Alignment of collagen and laminin-containing gels improve nerve regeneration within silicone tubes.
OBJECTIVE
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.
Verdú
Enrique
E
Group of Neuroplasticity and Regeneration, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain.
Labrador
Rafael O
RO
Rodríguez
Francisco J
FJ
Ceballos
Dolores
D
Forés
Joaquim
J
Navarro
Xavier
X
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D003094:Collagen / Q000494:pharmacology* / Q000627:therapeutic use; D016326:Extracellular Matrix Proteins / Q000494:pharmacology; D005260:Female; D005782:Gels / Q000627:therapeutic use; D007797:Laminin / Q000494:pharmacology* / Q000627:therapeutic use; D051379:Mice; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000648:ultrastructure; D009416:Nerve Regeneration / Q000187:drug effects* / Q000502:physiology; D019736:Prostheses and Implants / Q000592:standards* / Q000639:trends; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology; D012584:Sciatic Nerve / Q000187:drug effects* / Q000293:injuries / Q000601:surgery; D012828:Silicones / Q000627:therapeutic use; D013314:Stress, Mechanical; D016896:Treatment Outcome
D016326:Extracellular Matrix Proteins; D005782:Gels; D007797:Laminin; D012828:Silicones; D003094:Collagen