Repair of nerve injury by implanting prostheses obtained from isogenic acellular nerve segments. / Reparación de lesiones en nervios mediante el implante de prótesis obtenidas de segmentos acelulares de nervio isogénico.

INTRODUCTION: When a nerve section with a significant gap occurs, it is necessary to use a prosthesis to suture it. To date an autologous nerve segment graft appears to be the best treatment; but it has several important disadvantages. Our goal is to study the effectiveness of an isogenic acellular nerve prosthesis comparing a simple suture with tubulisation. MATERIAL AND METHOD: Four groups of Wistar rats were used. The animals in Group 0 served as donors of nerve segments to graft. Group 1 received the implant with an end-to-end suture. In group 2, the implant was sutured inside an ɛ-caprolactone tube. Group 3 received it in a polylactic-co-glycolic acid tube. We evaluated the motor function (sciatic index and step test in motion), and the regeneration length by histological study of regeneration, after a maximum of 3 weeks. RESULTS: Regeneration was uneven in the three groups. In all groups, there were implants with regenerated nerve fibres at the maximum studied length (15mm) and others where regeneration was scarce. The mean regeneration length was greater in the direct end-to-end suture group (G1), although the regeneration speed was similar in the three groups. Group 1 showed the highest percentage of regeneration, but the variability of results prevents this difference reaching statistical significance. We found no significant differences between the two groups with polymer tubes. CONCLUSION: For the implantation of isogenic acellular nerve prosthesis, under our experimental conditions, the direct end-to-end suture was more effective than when it isprotected with biopolymer tubes.

Responses of the astroglia in sensory deprived olfactory bulb of developing rats.

The effects of unilateral olfactory deprivation on the glial population during the olfactory bulb development have been studied. The lack of sensory stimulation has been found to be related to an increase in gliofibrillary acid protein (GFAP) in the three layers of the deprived bulbs. This increase is due to the higher number of astrocytes in the deprived bulb, which is much more noticeable in the plexiform layer than in the other two, together with a hypertrophy of the reactive astrocytes resulting in an increase in the number and thickness of their prolongations. Our results demonstrate that sensory olfactory deprivation acts as other noxius agents on the CNS, causing gliosis in the olfactory bulb. This gliosis is revealed by astrocytic hyperplasia and hypertrophy.

[Morphofunctional changes in olfactory bulb after elimination of smell stimuli (I). Morphologic study]. / Alteraciones morfofuncionales en el bulbo olfatorio tras privación de estímulos olorosos (I). Estudio morfológico.

We study the olfactory bulb plasticity by olfactory deprivation in the jerbil (Meriones Unguiculatus). We analyze what effects has the odorous stimuli privation in the first days after the birth on the olfactory bulb. We have found that this stimuli absence reduces the size of the bulb in the discussed side and alters the volumes of some of the bulbars layers. This indicates that the structural development of the nervous system specifies of an integrity of their sensorial afferencies.

[Morphofunctional changes in the olfactory bulb after odor stimuli deprivation (II). Histochemical study]. / Alteraciones morfofuncionales en el bulbo olfatorio tras privación de estímulos olorosos (II). Estudio histoquímico.

By histochemical and immunohistochemical methods we study the effects that has the odorous stimuli privation in the first day after the birth on the activity of the olfactory bulb of the gerbil (Meriones Unguiculatus). This sensory deprivation of stimuli causes drastic reductions in given activities (Tyrosine Hydroxylase) no altering other (DOPA-Decarboxylase). This indicates that the functional ripeness of given enzymatic systems specify of an integrity of their sensorial afferences, while it is not necessary for the normal activity of other enzymes even within the same cell.

[Regeneration of critical injuries of the peripheral nerve with growth factors]. / Regeneración de las lesiones críticas del nervio periférico con factores de crecimiento. Estudio experimental.

INTRODUCTION: This project aims to study the regeneration of non-repairable lesions of peripheral nerve by muscle grafts enhanced with growth factors. MATERIAL AND METHODS: The experiment was carried out in two phases. The first one compared direct suture of a critical defect in the sciatic nerve of ten rats, with the interposition of autologous muscle graft, denatured by heat, in another ten. The second phase compared ten rats with nerve repair using an acellular muscle graft, with injection of 2cc of IGF-1 (10mg/ml mecasermin, Injectable solution) into the acellular graft of another ten. A clinical and functional follow-up was carried out including, ambulation, footprint measurement, and "grasping test". . The animals were sacrificed at 90-100 days, and samples obtained for macro- and microscopic studies with toluidine blue, haematoxylin-eosin and Masson's trichrome staining. RESULTS: The first experiment showed the characteristic findings of nerve tissue in muscle graft level sections. The second was an enhancement of the results: post-surgical clinical improvement, early ambulation, decrease in the rate of pressure ulcers in toes, recovery of the footprint, and increasing the percentage of nerve endings in distal sciatic regeneration (47-62%). CONCLUSIONS: In this study the experimental and clinical possibilities of nerve defect repair by denatured muscle are demonstrated, confirming the suitability of the technique. Furthermore, it confirms our hypothesis with clinical and cellular determinations enriched by the addition of growth factors that promote nerve regeneration.