ABSTRACT
Existen evidencias que asocian biomarcadores inflamatorios con síndrome metabólico (SM), insulinoresistencia y enfermedad aterogénica subclínica (ATS), pero no está clara su interrelación y como contribuirían al desarrollo de estas patologías multisindrómicas. El componente inflamatorio sería la vía final común reflejada por la disfunción endotelial y la inducción de estrés oxidativo. Se diseñó un modelo experimental de SM mediante la administración de fructuosa al 10% diluída en agua de bebida por 6 semanas y de ATS inducida por hiperfibrinogenemia (HF) en diferentes períodos experimentales. Se determinó en todos los grupos estudiados: glucemia, insulinemia, perfil lipídico, cálculo de HOMA (homeostasis model assessment) y se cuantificaron por espectrofotometría biomarcadores inflamatorios y de estrés oxidativo: fibrinógeno, oxido nítrico (NO), L-citrulina, adiponectina y superóxido dismutasa (SOD). Se analizó por microscopia óptica la anatomía patológica de aorta torácica e hígado. Se determinaron las probables alteraciones morfológicas mitocondriales en células musculares lisas aórticas por microscopia electrónica y para valorar funcionalidad se determinó la actividad enzimática de Citrato Sintasa y los complejos I, II, III y IV de la cadena respiratoria mitocondrial.
SUMMARY: There is evidence to associate inflammatory biomarkers with metabolic syndrome (MS), insulin resistance and atherogenic subclinical disease (ASD), but it is unclear their interrelationship and how would it contribute to the development and progression of these multisindromical pathologies. The inflammatory component would be the final common pathway reflected by endothelial dysfunction and induction of oxidative stress. An experimental model of MS was designed by administering diluted fructose to 10% in drinking water for6 weeks and ASD induced by hyperfibrinogenemia (HF) in different experimental periods. Glucose, insulin, lipid profile and HOMA calculation (homeostasis model assessment) was determined in all groups studied. Inflammatory and oxidative stress biomarkers: fibrinogen, nitric oxide (NO), L-citrulline, adiponectin and superoxide dismutase (SOD) were quantified by spectrophotometry. Thoracic aorta and liver histopathology were analyzed by optical microscopy. Probable mitochondrial morphological changes in aortic smooth muscle cells were determined by electron microscopy and functional alterations were measured by the enzymatic activity of citrate synthase and complex I, II, III and IV of the mitochondrial respiratory chain.
Subject(s)
Male , Animals , Female , Mice , Animals , Atherosclerosis/metabolism , Coronary Artery Disease , Mitochondrial Diseases , ArgentinaABSTRACT
Con el propósito de estudiar el efecto de la vitamina E sobre el estrés oxidativo desencade- nado por hiperfibrinogenemia (HF) en un modelo experimental de aterogénesis y la posible normalización de los indicadores de estrés oxidativo, se evaluaron: óxido nítrico (NO), L-citrulina, superóxido dismutasa (SOD) e involución de lesiones histopatológicas en la aorta torácica. El estudio se realizó en 36 ratas, cepa Wistar, que se dividieron en tres grupos (n = 12 cada uno): A, control; B, HF × 90 días; C, HF × 90 días + vitamina E. La HF se indujo mediante inyecciones de adrenalina (0,1 ml/día/rata) por 90 días. La dosis de vitamina E fue de 2 mg/día/rata durante 75 días. Se dosaron en plasma los niveles de fibrinógeno (mg/dl), NO (uM) y L-citrulina (mM) y en lisado de glóbulos rojos, por espectrofotometría, se determinó la actividad de la SOD (U/ml). Se analizaron cortes de la aorta torácica por microscopia óptica (MO). Para el análisis estadístico se emplearon MANOVA y la prueba de Fisher; se estableció un nivel de significación de p < 0,05. Se observó un aumento significativo de fibrinógeno en el grupo B (407 ± 8,9 mg/dl) en comparación con los grupos A (203 ± 9 mg/dl) y C (191,58 ± 17,79 mg/dl) (p < 0,001). El NO disminuyó significativamente en el grupo B (13,73 ± 1,76 uM) frente a los grupos A (23,58 ± 0,08 uM) y C (26,64 ± 3,65 uM) (p < 0,001). La L-citrulina aumentó en forma significativa en los grupos B (4,99 ± 0,18 mM) y C (6,60 ± 0,16 mM) en comparación con el grupo A (3,03 ± 0,13 mM) (p < 0,001). El SOD incrementó su actividad en los grupos B (251,67 ± 10,34 U/ml) y C (304,75 ± 10,43 U/ml) frente al grupo A (139,44 ± 4,74 U/ml) (p < 0,001). La microscopia óptica mostró denudación endotelial, engrosamiento intimal y protrusión de la pared en el grupo B (90%) y recuperación de la denudación endotelial y disminución del 50% del engrosamiento intimal en el grupo C (p < 0,001). Niveles aumentados de SOD serían insuficientes para impedir alteraciones en la vía del estrés oxidativo inducido por la HF. La vitamina E actuaría deteniendo la reacción en cadena iniciada por los radicales libres y en consecuencia disminuiría el anión superóxido, estimulando de esta manera un incremento en la biodisponibilidad del NO y normalizando las concentraciones de fibrinógeno plasmático.
