[en] The object of this research project aims to develop an experimental model for selective preganglionic lesions of the upper trunk of the brachial plexus through repair based on a transfer of the phrenic nerve to the musculocutaneous nerve and to clarify, through a comparative analysis, the differences in the results obtained after the interposition of three different types of nerve grafts in the repair of the injury; At the same time, we seek to achieve a reconstructive option by interpositioning in the lesion the acellular nerve tissue as a structural support for a culture of mesenchymal stem cells from bone marrow. 42 Wistar-Lewis rats underwent a C5-C6 lesion in the right forelimb by excising a 3 mm segment from both roots at the level of the intervertebral foramen, followed by a phrenic nerve transfer to the musculocutaneous nerve associated with the interposition of a three types of nerve graft: control group (autograft), experimental group A (acellular nervous tissue) and experimental group B (acellular nervous tissue + mesenchymal stem cells). The rats were randomly distributed into the groups. Repair with mesenchymal stem cells incorporated into acellular nervous tissue aims to increase the recovery potential of the acellular graft in isolation, trying to match it with the results obtained with the autologous graft. The objective is to achieve a tissue that allows surgical morbidity to be minimized, since it would not make it necessary to 15 sacrifice functional nervous tissue and constitutes an unlimited tissue bank in cases in which there are no donor nerves. After 12 weeks, an electrophysiological record was performed to measure the amplitude and latency of the nerve action potential and the compound motor action potential. Nerve graft was studied by electron microscopy, the biceps muscle by histological analysis and the proximal half of the nerve graft (experimental group B) by fluorescence analysis. Statistically significant reductions were found in latency of the compound motor action potential between control group and both experimental groups and increases in the amplitude of the compound motor action potential between groups control and experimental B, as well as in the thickness of the myelin sheath between control group and both experimental groups and in the area of the myelin sheath between groups control and experimental A (P < 0.05). No statistically significant differences have been found between experimental groups A and B.

[gl] O obxecto deste proxecto de investigación ten como finalidade desenvolver un modelo experimental para lesións preganglionares selectivas do tronco superior do plexo braquial mediante a reparación baseada nunha transferencia do nervio frénico ao nervio musculocutáneo e aclarar, mediante unha análise comparativa, as diferenzas nos resultados obtidos despois da interposición de tres tipos diferentes de enxertos nerviosos na reparación da lesión; Ao mesmo tempo, pretendemos incorporar unha opción de reconstrución interpoñendo na lesión tecido nervioso acelular como soporte estrutural para un cultivo de células troncais mesenquimais da medula ósea. 42 ratas Wistar-Lewis foron sometidas a una lesión nas raíces C5 e C6 no membro anterior dereito por escisión dun segmento de 3 mm de ambas raíces ao nivel do foramen intervertebral, seguido da transferencia do nervio frénico ao nervio musculocutáneo asociado a interposición de tres tipos de enxerto nervioso: grupo control (autoenxerto), grupo experimental A (tecido nervioso acelular) e grupo experimental B (tecido nervioso acelular + células troncais mesenquimais). As ratas distribuíronse aleatoriamente nos grupos. A reparación con células nai mesenquimais incorporadas ao tecido nervioso acelular ten como obxectivo aumentar o potencial de recuperación do enxerto acelular illado, intentando igualalo cos resultados obtidos co enxerto autólogo. O obxectivo é 13 lograr un tecido que permita minimizar a morbilidade cirúrxica, xa que non faría necesario sacrificar o tecido nervioso funcional e constitúa un banco de tecidos ilimitado nos casos en que non hai nervios doadores. Despois de 12 semanas, realizouse un estudo electrofisiolóxico para medir a amplitude e a latencia do potencial de acción nervioso e do potencial de acción motor composto. O enxerto nervioso estudouse mediante microscopía electrónica, o músculo bíceps mediante análise histolóxico e a metade proximal do enxerto nervioso (grupo experimental B) mediante análise de fluorescencia. Atopáronse reducións estatisticamente significativas na latencia do potencial de acción motor composto entre o grupo control e os dous grupos experimentais e aumentos na amplitude do potencial de acción motor composto entre o control e o grupo experimental B, así como no espesor da vaiña de mielina entre os grupos control e os dous grupos experimentais e na área da vaíña de mielina entre os grupos control e experimental A (P < 0.05). Non se atoparon diferenzas estatisticamente significativas entre os grupos experimentais A e B.