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.

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.

Avaliação macroscópica, microscópica e histomorfométrica do tecido cicatricial pós-cirúrgico de eqüinos submetidos a duas técnicas de neurectomia digital / Macroscopic, microscopic, and histomorphometric evaluation of post-operative scar tissue in horses submitted to two techniques for digital neurectomy

Avaliou-se macro e microscopicamente o tecido cicatricial pós-operatório de eqüinos submetidos a duas técnicas de neurectomia digital: guilhotina (TG) e stripping (TS). Decorridos 14 meses das cirurgias, foram colhidas 32 amostras de tecido cicatricial em quatro éguas, que tiveram os membros submetidos a ambas as técnicas. À macroscopia, verificaram-se as dimensões da cicatriz do coto proximal e a distância entre os cotos proximal e distal. À microscopia, foi quantificada a proporção de tecido nervoso regenerado por meio de histomorfometria. Não houve diferença nas dimensões do tecido cicatricial, contudo a distância entre cotos foi 5,6 vezes maior na TS (P<0,001). Histologicamente, observou-se a presença de tecido conjuntivo frouxo e denso, macrófagos e fibras nervosas delgadas em ambas as técnicas cirúrgicas. Estruturas nodulares, compostas por fascículos nervosos, foram visualizadas em 56,2 por cento (9/16) das amostras colhidas em nervos submetidos à TS. As porcentagens médias de tecido nervoso no tecido cicatricial foram de 0,31 por cento na TG e 2,6 por cento na TS (P<0,001). Concluiu-se que o retorno à sensibilidade nervosa deve demorar mais a ocorrer após a TS, devido à maior distância entre cotos. A maior proporção de tecido nervoso sugere que essa técnica favorece a regeneração nervosa.

The post-operative healed tissues in horses submitted to two digital neurectomy techniques, the guilhotine (GT) and the stripping (ST), were evaluated by macroscopy and microscopy. Fourteen months after surgery, 32 samples of scar tissue were collected from four mares that had the members experimentally submitted to both surgical techniques. By macroscopy, the dimensions of the scar tissue of the proximal stump and the distance between nerve stumps were taken. By microscopy, the proportion of nervous tissues in the scar tissue was quantified by histomorphometry. There were no differences between the scar tissue dimensions, but the distance between stumps was 5.6-fold greater in ST subjects. Histologically, connective tissue, macrophages, and thin nervous fibers were observed in scar tissue present in animals of both groups. Nodular structures composed by nervous fascicules were visualized in 56.2 percent (9/16) of the samples collected from the ST group. The mean percentage of the nervous tissue in scar tissue was 0.31 percent in GT samples and 2.6 percent in ST samples (P<0.001). After ST, a longer time to the return of the sensibility may occur due to the greater distance between stumps. However, greater proportion of nervous tissue in the scar tissue suggests that the use of this technique favors nervous regeneration.

significance of the neurovascular structures passing through the spinoglenoid notch

To define the detailed anatomy of the neurovascular bundle at the spinoglenoid notch and to report the dimensions of these structures in cadavers. In the present study, the external diameters of suprascapular artery, vein and nerve were measured at the spinoglenoid notch region in 18 formalin fixed cadavers [36 shoulders] by using a caliper. The study was carried out in the dissection laboratory of Anatomy Departments of Hacettepe University, Ankara University, Ankara and Mersin University, Mersin, Turkey, between 2002 and 2003. The average external diameter for the suprascapular vein was 2.6 mm, artery was 2.2 mm and nerve was 2.2 mm. The spinoglenoid notch was roofed by the spinoglenoid ligament and appeared as a fibroosseous foramen in all cadavers. We found that the vascular structures [suprascapular artery and vein] occupied 68.5% and the suprascapular nerve occupied 31.5% of this foramen. Although the diameters of the vascular structures at the spinoglenoid notch measured by magnetic resonance imaging have been reported, to our knowledge, external diameters of these structures at the spinoglenoid notch have not been described in cadavers. We believe that detailed anatomy of suprascapular neurovascular bundle at the spinoglenoid notch should be appreciated for better understanding of risk factors possibly causing the suprascapular nerve entrapment syndrome, specially for those who are involved in violent overhead sports activities such as volleyball and baseball

Desarrollo del virus de la encefalitis equina venezolana en el tejido nervioso de ratones recién nacidos: ultraestructura e histoquímica / Ultrastructural and histochemical: study on the development of venezuelan equine encephalitis virus in the central nervous system of newborn mice

Se estudio la estructura del tejido nervioso de ratones recién nacidos inoculados con el virus de la EEV. Las células gliales mostraron hichamiento y aumento del glucógeno; las neuronas presentaron alteraciones en la estructura de las mitocondrias y en la organización de los ribosomas; el complejo de Golgi presentó gran desarrollo y tortuosidad de sus cisternas. La actividad de fosfatasa ácida en la cisterna perinuclear y en el retículoendoplasmático granular, sugiere un aumento de producción de esta enzima en las neuronas invadidas por el virus de la EEV. Se estudió la localización de las partículas virales en relación con la viremia y diseminación de la infección, destacándose la presencia de partículas virales en la luz de los vasos sanguíneos y alrededor de las vainas de mielina de algunos axones. El desarrollo de las partículas virales se comparó con las observaciones hechas en otras arbovirosis, proponiéndose que los precursores virales se originen en masas de viroplasma, desde donde migran a través del citoplasma, hacia las cisternas y vacuolas del complejo de Golgi o hacia la membrana plasmática, transformándose en partículas virales maduras por gemación