Vitamin E suppresses aortic ultrastructural alterations induced by toxic doses of monosodium glutamate / La vitamina E suprime las alteraciones ultraestructurales aórticas inducidas por dosis tóxicas de glutamato monosódico

SUMMARY: An association between certain food additives and chronic diseases is reported. Current study determined whether administering toxic doses of the food additive monosodium glutamate (MSG) into rats can induce aortopathy in association with the oxidative stress and inflammatory biomarkers upregulation and whether the effects of MSG overdose can be inhibited by vitamin E. MSG at a dose of (4 mg/kg; orally) that exceeds the average human daily consumption by 1000x was administered daily for 7 days to the rats in the model group. Whereas, rats treated with vitamin E were divided into two groups and given daily doses of MSG plus 100 mg/ kg vitamin E or MSG plus 300 mg/kg vitamin E. On the eighth day, all rats were culled. Using light and electron microscopy examinations, a profound aortic injury in the model group was observed demonstrated by damaged endothelial layer, degenerated smooth muscle cells (SMC) with vacuoles and condensed nuclei, vacuolated cytoplasm, disrupted plasma membrane, interrupted internal elastic lamina, clumped chromatin, and damaged actin and myosin filaments. Vitamin E significantly protected aorta tissue and cells as well as inhibited MSG-induced tissue malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). The highest used vitamin E dosage was more effective. Additionally, a significant correlation was observed between the aortic injury degree and tissue MDA, TNF-α, IL-6, and superoxide dismutase (SOD) levels (p=0.001). Vitamin E effectively protects against aortopathy induced by toxic doses of MSG in rats and inhibits oxidative stress and inflammation.

RESUMEN: Se reporta una asociación entre ciertos aditivos alimentarios y enfermedades crónicas. El objetivo de este estudio fue determinar si la administración de dosis tóxicas del aditivo alimentario glutamato monosódico (MSG) en ratas puede inducir aortopatía en asociación con el estrés oxidativo y la regulación positiva de los biomarcadores inflamatorios y si el efecto de una sobredosis de MSG se puede inhibir con vitamina E. Se administró MSG diariamente durante 7 días una dosis de (4 g/kg; por vía oral) que excede el consumo diario humano promedio, en 1000x a las ratas del grupo modelo. Mientras que las ratas tratadas con vitamina E se dividieron en dos grupos y se administraron dosis diarias de MSG más 100 mg/kg de vitamina E o MSG más 300 mg/kg de vitamina E. Todas las ratas fueron sacrificadas en el octavo día. Usando exámenes de microscopía óptica y electrónica, se observó una lesión aórtica profunda en el grupo modelo demostrada por una capa endotelial dañada, células musculares lisas degeneradas (SMC) con vacuolas y núcleos condensados, citoplasma vacuolado, membrana plasmática rota, lámina elástica interna interrumpida, cromatina agrupada y filamentos de actina y miosina dañados. La vitamina E protegió significativamente el tejido y las células de la aorta, además de inhibir el malondialdehído tisular (MDA) inducido por MSG, la interleucina-6 (IL-6) y el factor de necrosis tumoral alfa (TNF-α). La dosis más alta de vitamina E utilizada fue más efectiva. Además, se observó una correlación significativa entre el grado de lesión aórtica y los niveles tisulares de MDA, TNF-α, IL-6 y superóxido dismutasa (SOD) (p=0,001). La vitamina E efectivamente protege contra la aortopatía inducida por dosis tóxicas de MSG en ratas e inhibe el estrés oxidativo y la inflamación.

Are statins a risk factor in patients with atherosclerosis? / ¿Son las estatinas un factor de riesgo en pacientes con aterosclerosis?

SUMMARY: Statins inhibit cholesterol synthesis, but also have other pleiotropic effects. There are indications that they affect macrophage survival trough the regulation of apoptosis. We analyzed 50 samples of aortic wall, selected based on statins in patients' therapy (n=25, Th-S group) or statin-free therapy (n=25, Th-nonS group). Each group had 5 samples of healthy aortic tissue, 10 samples of mild and 10 samples of severe atherosclerotic changes in aortic wall. Tissue was stained with hematoxylin-eosin and immunohistochemical methods (anti-Bcl-2 antibody). Presence of Bcl2-positive macrophages (Bcl-2+ MP) was determined semiquantitatively, and data were processed in Microsoft Excell and IMB SPSS 23 Statistics. 60 % of patients in the Th-S group had a mild increase of Bcl-2+ MP The use of statins leads to a significantly more frequent increase in Bcl2+ macrophages in the intima of the healthy aortic tissue. Analysis of all aortic samples with pathohistological diagnosis showed that statin therapy was statistically significantly more often leading to a markedly increased presence of Bcl-2+ MP. In the media, all samples of the Th-S group have a mild increase of Bcl-2+ MP, and in adventitia 40 % of patients. The use of statins more often leads to a markedly increased presence of Bcl-2+ MP in aortic tissue with diagnosed mild and severe atherosclerosis. In samples of severe atherosclerosis, statins lead to a markedly increased presence of Bcl-2+ MP in the parts of the plaque towards the intima and towards the media. Statins lead to an increased presence of Bcl-2+ macrophages, prolong their life, both in healthy and atherosclerotic altered aortic tissue. This indicates potentiation of inflammation and damage to the aortic wall, and calls into question the positive effect of statins on the aortic wall with atherosclerosis.

