Immunological study of a chitosan prosthesis in the sciatic nerve regeneration of the axotomized dog.

This study demonstrated that when the regeneration of the axotomized sciatic nerve is induced through tubulization with chitosan, this biomaterial does not induce immunostimulation or immunodepression in the dog. Canine females were distributed among three groups: an intact control group which was only isolated, an axotomized control group, and an axotomized group which was tubulized with 3% chitosan prostheses. In vitro culture and phagocytosis tests, as well as IgG and IgM serum concentrations, were determined in peripheral blood on days 0, 15, 30 and 60. The results showed that chitosan implants did not importantly affect the immune response.

[Regeneration of the axotomised sciatic nerve in dogs using the tubulisation technique with Chitosan biomaterial preloaded with progesterone]. / Regeneracion del nervio ciatico axotomizado del perro mediante la técnica de tubulizacion con el biomaterial quitosana precargado con progesterona.

INTRODUCTION: Injuries to peripheral nerves can have different causes and may lead to disorders affecting mobility, sensitivity and loss of motor function as they progress. Weiss, in 1944, introduced tubulisation to promote the regeneration of a sectioned nerve. In this study the biomaterial Chitosan was used to induce and stimulate the regeneration of the sciatic nerve in dogs. At the same time, we took advantage of the characteristics offered by Chitosan to include the neurosteroid progesterone in its matrix, as a promoter of axonal growth. AIMS. The aim of our study was to determine the degree of regeneration of the sciatic nerve in dogs when axotomised tubulised with a Chitosan prosthesis steeped in the neurosteroid progesterone. MATERIALS AND METHODS: Young adult female dogs were used to evaluate the regeneration of the sciatic nerve induced at a standard of 15 mm; regeneration was determined by means of an axonal growth chamber. Nerve growth was studied through histological analysis and by electron microscope. RESULTS: The statistical analysis showed that there were no significant differences in the number of myelinated fibres between the experimental groups. The electron microscope images of the transmission in the regenerated nerves in the groups that were tubulised with Chitosan, with and without neurosteroid preloading, revealed an advanced regenerative process. This was evidenced by the fact that collagen fibres, elastin, Schwann cells and both myelinated and non myelinated fibres were observed in all cases. CONCLUSIONS: The regeneration of axotomised, tubulised nerves was achieved regardless of the treatment that was applied. The distal nerve segment that was analysed revealed a similar structure to that of a normal nerve.

Regeneración del nervio ciático axotomizado del perro mediante la técnica de tubulización con el biomaterial quitosana precargado con progesterona / Regeneration of the axotomixed sciatic nerve in dogs using the tubulisation technique with chitosan biomaterial preloaded with progesterone

Introducción. Los nervios periféricos se pueden lesionar por distintas causas, y causar en el curso de su evolución trastornos de movilidad, sensibilidad y pérdida de la función motora. Weiss, en 1944, introdujo la tubulización para promover la regeneración de un nervio seccionado. En este estudio se utilizó el biomaterial quitosana para inducir y estimular la regeneración del nervio ciático del perro, además de aprovechar la cualidad que presenta la quitosana para incluir en su matriz el neuroesteroide progesterona, como un promotor de crecimiento axónico. Objetivo. Determinar el grado de regeneración del nervio ciático del perro axotomizado-tubulizado con una prótesis de quitosana impregnada del neuroesteroide progesterona. Material y métodos. Se emplearon perros hembra adultos jóvenes para evaluar la regeneración del nervio ciático inducida a un defecto de 15 mm, y se determinó su regeneración a través de la cámara de crecimiento axónico. Los crecimientos nerviosos se estudiaron mediante un análisis histológico y por microscopía electrónica. Resultados. El análisis estadístico indicó que no hubo diferencias significativas en el número de fibras mielinizadas entre los grupos experimentales. La microscopía electrónica de transmisión de los nervios regenerados de los grupos tubulizados con quitosana, con y sin neuroesteroide precargado, indicaron un proceso regenerativo avanzado, puesto que en todos se apreciaron fibras de colágeno, elastina, células de Schwann y fibras mielinizadas y no mielinizadas. Conclusiones. La regeneración de los nervios axotomizados y tubulizados se logró con independencia del tratamiento aplicado. El segmento nervioso distal que se analizó evidenció una estructura similar a la de un nervio normal (AU)