Armando dos Santos Cunha

A utilização do tubo de ácido poliglicólico e FK506 na regeneração de nervos periféricos

Extensive losses of neural tissue preclude the repair performed by means of primary anastomosis. In those cases, nerve autograft is considered as the treatment of choice. The synthetic tube constituted by polyglycoic acid is an option for nerve graft. The FK506 is an immunosuppressive agent, which increases the neural regeneration rates in vivo and in vitro. The purpose of this study was to compare, in rats, the degree of neural regeneration, by using histological analysis, a count of the number of regenerated myelinated axons, and a functional analysis, obtained by interposing the autogenous graft (group A), polyglycoic acid tube (group B) and a combination of polyglycoic acid tube with FK506 (group C) in 5-cm defects of the sciatic nerve. Neuroma formation was observed only in group A. Groups B and C presented similar histological patterns. The quantitative analysis of the number of regenerated myelinated axons has determined that: 1) group B presented, in average, a lower number when compared to the other groups; 2) there was no significant difference between control group A and group C. For functional recovery, there was no statistically significant change between the three groups, despite the qualitative and quantitative histological differences seen.

Effect of hyperbaric oxygen on the regeneration of experimental crush injuries of nerves

Hyperbaric oxygen has been successfully used on treatment of acute ischemic injuries involving soft tissues and chronic injuries. In nerve crush injuries, the mechanisms involved are very similar to those found in ischemic injuries. Consequently, it is logical to hypothesize that hyperbaric oxygen should improve nerve repair, which is a critical step on functional recovery. In the present study, we created standard nerve crush injuries on sciatic nerves of rats, which underwent treatment with hyperbaric oxygen. Results were assessed by functional evaluation using walking-track analysis. The functional recovery indexes observed did not differ from control group. We concluded that hyperbaric oxygen therapy, in the schedule used, had no influence on functional recovery after nerve crush injuries.

Tubo de ácido poliglicólico e GM1 na regeneração de nervos periféricos

INTRODUCAO: A auto-enxertia de nervo e considerada tratamento de escolha nas grandes perdas de tecido neural que nao permitam a reparacao atraves de anastomose primaria. Nesses casos, o tubo sintetico a base de acido poliglicolico e uma alternativa para enxertia de nervo. Por outro lado, muitos estudos tem enfatizado a importância dos fatores neurotroficos na regeneracao neural: o monossialotetraesosilgangliosideo (GM1), um dos principais glicoesfingolipides do tecido nervoso de mamiferos, e tido como potencializador dos efeitos desses fatores. OBJETIVO: Comparar, em ratos, o grau de regeneracao neural, utilizando analise histologica, contagem do numero de axonios mielinizados regenerados e analise funcional com a utilizacao do neurotubo e do GM1. METODOS: Essa avaliacao foi obtida com a interposicao de enxerto autogeno (grupo A), tubo de acido poliglicolico (grupo B) e da associacao do tubo de acido poliglicolico a administracao de GM1 (grupo C) em defeitos de 5 mm no nervo ciatico. RESULTADOS: Foi observada formacao de neuroma apenas no grupo A. Os grupos A e C apresentaram padroes histologicos semelhantes, exceto que os axonios regenerados do grupo C apresentavam-se mais organizados e mielinizados que o grupo A. CONCLUSAO: Na recuperacao funcional, nao houve diferenca estatisticamente significativa entre os tres grupos, a despeito das diferencas histologicas qualitativas e quantitativas verificadas.

Peroneal nerve reconstruction by using glycerol-preserved veins: histological and functional assessment in rats

PURPOSE To compare the degree of neural regeneration in rats upon interposition of autologous nerve graft, autogenous vein, glycerol-preserved autogenous vein, and glycerol-preserved allogeneic vein using qualitative and quantitative histological analyses as well as functional assessments. METHODS Peroneal nerves were reconstructed differently in four groups of animals. Functional assessments were performed pre- and postoperatively for a period of six weeks. After six weeks, the animals were sacrificed and histological evaluations were performed. RESULTS Histological patterns of autogenous veins without preservation showed pronounced neoangiogenesis and extensive axonal rarefaction, as confirmed by axonal counting and functional assessments. Glycerol-preserved veins had results similar to the control. CONCLUSIONS Glycerol-preserved autogenous or allogeneic veins showed similar results to autograft results. The autogenous vein (without preservation in glycerol) presented histological and functional outcomes statistically lower than other groups.