RESUMEN: Las estatinas inhiben la síntesis de colesterol, pero también tienen otros efectos pleiotrópicos. Hay indicios de que afectan la supervivencia de los macrófagos a través de la regulación de la apoptosis.Se analizaron 50 muestras de pared aórtica, seleccionadas en base a estatinas en tratamiento de pacientes (n=25, grupo Th-S) o en tratamiento libre de estatinas (n=25, grupo Th- nonS). Cada grupo tenía 5 muestras de tejido aórtico sano, 10 muestras de cambios ateroscleróticos leves y 10 muestras de cambios ateroscleróticos severos en la pared aórtica. El tejido se tiñó con hematoxilina-eosina y métodos inmunohistoquímicos (anticuerpo anti-Bcl-2). La presencia de macrófagos positivos para Bcl2 (Bcl- 2+ MP) se determinó semicuantitativamente y los datos se procesaron en Microsoft Excell e IMB SPSS 23 Statistics. El 60 % de los pacientes del grupo Th-S tuvo un aumento leve de Bcl-2+ MP. El uso de estatinas conduce a un aumento significativamente más frecuente de macrófagos Bcl2+ en la íntima del tejido aórtico sano. El análisis de todas las muestras aórticas con diagnóstico anatomopatológico mostró que la terapia con estatinas fue significativamente más frecuente desde el punto de vista estadístico, lo que condujo a una presencia marcadamente mayor de Bcl-2+ MP. En los medios, todas las muestras del grupo Th-S tienen un leve aumento de Bcl-2+ MP, y en adventicia en el 40 % de los pacientes. El uso de estatinas con mayor frecuencia conduce a una presencia marcadamente mayor de MP Bcl-2+ en el tejido aórtico con aterosclerosis leve y grave diagnosticada. En muestras de aterosclerosis severa, las estatinas conducen a una presencia aumentada de Bcl-2+ MP en las partes de la placa hacia la íntima y hacia la media. Las estatinas conducen a una mayor presencia de macrófagos Bcl-2+, prolongan su vida, tanto en tejido aórtico sano como aterosclerótico alterado. Esto indica la potenciación de la inflamación y el daño a la pared aórtica y pone en duda el efecto positivo de las estatinas en la pared aórtica con aterosclerosis.

IInvestigation of possible oxidative damage caused by formaldehyde exposure in the rat's heart and aorta tissue / Investigación de posible daño oxidativo causado por la exposición al formaldehído en el corazón de la rata y tejido de la aorta

SUMMARY: Formaldehyde (FA) is a toxic substance used frequently in the field of medicine as well as in many industrial areas. Especially people working in the field of anatomy, histology, and pathology are in high risk group because of the use of the FA. Studies showing the effects of FA on the cardiovascular system are few in number. The purpose of the present study was to investigate the effects of FA exposure, which we believe can cause oxidative stress, on the heart and aorta with various biochemical analyses. A total of 24 Wistar Albino rats were used in our study. We divided the rats into 3 groups as the Control Group (CG), the group exposed to low-dose FA (avg. 1 ppm) (DDG) Group, and the group exposed to high-dose FA (avg. 10 ppm) (YDG). At the end of the subchronic FA exposure, the blood samples, heart and aorta tissues of the rats were taken and subjected to biochemical analyses. As a result of the analyses, statistically significant differences were detected between CG (2.96?0.85 ng/mg), and HDG (2.08?0.77 ng/mg) in aortic tissues in TXNIP analysis (p<0.05). In heart tissues, significant differences were detected between CG (0.73?0.27 ng/mg) and LDG (1.13?0.22 ng/mg) (p<0.05). Statistically significant differences were also detected between CG (1.98?0.31 mM/ml) and YDG (2.43?0.31 mM/ml) in serum MDA analyses (p<0.05). It was shown that subchronic application of FA to LDG rats through inhalation had no effects on apoptosis markers in heart tissues. More studies are required to show FA toxicity and the mechanism of action of pathology on the cardiovascular system. We believe that our study will contribute to clarifying the roles of mild and subchronic exposure of FA in heart and aortic tissues in terms of oxidative stress risk.

RESUMEN: El formaldehído es una sustancia tóxica que se utiliza con frecuencia en el campo de la medicina, así como en muchas áreas industriales. Especialmente las personas que trabajan en el area de la anatomía, y patología se encuentran en el grupo de alto riesgo debido al uso de esta sustancia. Pocos son los estudios que muestran los efectos del formaldehído en el sistema cardiovascular. El propósito del presente estudio fue investigar a través de análisis bioquímicos, los efectos de la exposición a formaldehído, que podría causar estrés oxidativo, en el corazón y la aorta. Se utilizaron un total de 24 ratas Albinas Wistar. Dividimos a las ratas en 3 grupos: grupo control (GC), grupo expuesto a dosis bajas de AG (promedio 1 ppm) (DDG) y grupo expuesto a dosis altas de AG (promedio 10 ppm) (YDG). Al término de la exposición a FA subcrónica, se tomaron muestras de sangre, tejido cardíaco y aorta de las ratas y se sometieron a análisis bioquímicos. Como resultado de los análisis, se detec- taron diferencias estadísticamente significativas entre GC (2,96 ? 0,85 ng / mg) y HDG (2,08 ? 0,77 ng / mg) en los tejidos aórticos en el análisis TXNIP (p <0,05). En los tejidos cardíacos se detectaron diferencias significativas entre GC (0,73 ? 0,27 ng / mg) y LDG (1,13 ? 0,22 ng / mg) (p <0,05). También se detectaron diferencias estadísticamente significativas entre CG (1,98 ? 0,31 mM / ml) y YDG (2,43 ? 0,31 mM / ml) en los análisis de MDA en suero (p <0,05). Se demostró que la aplicación subcrónica de formaldehído a ratas LDG a través de la inhalación no tuvo efectos sobre los marcadores de apoptosis en los tejidos del corazón. Se requieren más estudios para demostrar la toxicidad de los AG y el mecanismo de acción de la patología en el sistema cardiovascular. Creemos que nuestro estudio contribuirá a aclarar las funciones de la exposición leve y subcrónica de formaldehído en los tejidos cardíacos y aórticos en términos de riesgo al estrés oxidativo.

