Tubulization with chitosan guides for the repair of long gap peripheral nerve injury in the rat

Abstract

Running title: Chitosan guides for nerve repair 2 Tubulization with chitosan guides for the repair of long gap peripheral nerve injury in the rat. ABSTRACTBiosynthetic guides can be an alternative to nerve grafts for reconstructing severely injured peripheral nerves. The aim of this study was to evaluate the regenerative capability of chitosan tubes to bridge critical nerve gaps (15 mm long) in the rat sciatic nerve compared with silicone tubes and nerve autografts. Twenty-eight Wistar Hannover rats were randomly distributed into four groups (n=7 each) in which the nerve was repaied by: silicone tube (SIL), chitosan guides of low (~2%, DAI) and medium (~5%, DAII) degree of acetylation, and autograft (AG). Electrophysiological and algesimetry tests were performed serially along 4 month follow-up, and histomorphometric analysis was performed at the end of the study.Both groups with chitosan tubes showed similar degree of functional recovery, and similar number of myelinated nerve fibers at mid tube after 4 months of implantation. The results with chitosan tubes were significantly better compared to SIL tubes (P < 0.01), but lower than with AG (P < 0.01). In contrast to AG, in which all the rats had effective regeneration and target reinnervation, chitosan tubes from DAI and DAII achieved 43% and 57% success respectively, whereas regeneration failed in all the animals repaired with silicone tubes. This study suggests that chitosan guides are promising conduits to construct artificial nerve grafts.

Comparative study between standard and inside-out vein graft techniques on sciatic nerve repair of rats. Muscular and functional analysis

“…Although this technique has a favorable result, it presents as main negative factors: the limitation of calibers, lengths and areas of donor nerves and secondary morbidity [6][7][8] . In this sense, the tubulization technique has been shown to be an appropriate and alternative method in clinical practice, which consists of the fixation of a tubular segment, which may be of biological or synthetic origin, between the stumps of the injured nerve, providing direction and favorable environment to regeneration 9,10 .…”

“…Although this technique has a favorable result, it presents as main negative factors: the limitation of calibers, lengths and areas of donor nerves and secondary morbidity [6][7][8] . In this sense, the tubulization technique has been shown to be an appropriate and alternative method in clinical practice, which consists of the fixation of a tubular segment, which may be of biological or synthetic origin, between the stumps of the injured nerve, providing direction and favorable environment to regeneration 9,10 .Several authors defend the use of venous grafts in the repair of peripheral nerve gaps, justified by the ease of access without damage to the patient, abundance of calibers and donor sites, besides not presenting a financial cost [11][12][13] .Comparative study between standard and inside-out vein graft techniques on sciatic nerve repair of rats. Muscular and functional analysis Bueno CRS et al Acta Cir Bras.…”

The role of chitin and chitosan in peripheral nerve reconstruction

“…10 Similarly, Gonzalez-Perez et al in their study concluded that a degree of acetylation of chitosan of 5% favored nerve regeneration when compared to a lower degree of acetylation (2%). 11 The study was conducted on rat sciatic nerves with a 15 mm defect. 11 The beneficial effect on nerve regeneration can be enhanced not only by a modification of chitosan properties but also by enriching the neurotubes with certain substances, e.g.…”

“…11 The study was conducted on rat sciatic nerves with a 15 mm defect. 11 The beneficial effect on nerve regeneration can be enhanced not only by a modification of chitosan properties but also by enriching the neurotubes with certain substances, e.g. laminin, growth factors (glial cell line-derived nerve growth factor -GDNF) or cells (bone marrow stem cells -BMSCs).…”

Characterization and Schwann Cell Seeding of up to 15.0 cm Long Spider Silk Nerve Conduits for Reconstruction of Peripheral Nerve Defects

“…Chitosan is a polymer generated from chitin that is reported to enhance peripheral nerve regeneration for distances up to 1.5 cm. Compared to silicone and isografts, chitosan had similar or even superior regeneration potential in peripheral nerve defects [9,10]. Disadvantages include significant inflammatory processes during degradation in vivo [11].…”