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Introduction: As a reliable alternative to autografts, decellularized peripheral nerve allografts (DPNAs) maintain the complex natural structure of native nerves minimizing the immune response. However, there is currently a lack of decellularization methods for peripheral nerve that remove cells minimizing any adverse effect in extracellular matrix (ECM) that overcoming the autograft results. The aim of this study was to evaluate the in vivo regeneration potential of a novel chemical-enzymatic decellularization method (CE) for peripheral nerves in comparison with the decellularized classical control group Sondell (SD) and the autograft technique (AUTO).
Methods: Sciatic nerves from Wistar rats were decellularized by the new CE method [distilled water, 3% Triton X-100, 1% SDS, 4% SDC and enzymatic mix (RNase and DNase)] and with SD method (1). Afterwards, they were used to repair a 10-mm sciatic nerve gap and compared to autograft technique (1) and native nerves as control group (CTR). After 15-weeks the nerve tissue regeneration was evaluated by using histological (HE, MCOLL and immunohistochemistry) and histomorphometrical methods.
Results: Histologically, hematoxylin-eosin (HE) showed an active regeneration process in all operated animals, being more dispersed in decellularized groups in comparison with AUTO group. MCOLL histochemical method showed a higher degree of myelinization in AUTO and CE groups as compared to SD group. In addition, MCOLL revealed signs of fibrotic response around the regenerated tissue in SD group. Nerve regeneration was confirmed by the positive immunoreaction for Schwann cells (S-100) and regenerated axons (neurofilament (NFL)) in all groups. However, overall regeneration was more organized in AUTO group followed by CE groups and finally SD. Histomorphometrical analysis showed that the new decellularized nerves obtained with CE protocol presented significant superior density and total number fiber results (p< 0.05) than the classic SD group. Moreover, CE group showed comparable histomorphometrical results than the AUTO group (p>0.05). As expected histomorphometrical values were not comparable to those observed in healthy nerves.
Discussion & conclusion: This in vivo histological study revealed promising results with the use of the novel decellularized allografts obtained with CE method. The CE method resulted in a superior regeneration histological profile than the classical method of SD. These results were comparable, but not superior, to the gold standard AUTO group. Finally, more studies are still needed to determine the efficacy of these new products in the treatment of long nerve gaps at the histological, molecular and functional levels.
Fundings: Supported by the Spanish “Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica, Ministerio de Economía y Competitividad (Instituto de Salud Carlos III)”, Grant No FIS PI20-0318 co-financed by the “Fondo Europeo de Desarrollo Regional ERDF-FEDER European Union”; Grant No P18-RT-5059 by “Plan Andaluz de Investigación, Desarrollo e Innovación (PAIDI 2020), Consejería de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucía, España”; and Grant A-CTS-498-UGR18 by “Programa Operativo FEDER Andalucía 2014–2020, Universidad de Granada, Junta de Andalucía, España”, co-financed by the ERDF-FEDER, the European Union.
References:
- Chato-Astrain, J. et al., J Tissue Eng Regen Med. 14, 789, (2020)
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