Vanadium inhibits Type 2 diabetes mellitus-induced aortic ultrastructural alterations associated with the Inhibition of dyslipidemia and biomarkers of inflammation in rats / El vanadio inhibe las alteraciones ultraestructurales aórticas inducidas por la diabetes mellitus Tipo 2 asociadas con la inhibición de la dislipidemia y los biomarcadores de inflamación en ratas

The potential inhibitory effect of the insulin mimicking agent, vanadium on type 2 diabetes mellitus (T2DM)induced alterations to the aorta ultrastructure associated with the suppression of dyslipedima and biomarkers of inflammation has not been investigated before. Therefore, we tested whether vanadium can protect against aortic injury induced secondary to T2DM possibly via the inhibition of blood lipid and inflammatory biomarkers. T2DM was induced in rats by a high-fat diet and streptozotocin (50 mg/ kg), and the treatment group started vanadium treatment five days post diabetic induction and continued until being sacrificed at week 10. Using light and electron microscopy examinations, we observed in the model group substantial damage to the aorta tissue such as damaged endothelium, degenerative cellular changes with vacuolated cytoplasm and thickened internal elastic lamina that were substantially ameliorated by vanadium. Administration of vanadium to diabetic rats also significantly (p<0.05) reduced blood levels of glucose, hyperlipidemia and biomarkers of inflammation (TNF-a, IL-6). We conclude that vanadium protects against T2DM-induced aortic ultrastructural damage in rats, which is associated with the inhibition of blood sugar and lipid and inflammatory biomarkers.

El potencial efecto inhibidor del agente imitador de la insulina, el vanadio en las alteraciones inducidas por la diabetes mellitus tipo 2 (DM2) en la ultraestructura de la aorta, asociada con la supresión de dislipidemia y los biomarcadores de inflamación no se ha investigado anteriormente. El objetivo fue estudiar las propiedades del vanadio para proteger contra la lesión aórtica inducida a la DM2, a través de la inhibición de los lípidos sanguíneos y los biomarcadores inflamatorios. La DM2 fue inducida en ratas con una dieta alta en grasas y estreptozotocina (50 mg / kg), y el grupo de tratamiento fue sometido a un régimen continuo con vanadio, cinco días después de la inducción diabética hasta ser sacrificadas en la semana 10. Se utilizaron exámenes de luz y microscopía electrónica en el grupo modelo y se observó un daño sustancial al tejido de la aorta, como también en el endotelio; los cambios celulares degenerativos con citoplasma vacuolado y lámina elástica interna engrosada mejoró sustancialmente con vanadio. La administración de vanadio a ratas diabéticas también redujo significativamente (p <0,05) los niveles sanguíneos de la glucosa, hiperlipidemia y los biomarcadores de inflamación (TNFa, IL-6). En conclusión, el vanadio protege contra el daño ultraestructural aórtico inducido por T2DM en ratas, que es asociado con la inhibición del azúcar en la sangre y los biomarcadores de lípidos y de inflamatorios.

Possible mechanisms involved in the effect of the subchronic administration of rosuvastatin on endothelial function in rats with metabolic syndrome

Metabolic syndrome is a multifaceted condition associated with a greater risk of various disorders (e.g., diabetes and heart disease). In a rat model of metabolic syndrome, an acute in vitro application of rosuvastatin causes relaxation of aortic rings. Since the outcome of a subchronic rosuvastatin treatment is unknown, the present study explored its effect on acetylcholine-induced vasorelaxation of aortic rings from rats with metabolic syndrome. Animals were submitted to a 16-week treatment, including a standard diet, a cafeteria-style diet (CAF-diet), or a CAF-diet with daily rosuvastatin treatment (10 mg/kg). After confirming the development of metabolic syndrome in rats, aortic segments were extracted from these animals (those treated with rosuvastatin and untreated) and the acetylcholine-induced relaxant effect on the corresponding rings was evaluated. Concentration-response curves were constructed for this effect in the presence/absence of L-NAME, ODQ, KT 5823, 4-aminopyridine (4-AP), tetraethylammonium (TEA), apamin plus charybdotoxin, glibenclamide, indomethacin, clotrimazole, and cycloheximide pretreatment. Compared to rings from control rats, acetylcholine-induced vasorelaxation decreased in rings from animals with metabolic syndrome, and was maintained at a normal level in animals with metabolic syndrome plus rosuvastatin treatment. The effect of rosuvastatin was inhibited by L-NAME, ODQ, KT 5823, TEA, apamin plus charybdotoxin, but unaffected by 4-AP, glibenclamide, indomethacin, clotrimazole, or cycloheximide. In conclusion, the subchronic administration of rosuvastatin to rats with metabolic syndrome improved the acetylcholine-induced relaxant response, involving stimulation of the NO/cGMP/PKG/Ca2+-activated K+ channel pathway.