We used an experimental model of atherogenesis to evaluate the effect of vitamin E on oxidative stress induced by hyperfibrinogenemia (HF) and the possible normalization of oxidative stress markers. The following variables were studied: nitric oxide (NO), L-citrulline, superoxide dismutase (SOD) activity and regression of histopathological lesions in the thoracic aorta. The study was performed in 36 Wistar rats that were divided into three groups of 12 rats each: A, control group; B, HF for 90 days; C, HF for 90 days + vitamin E. Hyperfibrinogenemia was induced by the injection of epinephrine (0.1 ml/day/rat) during 90 days. The dose of vitamin E was 2 mg/day/rat during 75 days. We measured the plasma levels of fibrinogen (mg/dl), NO (uM) and L-citrulline (mM); SOD activity (U/ml) was assayed in red cell lysates using spectrophotometry. The histopathological sections of the thoracic aorta were examined using light microscopy (LM). Statistical analysis was performed using MANOVA and Fisher's test; a p value <0.05 was considered statistically significant. Rats in group B had a significant increase in fibrinogen levels B (407±8.9 mg/dl) compared to groups A (203±9 mg/dl) and C (191.58±17.79 mg/dl) (p<0.001). We observed a significant decrease in NO in group B (13.73±1.76 uM) versus groups A (23.58±0.08 uM) and C (26.64±3.65 uM) (p<0.001). L-citrulline increased significantly in groups B (4.99±0.18 mM) and C (6.60±0.16 mM) compared to group A (3.03±0.13 mM) (p<0.001). SOD activity was greater in groups B (251.67±10.34 U/ml) and C (304.75±10.43 U/ml) versus group A (139.44±4.74 U/ml) (p<0.001). Light microscopic examination revealed the presence of endothelial denudation, intimal thickening and vessel wall protrusion in group B (90%), while recovery of endothelial denudation and a 50% reduction in intimal thickening was observed in group C (p<0.001). High SOD activity might be insufficient to prevent abnormalities in the oxidative stress pathway induced by HF. Vitamin E would stop the chain reaction initiated by free radicals and thus decrease the superoxide anion, stimulating the bioavailability of NO with normalization of fibrinogen plasma levels.
ABSTRACT
INTRODUCTION: We studied plasmatic TNF-alpha, nitric oxide (NO) and citrulline behaviors and probable morphological mitochondrial alterations in aortic smooth muscle cells, in rats with atherogenesis induced by hyperfibrinogenemia in: A) control, B) multiple injured for 30 days and C) multiple injured for 60 days. MATERIAL AND METHODS: Hyperfibrinogenemia induction: adrenaline injection (0,1 mg/rat/day). TNF-alpha (pg/dL) was determined by Elisa and NO (microM) and citrulline (mM) by spectrophotometry. Morphological mitochondrial alterations were studied by electronic microscopy. Variables were analized: ANOVA, r coefficient and chi2 test. RESULTS: We observed a significant increment of TNF-alpha in multiple injured for 30 days (B) (50.05 +/- 2.29) as well as in multiple injured for 60 days (C) (74.99 +/- 2.82) related to control (A) (33.01 +/- 1.49) (p<0.001 in both groups). Citrulline presented a significant increased in (B) (5.56 +/- 0.20) and (C) (6.84 +/- 0.13) when compared to (A) (4.41 +/- 0.23) (p<0.001 in both situations). Mean while NO biodisponibility diminished significantly in (B) (8.97 +/- 0.70) and in (C) (5.32 +/- 0.68) when compared to (A) (21.65 +/- 1.74) (p<0.001 in both situations). CONCLUSIONS: Hyperfibrinogenemia could modify the NO physiopathological pathway and produced morphological mitochondrial alterations in aortic smooth muscle cells, probably producing ischemic lesions in the vascular wall and altering the vasodilatation response.