Mechanisms underlying quercetin-induced vasorelaxation in aorta of subchronic diabetic rats: an in vitro study

In this study, the mechanisms involved in vasorelaxant effect of the flavonoid quercetin was investigated in isolated aortic rings from streptozotocin (STZ)-diabetic rats. After 4 weeks, addition of quercetin (0.1 muM-1 mM) caused a significant dose-dependent relaxation of noradrenaline (NA)- and KCl-preconstricted rings in both control and diabetic groups with a significant inter-group difference of P<0.01. Furthermore, both nitro-L-arginine-methyl ester (L-NAME, 100 muM) and indomethacin (10 muM) markedly attenuated the vasorelaxant responses following quercetin application. Meanwhile, endothelium removal significantly attenuated the quercetin-induced vasorelaxation. It is concluded that the quercetin can relax the preconstricted rings of aorta in subchronic STZ-diabetic rats through nitric oxide- and prostaglandin-mediated pathways, which themselves could be considered as endothelium-dependent. (C) 2004 Elsevier Inc. All rights reserved

Endothelium-dependent attenuating effect of Trigonella foenum-graecum on the contractile vascular reactivity of diabetic rats

The present study was undertaken to determine whether two-month treatment of streptozotocin (STZ)-diabetic rats with aqueous leaf extract of Trigonella foenum-graecum (TFG; 200 mg/kg; i.p.) could improve thoracic aortic responsiveness and to evaluate its endothelium dependency. For this purpose, vascular responses to KCl and noradrenaline (NA) were measured. Diabetic state significantly increased contractile responses to KCl and NA in aortic rings in both endothelium-intact and -denuded rings. Extract-treated diabetic rats showed a significant lower maximal contractile response to KCl only in endothelium-intact rings as compared to diabetic rings. It is concluded that intraperitoneal administration of aqueous leaf extract of TFG for two months could improve some functional indices of the vascular system in diabetic state and the integrity of the endothelium is essential for its beneficial effects

The vasorelaxant effect of simvastatin in isolated aorta from diabetic rats

BACKGROUND: The increasing incidence of diabetes mellitus (DM) is of great clinical significance. In this study, we aimed to investigate whether exposure of endothelium-intact aortic rings to simvastatin could have a vasorelaxant effect in diabetic rats. METHODS: For induction of diabetes, streptozotocin (STZ) (60&thinsp;mg/kg, i.p., single dose) was used. After 1 month, the cumulative reaction of isolated endothelium-intact aortic rings was determined to KCl and phenylephrine (PE) in the absence and presence of nitric oxide (NO) synthase inhibitor, i.e., nitro-L-arginine-methyl ester (L-NAME), and prostaglandin synthesis inhibitor, i.e., indomethacin. Meanwhile, the role of extracellular calcium was assessed in this respect. RESULTS: At the end of the study, the addition of simvastatin (at a concentration &ge; 10&minus;5 M) caused a significant concentration-dependent relaxation response of PE-precontracted aortic rings for both control and diabetic groups (at a significant difference of P &lt; 0.050), and this difference did not exist for KCl-precontracted aortic rings. Furthermore, both L-NAME (100 &micro;M) and indomethacin (10 &micro;M) significantly diminished the vasorelaxant response following simvastatin addition. Meanwhile, there was no statistically significant difference between control and diabetic groups in the absence of extracellular calcium. CONCLUSION: The results of this study suggest that simvastatin is able to relax PE-precontracted aortic rings isolated from STZ-diabetic rats via modulation of NO- and prostaglandin-dependent signaling and its effect is not via modulation of calcium mobilization from intracellular stores

The effect of chronic silymarin on serum level of some enzyme markers and tissue level of malondialdehyde in diabetic rats

Background and Aim: Diabetes mellitus causes enhanced oxidative stress due to increased production of oxygen free radicals and decreased activity of antioxidant defense system. Flavonolignan Silymarin has an antidiabetic effect. This study was conducted to evaluate the effect of its chronic administration on serum levels of aspartate and alanine aminotranferase and the heart and liver level of malondialdehyde. Materials and Methods: In this experimental study, 40 male Wistar rats were divided into 5 equal groups, i.e. control, Silymarin -treated control (100 mg/kg), diabetic, and two Silymarin- treated diabetic groups (50 and 100 mg/kg). Silymarin was daily administered (i.p.) to each of the group members ten days after streptozotocin injection for 4 weeks. Serum levels of aspartate and alanine aminotranferase were measured both before and at the end of the study. In addition, level of malondialdehyde (MDA) was measured in the liver and the heart tissues on the basis of the reaction of thiobarbituric acid. Results: Serum glucose level in high dose Silymarin-treated diabetic group was significantly lower as compared to diabetics in the sixth week (P=0.007).Moreover, diabetic rats showed a significant increase in their aspartate serum level (P=0.028) and alanine aminotranferase (P=0.008) and Silymarin treatment only significantly reduced serum level of alanine aminotranferase (P=0.034). In addition, diabetes was followed by increased level of MDA in the liver (P=0.008) and the heart (P=0.009) tissues and high-dose Silymarin treatment significantly reduced MDA level only in the liver tissues (P=0.026). Conclusion: Long-term treatment with silymarin at a dose of 100 mg/kg can attenuate serum level of alanine aminotranferase and hepatic MDA level and does not have any significant effects on serum level of aspartate aminotranferase and cardiac tissue level of MDA in the administered dose