Evaluation of smooth muscle relaxant potential of Bismarckia nobilis (Hildebr. & Wendl.) in diarrhea, hypertension and asthma by ex-vivo and in-vivo method / Evaluación del potencial relajante en músculo liso de Bismarckia nobilis (Hildebr. & Wendl.) en diarrea, hipertensión y asma por métodos ex vivo e in vivo

To explore the mechanistic basis behind smooth muscle relaxant prospective of Bismarckia nobilis in gastrointestinal, respiratory and cardiovascular ailments. The methanolic extract of B. nobilis and sub-fractions have been evaluated in vitro rabbit isolated tissues, in vivo castor oil-induced diarrhea in rats and charcoal meal activity in mice. The B. nobilis extract relaxed spontaneous and K+(80 mM)- induced contractions in rabbit isolated jejunum preparations, CCh (1 µM) and K+ (80 mM)-induced contractions in tracheal and bladder preparations, PE (1 µM) and K+ (80 mM)-induced concentrations in aorta preparations, likewise verapamil. Spasmolytic activity of dichloromethane fraction is stronger as compared to aqueous fraction. In vivo castor oil-induced diarrhea in rats and charcoal meal activity in mice further supported spasmolytic activity. B. nobilis extract possess anti-spasmodic, anti-diarrheal, airway relaxant and vasodilator activities possible mediated through calcium channel blocking mechanism, justifying therapeutic utility of B. nobilis in diarrhea, asthma and hypertension.

El objetivo de trabajo fue explorar el mecanismo de acción relacionado con el efecto relajante del músculo liso inducido por Bismarckia nobilis (B. nobilis) en enfermedades gastrointestinales, respiratorias y cardiovasculares. El extracto metanólico de B. nobilis y subfracciones fue evaluado in vitro en tejidos aislados de conejos. Además se evaluó diarrea in vivo inducida con aceite de ricino en ratas y la actividad de harina de carbón vegetal en ratones. El extracto de B. nobilis relajó tanto las contracciones espontáneas como las inducidas por K+(80 mM) en preparaciones de yeyuno aisladas de conejos, las contracciones inducidas por PE (1 µM) y K+(80 mM) inducidas en preparaciones de aorta; de manera similar a verapamilo. La actividad espasmolítica de la fracción de diclorometano es más potente en comparación con la fracción acuosa. La diarrea inducida in vivo por el aceite de ricino en ratas y la actividad de la harina de carbón vegetal en ratones apoyaron aún más la actividad espasmolítica. El extracto de B. nobilis posee actividades antiespasmódicas, antidiarreicas, relajantes de las vías respiratorias y vasodilatadoras, posibles a través del mecanismo de bloqueo de los canales de calcio, lo que justifica la utilidad terapéutica de B. nobilis en la diarrea, el asma y la hipertensión.

Análise histomorfométrica da artéria aorta de ratas submetidas à administração repetida da associação de etinilestradiol e gestodeno / Histomorphometric analysis of the aorta of rats submitted to repeated administration of association of ethinylestradiol and gestodene

Introdução: Os anticoncepcionais orais vêm sofrendo alterações em suas concentrações de estrogênio e progestogênio, baseando-se no fato de que doses mais baixas estão associadas a menor incidência de alterações metabólicas e de efeitos adversos, como o comprometimento da morfologia e função da artéria aorta. O objetivo deste estudo é avaliar a influência dos anticoncepcionais nas propriedades morfofuncionais da artéria aorta, através do método histoquímico, demonstrando sua utilidade nas análises histopatológicas. Métodos: Para tanto, foram utilizadas 15 ratas divididas em 3 grupos; Grupo controle (GC), cujos animais não receberam tratamento hormonal; Grupo 2 (G2), onde os animais receberam tratamento diário de 15 µg de etinilestradiol + 60 µg de gestodeno; e Grupo 3 (G3), que recebeu 30 µg de etinilestradiol + 75 µg de gestodeno. Após o tratamento, os animais foram eutanasiados e as artérias retiradas para análise histológica. Resultados: Os valores encontrados com a técnica de coloração histológica de hematoxilina e eosina (HE), bem como na coloração específica em histoquímica com Alcian Blue, demonstram que no G3, tratados com uma dosagem superior de hormônio, 8% das ratas tem aumento relevante da espessura de suas artérias, ou seja, superior ao G2, que recebeu dosagem menor de hormônio, e GC, o qual não recebeu nenhum tipo de tratamento. Conclusão: Este estudo demonstra que existem relações entre o espessamento das artérias, de ratas submetidas a dosagens de etinilestradiol e gestodeno, com a grande quantidade de mucopolissacarídeos depositados entre as túnicas das artérias. (AU)

