Employment of a Collagen Conduit Soaked in an Angiogenic Fraction Derived from Natural Latex in the Regeneration of Sciatic Nerve of Rats

AbstractPeripheral nerve injuries are very frequent in medical practice and although the use of autografts remains the standard procedure to repair the gap between the proximal and distal stumps, alternative techniques have been proposed to avoid complications to the donor site and speed up the nerve regeneration process. A membrane produced from natural latex has been used successfully both experimentally (angioplasties, esophagus neoformation, reconstruction of the ocular conjunctiva) and clinically (myringoplasties, treatment of skin ulcers), showing angiogenic potential and leading to tissue neoformation. The purpose of this study is to evaluate the capacity of a conduit made with collagen and soaked in an angiogenic protein extracted from latex in accelerating and improving the regeneration after surgically sectioning the rat sciatic nerve. Adult Wistar male rats had the sciatic nerve sectioned under anesthesia with a subtraction of a 10mm nerve fragment. Then they received an autograft implant (inverted nerve fragment) or the interposition into the nerve gap of a tube made up of that collagen and soaked in an angiogenic fraction derived from natural latex. At the endpoint of the experiments, the animals were submitted to neurological function evaluation, and killed by an overdose of anesthesia and exsanguination. The implants (collagen conduit or autograft) and the tibialis and gastrocnemius muscles were removed, fixed and processed with embedding in resin. Cross-section of implants and muscles were performed and prepared in histological slides to observation under light microscopy. Functional recovery was correlated with histopathological analysis. Bot

Sciatic nerve regeneration in rats by a nerve conduit engineering with a membrane derived from natural latex Regeneração do nervo ciático em ratos através de um conduto confeccionado com uma membrana de látex natural

PURPOSE: To evaluate the capacity of natural latex membrane to accelerate and improve the regeneration quality of the of rat sciatic nerves. METHODS: Forty male adult Wistar rats were used, anesthetized and operated to cut the sciatic nerve and receive an autograft or a conduit made with a membrane derived from natural latex (Hevea brasiliensis). Four or eight weeks after surgery, to investigate motor nerve recovery, we analyzed the neurological function by walking pattern (footprints analysis and computerized treadmill), electrophysiological evaluation and histological analysis of regenerated nerve (autologous nerve graft or tissue cables between the nerve stumps), and anterior tibial and gastrocnemius muscles. RESULTS: All functional and morphological analysis showed that the rats transplanted with latex conduit had a better neurological recovery than those operated with autologous nerve: quality of footprints, performance on treadmill (p<0.01), electrophysiological response (p<0.05), and quality of histological aspects on neural regeneration. CONCLUSION: The data reported showed behavioral and functional recovery in rats implanted with latex conduit for sciatic nerve repair, supporting a complete morphological and physiological regeneration of the nerve.<br>OBJETIVO: Avaliar a capacidade de uma membrana de látex natural em acelerar e melhorar a qualidade da regeneração do nervo ciático seccionado de ratos. MÉTODOS: Foram utilizados 40 ratos machos adultos da linhagem Wistar, anestesiados e operados com autoenxerto ou com interposição de um tubo confeccionado com uma membrana derivada do latex natural (Havea brasiliensis). Quatro ou oito semanas após a cirurgia, para investigar a recuperação motora do nervo, foram analisadas a função neurológica através do padrão da marcha (análise das pegadas e esteira computadorizada), avaliação eletrofisiológica e análise histológica do nervo regenerado (enxerto de nervo autólogo ou formação de nervo novo entre os cotos nervosos) e músculos gastrocnêmio e tibial anterior. RESULTADOS: Todas as análises morfológicas e funcionais demonstraram que os ratos transplantados com o conduto de látex tiveram recuperação melhor do que aqueles operados com nervo autólogo: qualidade das pegadas impressas, desempenho em esteira (p<0,01), resposta eletrofisiológica (p<0,05), e qualidade histológica da regeneração nervosa. CONCLUSÃO: Os dados apresentados demonstraram recuperação comportamental e funcional nos ratos implantados com o conduto de látex para a reparação do nervo ciático por meio de uma completa regeneração morfológica e fisiológica do nervo