Soybean feeding improves vascular dysfunction and atte- nuates oxidative stress in streptozotocin-diabetic rats

A B S T R A C T Background and Objective: The effect of chronic dietary soybean (Glycine max L.) on aortic reactivity of streptozotocin (STZ)-diabetic rats was studied. Materials and Methods: Male diabetic rats received soybean for 7 weeks 1 week after diabetes induction at weight ratios of 3 and 6%. Contractile responses to KCl and phenylephrine (PE) and relaxation response to acetylcholine (ACh) were obtained from aortic rings. Results: Maximum contractile response of endothelium-intact rings to PE was significantly lower in soybean6%-treated diabetic rats relative to untreated diabetics (p&lt;0.05) and endothelium removal abolished this difference. Endothelium-dependent relaxation to ACh was significantly higher in soybean6%-treated diabetic rats as compared to diabetic ones (p&lt;0.05) and pretreatment of rings with nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME) and/or indomethacin attenuated it. Two-month diabetes also resulted in an elevation of malondialdehyde (MDA) and decreased superoxide dismutase (SOD) activity and soybean treatment significantly reversed the increased MDA content and reduced activity of SOD. Conclusion: Therefore, chronic treatment of diabetic rats with soybean could dose-dependently prevent some abnormal changes in vascular reactivity in diabetic rats through nitric oxide-and prostaglandin-related pathways and via attenuation of oxidative stress in aortic tissue and endothelium integrity seems essential for this effect

The effect of Marrubium vulgare on contractile reactivity of aorta in diabetic rats

BACKGROUND: The incidence of atherosclerosis and cardiovascular diseases increases in diabetes mellitus patients. Therefore, the effects of a two-month oral administration of Marrubium vulgare (MV) on contractile reactivity of isolated aorta in an experimental model of diabetic rats were evaluated in the present study. METHODS: Male Wistar rats (n = 44) were randomly divided into control, MV-treated control, diabetic, and MV-treated diabetic groups. For induction of diabetes, streptozotocin (STZ) was intraperitoneally administered (60 mg/kg). MV-treated groups received MV mixed with standard pelleted food at a weight ratio of 1/15. After 2 months, contractile reactivity of aortic rings to potassium chloride (KCl) and noradrenaline was determined using isolated tissue setup. RESULTS: Serum glucose levels showed significant increases in the diabetic group at 4th and 8th weeks (P &lt; 0.001), while this increase was not observed in MV-treated diabetic group at the 8th week. In addition, the latter group showed a lower contraction to KCl (P &lt; 0.05) and noradrenaline (P &lt; 0.05) as compared to the diabetic group. Meanwhile, there was no significant difference between the control and MV-treated control groups regarding contractile reactivity. CONCLUSION: It can be concluded that oral administration of MV for 2 months could attenuate the contractile responsiveness of the vascular system which may prevent the development of hypertension in diabetic rats. Keywords: Marrubium Vulgare, Vascular System, Diabetes Mellitus, Contractile Response, Rat &nbsp;</p

Percutaneous trans-ulnar artery approach for coronary angiography and angioplasty; A case series study

BACKGROUND: Coronary angiography is the gold standard method for diagnosis of coronary heart disease and usually performed by femoral approach that has several complications. To reduce these complications, upper extremity approach is increasingly used and is becoming preferred access site by many interventionists. Although radial approach is relatively well studied, safety, feasibility and risk of applying ulnar approach in not clearly known yet. METHODS: We followed 97 patients (man = 56%, mean &plusmn; standard deviation of age = 57 &plusmn; 18) who had undergone coronary angiography or angioplasty via ulnar approach for 6-10 months and recorded their outcomes. RESULTS: In 97 patients out of 105 ones (92.38%), procedure through ulnar access were successfully done. Unsuccessful puncture (3 patients), wiring (2 patients), passing of sheet (2 patients), and anatomically unsuitable ulnar artery (1 patient) were the reasons of failure. In 94 patients (89.52%), the angiography and angioplasty was done without any complications. Five patients (5.1%) hematoma and 11 patients (11%) experienced low-grade pain that resolved with painkiller. No infection, amputation or need for surgery was reported. CONCLUSION: This study demonstrated that ulnar access in our patients was a safe and practical approach for coronary angiography or angioplasty, without any major complication. Bearing in mind its high success rate, it can be utilized when a radial artery is not useful for the catheterization and in cases such as prior harvesting of the radial artery (in prior coronary artery bypass grafting).&nbsp;</p

