Long-Evans Tokushima Fatty (OLETF) rats (65–70 weeks old), control age-matched nondiabetic Long-Evans Tokushima Otsuka (LETO) rats and young Wistar rats (6–8 weeks old). The effects of SEVO or ISO (1–3 minimum alveolar concentration, MAC) on KCl-induced vasoconstriction, as well as those of LY294002 (PI3K inhibitor) and Y27632 (ROCK inhibitor) were measured in aortic rings from the three groups using an isometric force transducer.ResultsKCl induced rapid and continuous contraction of aortic smooth muscle in the three groups, and the contraction was more obvious in OLETF rats.SEVO and ISO inhibited KCl-induced vasoconstriction in a concentration-dependent manner and were suppressed by LY294002 (10 µM) and Y27632 (1 µM). SEVO had a stronger inhibitory effect on the aortas of young Wistar rats than ISO, especially at 2 MAC and 3 MAC (P < 0.05). In aged rats, the inhibitory effect of ISO was stronger than that of SEVO, especially OLETF rats. There was no significant difference in the effects of different concentrations of ISO on arterial contraction among the three groups (P > 0.05). The effects of 1 MAC SEVO on Wistar rats and 3 MAC SEVO on OLETF rats, however, were noticeably and significantly different (P < 0.05).Compared with the control condition, LY294002 and Y27632 had the most noticeable effect on the KCl-induced contraction of aortic rings in OLETF rats (P < 0.01).ConclusionSEVO (3 MAC), ISO (1, 2, 3 MAC), LY294002 and Y27632 have more significant inhibitory effect on the contraction of vascular smooth muscle in aged T2MD rats. The mechanism of SEVO and ISO in vascular tension in T2DM is partly due to changes in PI3K and/or Rho kinase activity.

Potentiation of Acetylcholine-Induced Relaxation of Aorta in Male UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) Rats: Sex-Specific Responses.

Previous reports suggest that diabetes may differentially affect the vascular beds of females and males. The objectives of this study were to examine whether there were (1) sex differences in aortic function and (2) alterations in the relative contribution of endothelium-derived relaxing factors in modulating aortic reactivity in UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) rats. Endothelium-dependent vasorelaxation (EDV) in response to acetylcholine (ACh) was measured in aortic rings before and after exposure to pharmacological inhibitors. Relaxation responses to sodium nitroprusside were assessed in endothelium-denuded rings. Moreover, contractile responses to phenylephrine (PE) were measured before and after incubation of aortic rings with a nitric oxide synthase (NOS) inhibitor in the presence of indomethacin. Metabolic parameters and expression of molecules associated with vascular and insulin signaling as well as reactive oxygen species generation were determined. Diabetes slightly but significantly impaired EDV in response to ACh in aortas from females but potentiated the relaxation response in males. The potentiation of EDV in diabetic male aortas was accompanied by a traces of nitric oxide (NO)- and prostanoid-independent relaxation and elevated aortic expression of small- and intermediate conductance Ca2+-activated K+ channels in this group. The smooth muscle sensitivity to NO was not altered, whereas the responsiveness to PE was significantly enhanced in aortas of diabetic groups in both sexes. Endothelium-derived NO during smooth muscle contraction, as assessed by the potentiation of the response to PE after NOS inhibition, was reduced in aortas of diabetic rats regardless of sex. Accordingly, decreases in pAkt and peNOS were observed in aortas from diabetic rats in both sexes compared with controls. Our data suggest that a decrease in insulin sensitivity via pAkt-peNOS-dependent signaling and an increase in oxidative stress may contribute to the elevated contractile responses observed in diabetic aortas in both sexes. This study demonstrates that aortic function in UCD-T2DM rats is altered in both sexes. Here, we provide the first evidence of sexual dimorphism in aortic relaxation in UCD-T2DM rats.

Histomorphological and Immunohistochemical Study on the Possible Effect of Vitamin E on Aortic Wall Remodeling in Streptozotocin (STZ)-Induced Diabetic Rats

background: The number of diabetics around the world will reach three hundred million by 2025. Vascular dysfunction is a common finding of both diabetes and glucose intolerance. The repercussions of hyperglycemia on the endothelium and smooth muscle cells contribute to the high risk of cardiovascular disease in type 1 and type 2 diabetes as well. Aim of the work: The purpose of this study was to investigate the possible immunomodulatory effect of vitamin E on the remodeling of aortic wall in STZ-induced diabetic rats histologically, immunohistochemically, and morphometrically.Materials & Methods: Thirty adult male albino rats were equally divided into 3 groups: control, five rats received a single intraperitoneal injection of 0.1 ml.0.1 M citrate buffer (pH 4.4), and 5 rats administered 2 ml of corn oil by oral gavage.; diabetes group (injected intraperitoneally with 65 mg/kg of streptozotocin in 0.1 ml citrate buffer), and diabetic+ vitamin E groups given Vitamin E (300 mg/kg) for 10 weeks after induction of diabetes. Sections of aortic specimens were stained with HE it significantly decreased tunica media thickness, collagen, and smooth muscle cells; vitamin E also improved elastin destruction and enhanced the expression of eNOS in the endothelial cells and suppressed α-SMA immunoreactivity in the wall of the aorta in diabetic rats. Conclusion: Vitamin ameliorated the histological remodeling of the aortic wall in diabetic rats that was confirmed histologically and immunohistochemically through the regulation of e NOS and α -SMA expression.