Exogenous laminin induces regenerative changes in traumatized sciatic and optic nerve

Laminin is an extracellular matrix component which can promote neuritic elongation in vitro and has been implicated in the promotion of nerve regeneration in vivo. The present study was undertaken to determine if implantation of Elvax pellets containing exogenous laminin distal to site of lesion could promote regenerative responses in vivo in the adult rat peripheral (sciatic) and central (optic) nerve. In peripheral nerve preparations, Elvax pellets containing laminin or collagen were assessed for their ability to "lure" transected axons into 5-mm-long silicone tubes. In optic nerve studies, laminin pellets were inserted distal to site of nerve crush, and the extent of axonal elongation 2.5 mm to the injury site was assessed. Laminin-containing pellets appeared to support appreciable axonal elongation in both systems. This effect was dose-dependent and not exerted by collagen pellets, substrate-free pellets, or pellets containing irradiated laminin. Collagen IV had some beneficial effect in peripheral, but not central, nerve preparations.