Endothelium-dependent Effect of Sesame Seed Feeding on Vascular Reactivity of Streptozotocin-diabetic Rats: Underlying Mechanisms

Abstract Cardiovascular disorders continue to constitute major causes of morbidity and mortality in diabetic patients. In this study, the effect of chronic administration of sesame (Sesamum indicum L) seed feeding was studied on aortic reactivity of streptozotocin (STZ)-diabetic rats. Male diabetic rats received sesame seed-mixed food at weight ratios of 3% and 6% for 7 weeks, one week after diabetes induction. Contractile responses to KCl and phenylephrine (PE) and relaxation response to acetylcholine (ACh) and sodium nitroprusside (SNP) were obtained from aortic rings. Maximum contractile response of endothelium-intact rings to PE was significantly lower in sesame-treated diabetic rats (at a ratio of 6%) relative to untreated diabetics and endothelium removal abolished this difference. Endotheliumdependent relaxation to ACh was also significantly higher in sesame-treated diabetic rats (at a ratio of 6%) as compared to diabetic rats and pretreatment of rings with nitric oxide synthase inhibitor, N(G)-nitro-l-arginine methyl ester (L-NAME) significantly attenuated the observed response. Two-month diabetes also resulted in an elevation of malondialdehyde (MDA) and decreased superoxide dismutase (SOD) activity and sesame treatment significantly reversed the increased MDA content and restored activity of SOD. We thus conclude that chronic treatment of diabetic rats with sesame seed could in a dosemanner prevent some abnormal changes in vascular reactivity through nitric oxide and via attenuation of oxidative stress in aortic tissue and endothelium integrity is necessary for this beneficial effect. for the first time, the beneficial effect of chronic sesame seed feeding on the improvement of aortic reactivity of STZ-diabetic rats and to investigate some underlying mechanisms. Experimental Animals Male albino Wistar rats (n= 48) (Pasteur&apos;s institute, Tehran, IR Iran), weighing 235-300 g, were housed in an air-conditioned colony room at 21 ± 2 °C and supplied with standard pellet diet and tap water ad libitum. Procedures involving animals and their care were conducted in conformity with NIH guidelines for the care and use of laboratory animals. Experimental protocol The rats were rendered diabetic by a single intraperitoneal dose of 60 mg kg -1 STZ freshly dissolved in ice-cold 0.1 M citrate buffer (pH 4.5). Age-matched normal animals that received an injection of an equivalent volume of buffer comprised a non-diabetic control group. One week after STZ injection, overnight fasting blood samples were collected and serum glucose concentration was measured using glucose oxidation method (Zistchimie, Tehran). Only those animals with a serum glucose level higher than 250 mg/dL were considered as diabetic. During the subsequent weeks, diabetes was reconfirmed by the presence of polyphagia, polydipsia, polyuria, and weight loss. Normal and hyperglycemic rats (a total of 48) were randomly allocated and similarly grouped into six groups (eight in each): normal vehicletreated control, sesame-treated controls in two subgroups, diabetic, and sesame-treated diabetics in two subgroups. Sesame seed powder was mixed with standard food at weight ratios of 3% and 6% and food was freely available to rats throughout the experimental period for 7 weeks. Changes in body weight were regularly recorded during the study. The rats were finally anesthetized with diethyl ether, decapitated, and through opening the abdomen, descending thoracic aorta was carefully excised and placed in a petri dish filled with cold Krebs solutio

Perspective on the hospital incidence rate of deep venous coagulopathy: Clinical and biochemical diagnostic markers

Background: Identifying factors contributing to the increased risk of deep venous thrombosis (DVT) in each population is vital, because of its life-threatening outcome. The current study aims to find the diagnostic performance of some laboratory coagulation markers for predicting DVT in an Iranian population complaining of DVT in the lower limbs. Patients and Methods: For this study, 66 consecutive patients with documented DVT, admitted to the Al-Zahra Hospital in Isfahan for the first time, were considered as the case group and 33 patients without DVT documentations were included as the control group. DVT was considered when there was visualization of thrombus or non-compressibility of the vein, confirmed by bilateral lower extremity compression Doppler ultrasonographic examination. Homocysteine, antiphospholipid, and anticardiolipin antibodies were measured in both groups by using sensitive ELISA kits. Protein C was measured via a functional clotting method, and prothrombin was measured by a kinetic, enzymatic assay. Results: Multivariable analysis showed that the serum homocysteine levels was potentially associated with the presence of DVT after adjusting for age and gender (OR: 1.038, 95% CI: 1.007-1.070, P = 0.017). Comparison of the C statistic showed a partially good discrimination of homocysteine for DVT, with the area under the receiver operating characteristic (ROC) curve being 0.614 and with the optimal cut-off value of 16.5 micromol/L (μmol/L) for men and 14.5 μmol/L for women. Conclusion: Hyperhomocysteinemia could be considered as an independent risk factor for DVT, with an actual acceptable prognostic value, in the Iran population