Introduction: Pharmacological development of hormonal contraceptives has been undergoing changes in estrogen and progesterone doses, based on the fact that lower doses are associated with a lower incidence of metabolic changes and adverse effects, such as impairment of morphology and function of the aortic artery. The aim of this study is to evaluate the influence of contraceptives on the morphofunctional properties of the aortic artery, using the histochemical method, demonstrating its usefulness in histopathological analyzes. Methods: For this purpose, 15 rats were divided into 3 groups; Control group (GC), whose animals did not receive hormonal treatment; Group 2 (G2), where the animals received a daily treatment of 15 µg of ethinylestradiol + 60 µg of gestodene; and Group 3 (G3), whose animals received 30 µg of ethinylestradiol + 75 µg of gestodene. After treatment, the animals were sacrificed and the arteries removed for histologic analysis. Results: The values found, with HE measurements and Alcian Blue histochemical staining, showed that in G3, treated with a higher hormone dosage, there are 8% of the rats with a relevant increase in the thickness of their arteries, that is, higher than that of G2, which received lower dosage of hormone and that of GC, which received no treatment. Conclusion: This study demonstrates that there are relations between the thickening of the arteries of rats submitted to dosages of ethinylestradiol and gestodene with the great amount of mucopolysaccharides deposited between the tunics of the arteries. (AU)

Effects of Continuous and Accumulated Exercise on Endothelial Function in Rat Aorta / Efeitos do Exercício Acumulado e Contínuo sobre a Função Endotelial em Aorta de Ratos

Abstract Background: The practice of exercise in short bouts repeated throughout the day may be an alternative strategy to lift people out of physical inactivity. Objective: to evaluate if accumulated exercise, as occurs in continuous exercise training, improve endothelial function in rat aorta. Methods: Wistar male rats were divided into three groups: continuous exercise (CEx, 1 hour on the treadmill) or accumulated exercise (AEx, 4 bouts of 15 minutes / day) for 5 days/week for 8 weeks, or sedentary (SED). During the training period, body weight gain and increase in exercise performance were recorded. On sacrifice day, aorta was dissected into rings (3-5 mm) and mounted on the organ bath. Results: Fitness was significantly greater in CEx and AEx rats as compared with SED animals. In addition, compared with the SED group, CEx animals had a lower body mass gain, and the aorta obtained from these animals had reduced contractile response to norepinephrine and greater acetylcholine-induced relaxation. These results were not observed in ACEx animals. Conclusions: Both CEx and AEx improved fitness, but only CEx led to reduced body weight gain and improved endothelial function.

Resumo Fundamento: A prática de exercícios em sessões curtas que se repetem ao longo do dia pode ser uma alternativa para tirar as pessoas da inatividade física. Objetivo: Verificar se o exercício acumulado, tal como ocorre com o treinamento com exercício contínuo, melhora a função endotelial na aorta de ratos. Métodos: Ratos Wistar machos foram divididos em 3 grupos: treinamento com exercício contínuo (ExC; 1 hora em esteira) ou com exercício acumulado (ExA; 4 sessões de 15 minutos ao longo do dia) por 5 dias/semana, durante 8 semanas, ou grupo sedentário (SED). Durante o treinamento, foram registrados o ganho de peso corporal e desempenho na esteira. No dia do sacrifício, anéis (3-5 mm) da aorta foram obtidos e montados em banho de órgãos. Resultados: Animais ExC e ExA mostraram aptidão física significativamente maior em comparação com os SED. Paralelamente, em comparação com SED, animais ExC tiveram menor ganho de massa corporal, e aortas retiradas desses animais mostraram respostas contrácteis à noradrenalina reduzidas e maior relaxamento induzido pela acetilcolina. Esses resultados não foram observados no grupo ExA. Conclusões: Tanto o ExC quanto o ExA melhoraram a aptidão física, mas somente o ExC foi capaz de reduzir o ganho de peso corporal dos animais e melhorar a função endotelial.

Airways and vascular smooth muscles relaxant activities of Gaultheria trichophylla

The aim of this experimental work was to explore the potential pharmacological activities of Gaultheria trichophylla Royle in hyperactive respiratory and vascular conditions. Gaultheria trichophylla was extracted with solvents, phytochemical detection tests were performed, and rabbit trachea and aorta strips were used to evaluate its effects on airways and vascular smooth muscles. Qualitative phytochemical tests showed the presence of flavonoids, alkaloids, anthraquinones, saponins, terpenoids, and condensed tannins. The methanol extract caused inhibition [EC[50] values of 3.12 mg/mL] of carbachol [1 micro M] and partial relaxation of K[+][80 mM] caused contractions in tracheal strips. The chloroform extract was comparatively more potent against carbachol than K[+] induced contraction with EC[50] values of 0.64 and 2.26 mg/mL, respectively. However, the n-hexane extract showed more potency against K[+] than cabachol induced contractions, as in case with verapamil, with EC[5]0 values of 0.61 and 6.58 mg/mL, respectively. In isolated prepared trachea, the extracts displaced the carbachol concentration response curves and maximum response was suppressed. In rabbit aorta preparations, methanol and n-hexane extracts partially relaxed phenylephrine [1 micro M] and K[+] induced vasoconstrictions. However, the chloroform extract inhibited phenylephrine induced contractions and exhibited a vasoconstrictor effect at lower concentrations and a relaxant effect at higher concentrations against K[+] precontractions. The data indicates that, in addition to others, the extracts of G .trichophylla possess verapamil like Ca[++] channel blocking components which explain the possible role of this plant in respiratory and vascular conditions

Tocotrienols; effects on intimal thickening in ascending aorta of cholesterol-fed rabbits

