Modelo de degeneración del disco intervertebral por punción de la cola de ratas Wistar: evaluación histológica y radiográfica

OBJETIVO: descrever a caracterização histológica e radiográfica do método de indução da degeneração do disco intervertebral da cauda de ratos Wistar induzida por meio de punção. MÉTODOS: ratos Wistar machos adultos foram anestesiados, radiografados e submetidos à punção dos discos intervertebrais localizados entre a sexta e a sétima e a oitava e nona vértebras coccígeas. Para a punção foi utilizada agulha de 20G, que foi introduzida até o ânulo fibroso, e foi realizada dupla rotação de 360º, mantendo-se a mesma posição durante 30 segundos antes da retirada. O disco intermediário aos segmentos lesados (7-8) não foi puncionado e foi utilizado como controle. Foi selecionado o período pós-lesão de 30 dias (n=9) para sacrifício e análise dos discos intervertebrais. Os animais foram radiografados 30 dias após a lesão para análise da altura do disco intervertebral. Os segmentos da cauda foram removidos, fixados e desmineralizados, processados e corados com Hematoxilina-Eosina para avaliação histológica. RESULTADOS: a análise radiográfica revelou a redução significativa da altura dos discos lesados em relação ao controle. A avaliação histológica revelou alterações no núcleo pulposo e ânulo fibroso dos discos lesados em relação ao controle. Não foram observadas diferenças na intensidade de lesão entre os discos proximal e distal. CONCLUSÃO: a degeneração do disco intervertebral da cauda de ratos Wistar induzida por meio de punção mostrou ser método reprodutível para estudo da degeneração do disco intervertebral. Esse modelo mostrou validade para avaliação experimental de novas intervenções terapêuticas nos processos de degeneração do disco intervertebral.OBJECTIVE: to report the induction of intervertebral disc degeneration of the rat caudal spine by needle puncture and its radiographic and histologic characterization. METHODS: adult male Wistar rats were anesthetized, submitted to the X-Ray and then to the needle puncture (20G) of intervertebral disc between the sixth and seventh (proximal segment) and the eighth and ninth (distal segment) coccygeal vertebrae. Radiographies were taken 30 days after lesion for analysis of intervertebral disc height. The intermediate disc (7-8) to injured segments was not punctured and was considered as control. All segments were removed, fixed and demineralized, processed and stained with Hematoxylin-Eosin for histological evaluation. RESULTS: radiographic analysis revealed significant reduction in disc height of lesioned discs compared to control. Similarly, histological analysis revealed significant changes in the nucleus pulposus and annulus fibrosus of the lesioned discs (proximal and distal) relative to the control. There was no difference in the intensity of injury between the proximal and distal discs. CONCLUSION: the experimental model of tail intervertebral disc degeneration by needle puncture reproduced the steps of the intervertebral disc degeneration, assessed by different instruments, and it can be used for experimental evaluation of new therapeutic interventions for intervertebral disc degeneration process.OBJETIVO: describir la caracterización histológica y radiográfica del método de inducción de la degeneración del disco intervertebral de la cola de ratas Wistar, inducida por medio de la punción. MÉTODOS: ratas Wistar machos adultos fueron anestesiados, radiografiados y sometidos a la punción de los discos intervertebrales localizados, entre la sexta y la séptima; y la octava y novena vértebras coccígeas. Para la punción, fue utilizada una aguja de 20G, que fue introducida hasta el ánulo fibroso, y fue realizada una dupla rotación de 360º, manteniendo esta posición durante 30 segundos, previamente a la retirada. El disco intermediario a los segmentos lesionados (7-8) no fue puncionado y fue considerado como control. Fue seleccionado el periodo post-lesión de 30 días (n=9) para sacrificio y análisis de los discos intervertebrales. Los animales fueron radiografiados 30 días después de la lesión para análisis de la altura del disco intervertebral. Los segmentos de la cola fueron removidos, fijados y desmineralizados, procesados y coloreados con hematoxilina-eosina para evaluación histológica. RESULTADOS: el análisis radiográfico mostró una reducción significativa de la altura de los discos lesionados en relación al control. La evaluación histológica mostró alteraciones en el núcleo pulposo y el ánulo fibroso de los discos lesionados en relación al control. No fueron observadas diferencias en la intensidad de la lesión entre los discos proximal y distal. CONCLUSIÓNES: la degeneración del disco intervertebral de la cola de ratas Wistar inducida por medio de punción mostró ser un método reproducible para el estudio de la degeneración del disco intervertebral. Ese modelo mostró validez para la evaluación experimental de nuevas intervenciones terapéuticas en los procesos de la degeneración del disco intervertebral.Capes - PNPDFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Computer dynamics to evaluate blood flow through the modified Blalock-Taussig shunt

OBJECTIVES: To study the influence of geometric factors upon the function of modified Blalock-Taussig anastomoses (mBT) using a computational dynamic code based upon the method of finite elements. METHODS: The mBT operation, performed in 10 patients, was graphically reconstructed to create a parametric 3-dimensional geometric model. Using Streamline Upwind/Petrov-Galerkin approximations, blood flow and distribution were evaluated in different diameters of subclavian arteries and polytetrafluoroethylene grafts (PTFE) and angles of proximal anastomoses. RESULTS: The percentage of blood flow derived through the PTFE grows as its diameter increases in relation to subclavian artery diameter. Variations in the PTFE diameter do not interfere with pulmonary artery flow distribution. An angle of 110º in proximal anastomoses results in a high percentage of blood derivation to the graft, while angles of 30º, 60ºand 90º present with almost similar flow rates. However, angles of 30º and 110º produce an excessive flow to one of the pulmonary arteries, in detriment of the other. Peak pressure in the PTFE is affected by the proximal angle of anastomosis, with 30º resulting in higher and 110º in lower values. As the angle increases, the region of higher pressure shifts from the PTFE to subclavian artery. CONCLUSION: In the experimental model, percentage of flow derived in the PTFE is directly related to the diameter of the graft. The ratio between the diameters of subclavian artery and graft is an important regulator of flow deviation to the anastomosis. Angles of the anastomosis between the subclavian artery and the PTFE of 60º to 90º result in favorable pulmonary artery flow distribution and the location of the peak pressure

Ayahuasca alters structural parameters of the rat aorta

Ayahuasca is a hallucinogenic brew traditionally used by Northwestern Amazonian indigenous groups for therapeutic purposes. It is prepared by the decoction of Banisteriopsis caapi with the leaves of Psychotria viridis. Banisteriopsis caapi contains β-carbolines that are inhibitors of monoamine oxidase and P. viris is rich in dimethyltryptamine, a 5-HT(1A/2A/2C) agonist. Acute ayahuasca administration produces moderate cardiovascular effects in healthy volunteers, but information regarding long-term use is lacking. This study investigated the effects of ayahuasca (2-4 mL/kg) in the rat aorta after acute and chronic (14 days) administration. Ayahuasca caused flattening and stretching of vascular smooth muscle cells and changes in the arrangement and distribution of collagen and elastic fibers. Chronic treatment with the higher dose significantly increased media thickness and the ratio of media thickness to lumen diameter. More research is needed on the cardiovascular function of long-term ayahuasca consumers