Biology Reference
In-Depth Information
altering axon number and morphology (
Lauto et al., 2007, 2008
).
A photocrosslinkable hydrogel based on chitosan has been
in vitro
success-
fully characterized and proposed as a new adhesive for peripheral nerve anas-
tomosis (
Rickett et al., 2011
).
Chitosan has further been used in combination with other biomaterials
for bridging peripheral nerve gaps (
Fan et al., 2008; Gu et al., 2012; Jiao
et al., 2009; Lin et al., 2008; Liu et al., 2011; Simoes et al., 2010; Wang
et al., 2005; Xie et al., 2005; Xie et al., 2008; Xu et al., 2009
). Chitosan-
polylactid acid (PLA) composite nerve conduits showed good biocompati-
bility and permeability, good mechanical strength, intensity, and elasticity,
facilitating microsuture manipulation, and they provide enough mechanical
strength to support nerve regeneration. Chitosan-PLA conduits promoted
axonal regeneration of rat sciatic nerves across a defect of 10 mm, with com-
parable success to nerve autografts, resulting in muscle reinnervation
12 weeks postsurgery (
Xie et al., 2008
).
Yet, tubular grafts made out of chitosan membranes have been success-
fully used to improve peripheral nerve functional recovery after neurotmesis
of the rat sciatic nerve, and they induced better nerve regeneration and func-
tional recovery when compared with poly-lactic-polyglycolic acid (PLGA)
control tubes (
Simoes et al., 2010
).
A dual component artificial nerve conduit consisting of an outer
chitosan microporous conduit and an internal oriented PGA filament
matrix has been used to bridge a 10-mm defect in rats after long-term delay
(3 or 6 months), resulting in reinnervation of the atrophic denervated mus-
cle by regenerating neurites through new muscle-nerve connections (
Jiao
et al., 2009
). The same conduit has been used to regenerate 30-mm beagle
dog sciatic nerve defects, resulting in reconstruction and restoration of
nerve continuity and functional recovery as indicated by improved loco-
motion activities of the operated limb after target muscle reinnervation
(
Wang et al., 2005
).
Finally, a couple of clinical studies in which chitosan scaffolds have been
used to repair peripheral nerve have been reported. Chitosan/PGA artifi-
cial conduits have been successfully used in repairing a 35-mm-long
median nerve defect of a human patient. During the 3-year follow-up
period, an ongoing motor and sensory functional recovery
postimplantation was detected (
Fan et al., 2008
). Chitosan/PGA conduits
have further been used to repair a 30-mm long median nerve defect in the
right distal forearm of a 55-year-old male patient. Thirty-six months after
the surgery, reproducible compound muscle action potentials have been
