Collagen- and laminin-containing gels impede peripheral nerve regeneration through semipermeable nerve guidance channels.

Semipermeable guidance channels were filled with saline, collagen-, or laminin-containing gels and used to repair a 4-mm sciatic nerve gap in mice. After 12 weeks, nerve cables regenerated in gel-filled channels displayed fewer myelinated axons than saline-filled channels. Remnants of the exogenous substrates were still in evidence, in amounts related to the initial collagen or laminin gel concentration. The impairment of nerve regeneration by collagen or laminin-containing gels suggests that the regenerative environment created within semipermeable channels is not improved by the addition of growth substrates in a gel form.