Substratum preferences of motor and sensory neurons in postnatal and adult rats.
After peripheral nerve injuries, damaged axons can regenerate but functional recovery is limited by the specific reinnervation of targets. In this study we evaluated if motor and sensory neurites have a substrate preference for laminin and fibronectin in postnatal and adult stages. In postnatal dorsal root ganglia (DRG) explants, sensory neurons extended longer neurites on collagen matrices enriched with laminin (~50%) or fibronectin (~35%), whereas motoneurons extended longer neurites (~100%) in organotypic spinal cord slices embedded in fibronectin-enriched matrix. An increased percentage of parvalbumin-positive neurites (presumptive proprioceptive) vs. neurofilament-positive neurites was also found in DRG in fibronectin-enriched matrix. To test if the different preference of neurons for extracellular matrix components was maintained in vivo, these matrices were used to fill a chitosan guide to repair a 6-mm gap in the sciatic nerve of adult rats. However, the number of regenerating motor and sensory neurons after 1 month was similar between groups. Moreover, none of the retrotraced sensory neurons in DRG was positive for parvalbumin, suggesting that presumptive proprioceptive neurons had poor regenerative capabilities compared with other peripheral neurons. Using real-time PCR we evaluated the expression of α5β1 (receptor for fibronectin) and α7β1 integrin (receptor for laminin) in spinal cord and DRG 2 days after injury. Postnatal animals showed a higher increase of α5β1 integrin, whereas both integrins were similarly expressed in adult neurons. Therefore, we conclude that motor and sensory axons have a different substrate preference at early postnatal stages but this difference is lost in the adult.
Institute of Neurosciences, Department of Cell Biology, Physiology, Immunology, Universitat Autònoma de Barcelona, CIBERNED, E-08193, Bellaterra, Spain.
Francisco
F
Gonzalez-Perez
Institute of Neurosciences, Department of Cell Biology, Physiology, Immunology, Universitat Autònoma de Barcelona, CIBERNED, E-08193, Bellaterra, Spain.
Albert
A
Alé
Institute of Neurosciences, Department of Cell Biology, Physiology, Immunology, Universitat Autònoma de Barcelona, CIBERNED, E-08193, Bellaterra, Spain.
Daniel
D
Santos
Medovent GmbH, Mainz, Germany.
Christina
C
Barwig
Medovent GmbH, Mainz, Germany.
Thomas
T
Freier
Institute of Neurosciences, Department of Cell Biology, Physiology, Immunology, Universitat Autònoma de Barcelona, CIBERNED, E-08193, Bellaterra, Spain.
Xavier
X
Navarro
Institute of Neurosciences, Department of Cell Biology, Physiology, Immunology, Universitat Autònoma de Barcelona, CIBERNED, E-08193, Bellaterra, Spain.
Esther
E
Udina
D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D048271:Chitosan / Q000494:pharmacology; D003094:Collagen / Q000494:pharmacology*; D005260:Female; D005727:Ganglia, Spinal / Q000166:cytology / Q000254:growth & development; D039001:Integrin alpha Chains / Q000235:genetics / Q000378:metabolism; D039081:Integrin alpha5beta1 / Q000235:genetics / Q000378:metabolism; D007797:Laminin / Q000494:pharmacology*; D009046:Motor Neurons / Q000166:cytology / Q000187:drug effects*; D009416:Nerve Regeneration / Q000187:drug effects; D016501:Neurites / Q000187:drug effects; D055495:Neurogenesis / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011984:Sensory Receptor Cells / Q000166:cytology / Q000187:drug effects*; D054457:Tissue Scaffolds / Q000737:chemistry
D015703:Antigens, CD; D039001:Integrin alpha Chains; D039081:Integrin alpha5beta1; D007797:Laminin; C085725:integrin alpha7; D003094:Collagen; D048271:Chitosan
chitosan; extracellular matrix; neurite outgrowth; peripheral nerve; regeneration