To evaluate the effect of tocotrienols on intimal thickening in ascending aorta of cholesterol-fed rabbits. Randomized control trial. The Anatomy department of Army Medical College, Rawalpindi, from March 2009 to February 2010. Thirty, male, New Zealand white rabbits were randomly divided into three equal groups. Group- I was fed normal lab diet for six weeks. For the similar period, group-II and III were given 2% high cholesterol diet. However, group-III diet was also supplemented with tocotrienols [6 mg/kg body weight/day]. By the end of study, aorta was removed from each animal. Cross sections from ascending aorta were processed and embedded in paraffin. Light microscopic examination was performed in H and E and Verhoeff elastic stained slides. Tunica intima in group-I appeared as single layer of squamous endothelial cells, lying on a thin layer of loose connective tissue. High cholesterol diet in group-II induced marked atherosclerotic changes which were characterized by extensive intimal thickening with raised fatty streaks, pools of extracellular lipids, proliferation of smooth muscles and deposition of connective tissue matrix. Intimal thickening was also observed in group-III, but lesions were of lesser degree than group-II [P<0.05]. Histomorphometric analysis revealed significantly [P<0.001] higher thickness of intima in group-II and in group-III when either was compared with group-I. However, thickness of intima was 35% lesser [P<0.05] in group-III than group-II. Tocotrienols has significant potential in suppressing the intimal thickening of aorta in cholesterol-fed rabbits

Cinnamyl alcohol attenuates vasoconstriction by activation of K+ channels via NO-cGMP-protein kinase G pathway and inhibition of Rho-kinase

Cinnamyl alcohol (CAL) is known as an antipyretic, and a recent study showed its vasodilatory activity without explaining the mechanism. Here we demonstrate the vasodilatory effect and the mechanism of action of CAL in rat thoracic aorta. The change of tension in aortic strips treated with CAL was measured in an organ bath system. In addition, vascular strips or human umbilical vein endothelial cells (HUVECs) were used for biochemical experiments such as Western blot and nitrite and cyclic guanosine monophosphate (cGMP) measurements. CAL attenuated the vasoconstriction of phenylephrine (PE, 1 microM)-precontracted aortic strips in an endothelium-dependent manner. CAL-induced vasorelaxation was inhibited by pretreatment with NG-nitro-L-arginine methyl ester (L-NAME; 10(-4) M), methylene blue (MB; 10(-5) M) and 1 H-[1,2,4]-oxadiazolole-[4,3-a] quinoxalin-10one, (ODQ; 10(-6) or 10(-7) M) in the endothelium-intact aortic strips. Atrial natriuretic peptide (ANP; 10(-8) or 10(-9) M) did not affect the vasodilatory effect of CAL. The phosphorylation of endothelial nitric oxide synthase (eNOS) and generation of nitric oxide (NO) were stimulated by CAL treatment in HUVECs and inhibited by treatment with L-NAME. In addition, cGMP and PKG1 activation in aortic strips treated with CAL were also significantly inhibited by L-NAME. Furthermore, CAL relaxed Rho-kinase activator calpeptin-precontracted aortic strips, and the vasodilatory effect of CAL was inhibited by the ATP-sensitive K+ channel inhibitor glibenclamide (Gli; 10(-5) M) and the voltage-dependent K+ channel inhibitor 4-aminopyridine (4-AP; 2 x 10(-4) M). These results suggest that CAL induces vasorelaxation by activating K+ channels via the NO-cGMP-PKG pathway and the inhibition of Rho-kinase.

Syringaresinol causes vasorelaxation by elevating nitric oxide production through the phosphorylation and dimerization of endothelial nitric oxide synthase

Nitric oxide (NO) produced by endothelial NO synthase (eNOS) plays an important role in vascular functions, including vasorelaxation. We here investigated the pharmacological effect of the natural product syringaresinol on vascular relaxation and eNOS-mediated NO production as well as its underlying biochemical mechanism in endothelial cells. Treatment of aortic rings from wild type, but not eNOS-/- mice, with syringaresinol induced endothelium-dependent relaxation, which was abolished by addition of the NOS inhibitor NG-monomethyl-L-arginine. Treatment of human endothelial cells and mouse aortic rings with syringaresinol increased NO production, which was correlated with eNOS phosphorylation via the activation of Akt and AMP kinase (AMPK) as well as elevation of intracellular Ca2+ levels. A phospholipase C (PLC) inhibitor blocked the increases in intracellular Ca2+ levels, AMPK-dependent eNOS phosphorylation, and NO production, but not Akt activation, in syringaresinol-treated endothelial cells. Syringaresinol-induced AMPK activation was inhibited by co-treatment with PLC inhibitor, Ca2+ chelator, calmodulin antagonist, and CaMKKbeta siRNA. This compound also increased eNOS dimerization, which was inhibited by a PLC inhibitor and a Ca2+-chelator. The chemicals that inhibit eNOS phosphorylation and dimerization attenuated vasorelaxation and cGMP production. These results suggest that syringaresinol induces vasorelaxation by enhancing NO production in endothelial cells via two distinct mechanisms, phosphatidylinositol 3-kinase/Akt- and PLC/Ca2+/CaMKKbeta-dependent eNOS phosphorylation and Ca2+-dependent eNOS dimerization.

