RESUMO
The loss of the modulator role of the endothelium could be involved in the pathogenesis of diabetic vascular complications. Transition metal compounds, such as tungsten and vanadium, have been proposed as possible agents in the treatment of diabetes by simulating the effects of insulin. The mesenteric vascular bed intervenes in vascular resistance and is a source of vasoactive compounds, such as prostanoids. The aim of this work was to study the effects of sodium tungstate and vanadyl sulphate treatments on the metabolic parameters and the release of prostanoids of the mesenteric vascular bed in an experimental model of Streptozotocin-induced diabetes. In diabetic rats, a significant increase was observed in plasma levels of glucose, triglycerides and total cholesterol. On the other hand, there was a significant reduction in the release of vasodilator prostanoids, such as prostacyclin and prostaglandin E2 and vasoconstrictor thromboxane A2 through the mesenteric vascular bed. Both sodium tungstate and vanadyl sulphate normalised glycaemia, triglyceridaemia and cholesterolaemia in rats diabetics. On the other hand, only treatment with sodium tungstate reversed the reduction in the release of vasodilator prostanoids, improving in diabetic animals the prostacyclin/thromboxane ratio, an indicator of vascular dysfunction. In conclusion, unlike vanadyl sulphate, sodium tungstate is shown to be more effective in controlling metabolic changes and the production of vasodilator prostanoids observed in experimental diabetes induced by streptozotocin.
Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Prostaglandinas/metabolismo , Compostos de Tungstênio/farmacologia , Compostos de Vanádio/farmacologia , Animais , Glicemia/efeitos dos fármacos , Diabetes Mellitus Experimental/fisiopatologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/patologia , Hipoglicemiantes/farmacologia , Masculino , Mesentério/irrigação sanguínea , Ratos , Ratos Wistar , EstreptozocinaRESUMO
Objetivo do presente estudo foi avaliar algumas propriedades físicas, químicas, comportamento biológico em tecido subcutâneo de ratos e caracterísitcas superficiais do cimento Portland (CP) associado a diferentes radiopacificadores (óxido de bismuto (OB), tungstato de cálcio (TC) e óxido de zircônio (OZ). As propriedades físicas analisadas foram radiopacidade, tempo de presa, solubilidade e características superficiais, enquanto que às químicas foram pH e liberação de ions cálcio, e a biocompatibilidade foi analisada in vivo em tecido subcutâneo de rato. A metodologia para a realização das propriedades físicas, foram as recomendadas pela ISO 6876/2001 e n.57 ADA/2000, com pequena modificação para o tempo de presa que além da agulha com peso de l00g foi utilizado também agulha com peso de 453,6 para determinação do tempo de presa final conforme norma da ASTM. As características superficiais foram realizadas em microscopia eletrônica de varredura. Para o pH e liberação de íons cálcio, os materiais foram acondicionados em dente de acrílico com cavidades retrógradas e imersos em 15 mL de água MilliQ. Nos períodos de 3, 24, 72 e 168 horas os dentes eram trocados de frasco e mensurou-se seu pH por meio de pHmetro e cálcio com uso de espectrofotômetro de absorção atômica da água que o material estava imerso. Para a biocompatibilidade os materiais foram colocados em tubos de polietileno e implantados no dorso de 15 ratos, que foram mortos após 7, 15 e 30 dias da implantação. Os dados foram comparados estatisitcamente pelo teste de Kruskal-Wallis e Miller ou ANOVA e tukey, dependendo da normalidade ou não dos dados, sendo empregado nível de significância foi de 5%. Os resultados mostraram diferença significante (P<0,05) para o tempo de presa inicial entre todos os materiais, enquanto que no tempo de presa final só não ocorreu diferença (P>0,05) entre o óxido de bismuto e tungstato de cálcio...
The aims of this study were to evaluate some physicochemical properties, subcutaneous tissue response and scanning electron microscope surface characteristics related to Portland cementassociated with the following radiopacifiersagents: bismuth oxide (BO), calcium tungstate (CT) and zirconium oxide (ZO). The physical properties evaluated were: radiopacity, setting time, solubility and scanning electron microscope study of the cements surface. The chemical properties evaluated were: pH and calcium íon release. The biocompatibility test was performed in subcutaneous tissue of rats. For the study of the physical properties, the methodologies ISO 6876/2001 e n.57 ADA/2000SO with slight variations for the setting time test were used. For the setting time test the 100g needle was used. Determination of the final setting time was performed also using the 453,6g needle according to the ASTM criteria. The surface characteristics were studied using scanning electron microscopy. For the pH and calcium ion release tests, the samples were inserted into root-end cavities prepared in acrylic teeth. Immediately, after being filled, all specimens were immersed in 15 mL of Milli-Q water. Evaluations were performed at periods of 3 hours, 24 hours, 72 hours, and 168 hours for assessment of the pH and calcium ion release. After each measurement, the specimens were moved to new tubes containing fresh MiIIi-Q water. The measurements were carried out using a pH meter. The calcium ions release was measured using an atomic absorption spectrophotometer equipped with a calcium-specific hollow cathode lamp. To evaluate the biocompatibility polyethylene tubes were filled with the samples and implanted into the subcutaneous tissue of 15 rats. The biological response was evaluated at 7, 15 and 30 days. The data was statistically compared using the kruskal-wlilis and Miller test or by using the ANOVA-Tukey test, according to the presence or absence of normal distribution...