Affiliations: Group of Neuroplasticity and Regeneration, Department
of Cell Biology, Physiology and Immunology, Universitat Autònoma de
Barcelona, E-08193 Bellaterra, Spain | Neural Repair Unit, Biomedical Research Laboratory,
Faculty of Medicine-San Cristóbal, Universidad de Los Andes, 5001 San
Cristóbal, Venezuela | Hand Unit, Hospital Clínic, University of
Barcelona, Barcelona, Spain
Note: [] a
Abstract: Purpose: Placement of extracellular matrix components has been used
as a mean to enhance axonal growth across nerve long gaps repaired by
tubulization. However, such matrices may impede axonal regeneration depending
on its density and microgeometry. Methods: Silicone tubes were prefilled
with collagen or laminin-containing gels and implanted into a 6 mm gap, a
length considered limiting for regeneration, in the mouse sciatic nerve. Gels
were polymerized prior to implantation either in horizontal position or
subjected to gravitational (in vertical position) or to magnetic forces to
induce longitudinal alignment of the fibrils. Recovery of motor, sensory and
sudomotor functions in the hindpaw was evaluated during 4 months postoperation.
Results: Reinnervation started earlier and achieved slightly higher
levels with aligned collagen gels than with the horizontal gel. For the three
groups repaired with tubes with Matrigel, there was a gradation of the
functional results, reinnervation started earlier and reached higher values in
matrix with magnetically-induced, longitudinal orientation than with the
horizontal gel, whereas gravitational alignment followed an intermediate
evolution. Final morphological evaluation showed more dense residual mass of
collagen than of Matrigel at the center of the regenerate nerves. The number of
myelinated fibers was increased in tubes with alignment compared to horizontal
gels. Conclusions: Alignment of collagen and laminin gels within a
silicone tube increases the success and the quality of regeneration in long
nerve gaps. The laminin gel performed better than the collagen gel under each
condition tested. The combination of an aligned matrix with embedded Schwann
cells should be considered in further steps for the development of an
artificial nerve graft for clinical application.