The methyl ester of rosuvastatin elicited an endothelium-independent and 3-hydroxy-3-methylglutaryl coenzyme A reductase-independent relaxant effect in rat aorta

The relaxant effect of the methyl ester of rosuvastatin was evaluated on aortic rings from male Wistar rats (250-300 g, 6 rats for each experimental group) with and without endothelium precontracted with 1.0 µM phenylephrine. The methyl ester presented a slightly greater potency than rosuvastatin in relaxing aortic rings, with log IC50 values of -6.88 and -6.07 M, respectively. Unlike rosuvastatin, the effect of its methyl ester was endothelium-independent. Pretreatment with 10 µM indomethacin did not inhibit, and pretreatment with 1 mM mevalonate only modestly inhibited the relaxant effect of the methyl ester. Nω-nitro-L-arginine methyl ester (L-NAME, 10 µM), the selective nitric oxide-2 (NO-2) inhibitor 1400 W (10 µM), tetraethylammonium (TEA, 10 mM), and cycloheximide (10 µM) partially inhibited the relaxant effect of the methyl ester on endothelium-denuded aortic rings. However, the combination of TEA plus either L-NAME or cycloheximide completely inhibited the relaxant effect. Inducible NO synthase (NOS-2) was only present in endothelium-denuded aortic rings, as demonstrated by immunoblot with methyl ester-treated rings. In conclusion, whereas rosuvastatin was associated with a relaxant effect dependent on endothelium and hydroxymethylglutaryl coenzyme A reductase in rat aorta, the methyl ester of rosuvastatin exhibited an endothelium-independent and only slightly hydroxymethylglutaryl coenzyme A reductase-dependent relaxant effect. Both NO produced by NOS-2 and K+ channels are involved in the relaxant effect of the methyl ester of rosuvastatin.

Gadolinium increases the vascular reactivity of rat aortic rings

Gadolinium (Gd) blocks intra- and extracellular ATP hydrolysis. We determined whether Gd affects vascular reactivity to contractile responses to phenylephrine (PHE) by blocking aortic ectonucleoside triphosphate diphosphohydrolase (E-NTPDase). Wistar rats of both sexes (260-300 g, 23 females, 7 males) were used. Experiments were performed before and after incubation of aortic rings with 3 µM Gd. Concentration-response curves to PHE (0.1 nM to 0.1 mM) were obtained in the presence and absence of endothelium, after incubation with 100 µM L-NAME, 10 µM losartan, or 10 µM enalaprilat. Gd significantly increased the maximum response (control: 72.3 ± 3.5; Gd: 101.3 ± 6.4 percent) and sensitivity (control: 6.6 ± 0.1; Gd: 10.5 ± 2.8 percent) to PHE. To investigate the blockade of E-NTDase activity by Gd, we added 1 mM ATP to the bath. ATP reduced smooth muscle tension and Gd increased its relaxing effect (control: -33.5 ± 4.1; Gd: -47.4 ± 4.1 percent). Endothelial damage abolished the effect of Gd on the contractile responses to PHE (control: 132.6 ± 8.6; Gd: 122.4 ± 7.1 percent). L-NAME + Gd in the presence of endothelium reduced PHE contractile responses (control/L-NAME: 151.1 ± 28.8; L-NAME + Gd: 67.9 ± 19 percent AUC). ATP hydrolysis was reduced after Gd administration, which led to ATP accumulation in the nutrient solution and reduced ADP concentration, while adenosine levels remained the same. Incubation with Gd plus losartan and enalaprilat eliminated the pressor effects of Gd. Gd increased vascular reactivity to PHE regardless of the reduction of E-NTPDase activity and adenosine production. Moreover, the increased reactivity to PHE promoted by Gd was endothelium-dependent, reducing NO bioavailability and involving an increased stimulation of angiotensin-converting enzyme and angiotensin II AT1 receptors.

Efecto del sulodexide sobre la capacidad de relajación y alteraciones estructurales de la arteria aorta en ratas diabéticas por estreptozotocina / Effect of sulodexide on aortic vasodilation capacity and associated morphological changes in rats with streptozotocin-induced diabetes

La disfunción endotelial (DE) se presenta en pacientes con hipercolesterolemia, hipertensión arterial, obesidad y diabetes mellitus. Evidencias sugieren un papel de los glicosaminoglicanos en la DE. Evaluamos el efecto del sulodexide (SLD), un glicosaminoglicano utilizado en el tratamiento de la albuminuria y la enfermedad isquémica en pacientes diabéticos, sobre la relajación arterial y los cambios morfológicos en un modelo experimental de diabetes tipo 1. La diabetes se indujo a ratas Sprague Dawley administrando estreptozotocina (STZ), 60 mg/kg, i.v. Los animales fueron distribuidos en los siguientes grupos: I= control, II= diabéticas, III: control + sulodexide, IV= diabéticas + sulodexide (15 mg/kg/día s.c). A los 3 meses fueron sacrificados, las aortas extraídas para evaluar la relajación vascular inducida por acetilcolina (Ach) y nitroprusiato de sodio en anillos precontraídos con fenilefrina. Fueron evaluadas histológicamente mediante microscopía de luz y coloraciones diversas. El SLD in vitro no modificó la tensión basal de los anillos arteriales en reposo o precontraídos con fenilefrina. La diabetes disminuyó la capacidad de relajación arterial en respuesta a la Ach en un 28,8-35,1% vs control, efecto que fue prevenido por SLD. No se observó diferencia significativa en la relajación inducida por nitroprusiato sódico entre los grupos. El estudio histológico en los animales diabéticos mostró alteraciones estructurales, particularmente en la íntima y la adventicia, cambios que fueron prevenidos por el tratamiento con SLD. Nuestros resultados apoyan la potencial utilidad terapéutica del SLD en el tratamiento de la disfunción endotelial.

