gms | German Medical Science

Objectives/Interrogation: In the case of large defects, end to end suture is not possible and conduit is not enough to obtain good results, thus the gold standard is the autograft, however this solution presents disadvantages: donor site morbility and longer surgery time. Allograft could be another alternative but nerves from donors frequently cause immunogenic response. Starting from 1980, several authors are looking for the correct way to decellularize nerves preserving both the extracellular matrix and basal lamina to improve nerve regeneration. In Italy, a recent law prohibits to commercialize human tissue for profit, thus the use of marketed human-derived devices is forbidden in the case of nerve injuries that need a graft. The purpose of this study is to find an easy, cost effective, standardized and reliable protocol for the allogeneic nerve decellularization to be stored in a nerve bank.

Methods: From a literature review, we concluded that the best method to eliminate cells and to remove cell debris is the chemical one. This method is able to maintain preserved basal lamina and collagen that are indispensable for nerve regeneration. In our study, we propose two chemical-based protocols for the nerve decellularization: one chemical (TritonX100 + sodium dodecyl sulphate- SDS- detergent) in association to sonication cycles, the other also chemical (phosphate-buffered saline-TBP-detergent) in association to a DNAse. According to these protocols, we decellularized human (median and ulnar) and rat (sciatic) nerves. We processed and evaluated samples by means of histology and electron microscopy compared to commercial decellularized allografts.

Results and Conclusions: The results showed that both of them could remove immunogenic components maintaining the basal lamina to improve nerve regeneration. nerves decellularized with the chemical and sonication protocol showed a good tissue organization with oriented and intact collagen, but still present axons within the extracellular matrix. The best results were obtained by the chemical and DNAse protocol in which a rich matched connective matrix was maintained and no integral axons were present.

The purpose of this study is to identify an accessible method of decellularization that is also cost-effective, standardized and permits to obtain a complete removal of immunogenic elements maintaining an intact basal lamina to help axon regeneration.