Endothelial dysfunction (ED) is observed in patients with hypercholesterolemia, arterial hypertension, obesity and diabetes mellitus. Recent evidences suggest the involvement of glycosaminoglycans(GSG) in ED. We evaluated the effect of sulodexide (SLD), a natural GSG used in albuminuria and ischemic diabetes treatment, on arterial relaxation and vascular morphological changes in a diabetic type I model. Diabetes was induced, in Sprague-Dawley rats by streptozotocine (STZ) administration, 60 mg, iv. Rats were divided into four groups; I: control, II: diabetics, III: control + SLD, IV: diabetics treated with SLD (15 mg/day). After three months, phenylephrine precontracted aortic rings were used to evaluate acetylcholine (ACh) and sodium nitroprusside (NPS) relaxation capacities. Light microscopy of aorta was done with several staining procedures. In vitro, SLD did not change smooth muscle tone in resting or phenylephrine precontracted aortic rings. In diabetic rats, ACh relaxation was 28.8-35.1% lower than in control rats. Diabetic rats treated with SLD showed aortic ACh relaxation similar to control rats. No significative statistical difference was found in endothelium-independent NPS relaxation, between the different groups. Light microscopy histological studies revealed important morphological alterations, particularly in intima and adventitia layers of aortic artery; those changes were dramatically reversed in SLD treated rats. Our experiments support the conclusion that SLD is a potential drug for improving endothelial dysfunction in diabetes.

Vosodilator effect of pelargonium odoratissimum on isolated rat aorta

The vasodilator effect of Pelargonium odoratissimum was investigated using isolated rat aortic rings. Eethanolic extract has shown a profound relaxing effect on noradrenaline-precontracted aortic rings. There was a difference in the effect in the absence or presence of endothelium. Relaxing effect of the ethanolic extract was obviously more potent in the presence of endothelium. These data clearly indicate that relaxing effect of Pelargonium odoratissimum is partially endothelium-dependent

Synthesis and effects of novel dihydropyridines as dual calcium channel blocker and angiotensin antagonist on isolated rat aorta

Four novel losartan analogues 5a-d were synthesized by connecting a dihydropyridine nucleus to imidazole ring. The effects of 5a and 5b on angiotensin receptors [AT1] and L-type calcium channels were investigated on isolated rat aorta. Aortic rings were pre-contracted with 1 microM Angiotensin II or 80 mM KC1 and relaxant effects of losartan, nifedipine, 5a and 5b were evaluated by cumulative addition of these drugs to the bath solution. The results showed that compounds 5a and 5b have both L-type calcium channel and AT1 receptor blocking activity. Their effects on AT1 receptors are 1000 and 100, 000 times more than losartan respectively. The activity of compound 5b on L-type calcium channel is significantly less than nifedipine but compound 5a has comparable effect with nifedipine. Finally we concluded that these two new Compounds can be potential candidates to be used as effective antihypertensive agents

Piceatannol-3'-O-beta-D-glucopyranoside as an active component of rhubarb activates endothelial nitric oxide synthase through inhibition of arginase activity

Arginase competitively inhibits nitric oxide synthase (NOS) via use of the common substrate L-arginine. Arginase II has recently reported as a novel therapeutic target for the treatment of cardiovascular diseases such as atherosclerosis. Here, we demonstrate that piceatannol-3'-O-beta-D-glucopyranoside (PG), a potent component of stilbenes, inhibits the activity of arginase I and II prepared from mouse liver and kidney lysates, respectively, in a dose-dependent manner. In human umbilical vein endothelial cells, incubation of PG markedly blocked arginase activity and increased NOx production, as measured by Griess assay. The PG effect was associated with increase of eNOS dimer ratio, although the protein levels of arginase II or eNOS were not changed. Furthermore, isolated mice aortic rings treated with PG showed inhibited arginase activity that resulted in increased nitric oxide (NO) production upto 78%, as measured using 4-amino-5-methylamino-2',7'-difluorescein (DAF-FM) and a decreased superoxide anions up to 63%, as measured using dihydroethidine (DHE) in the intact endothelium. PG showed IC50 value of 11.22 microM and 11.06 microM against arginase I and II, respectively. PG as an arginase inhibitor, therefore, represents a novel molecule for the therapy of cardiovascular diseases derived from endothelial dysfunction and may be used for the design of pharmaceutical compounds.

New nitric oxide donors based on ruthenium complexes

Nitric oxide (NO) donors produce NO-related activity when applied to biological systems. Among its diverse functions, NO has been implicated in vascular smooth muscle relaxation. Despite the great importance of NO in biological systems, its pharmacological and physiological studies have been limited due to its high reactivity and short half-life. In this review we will focus on our recent investigations of nitrosyl ruthenium complexes as NO-delivery agents and their effects on vascular smooth muscle cell relaxation. The high affinity of ruthenium for NO is a marked feature of its chemistry. The main signaling pathway responsible for the vascular relaxation induced by NO involves the activation of soluble guanylyl-cyclase, with subsequent accumulation of cGMP and activation of cGMP-dependent protein kinase. This in turn can activate several proteins such as K+ channels as well as induce vasodilatation by a decrease in cytosolic Ca2+. Oxidative stress and associated oxidative damage are mediators of vascular damage in several cardiovascular diseases, including hypertension. The increased production of the superoxide anion (O2-) by the vascular wall has been observed in different animal models of hypertension. Vascular relaxation to the endogenous NO-related response or to NO released from NO deliverers is impaired in vessels from renal hypertensive (2K-1C) rats. A growing amount of evidence supports the possibility that increased NO inactivation by excess O2- may account for the decreased NO bioavailability and vascular dysfunction in hypertension.