Local addition of monosialoganglioside GM1 stimulates peripheral axon regeneration in vivo.

Tubulization repair technique is a useful model to study peripheral nerve regeneration by offering quantifiable parameters to assess the possible effect of exogenously applied substances on nerve repair. In the present study we demonstrated that locally administered GM1 inside a tubular prosthesis at the time of implantation can significantly improve the repair process. The sciatic nerve of 8 male C57BL/6J mice, approximately 3 months old at the time of surgery and divided into two groups of 4 animals each, was transected and the proximal and distal nerve stumps were sutured into a polyethylene tube (PT), 0.76 mm internal diameter (ID), to bridge a nerve gap of 4 mm. The tubes contained 2 microliters of collagen type I (2.4 mg/ml) alone or in combination (1:1 volume ratio) with monosialoganglioside GM1 (10 mg/ml in the final solution). Four additional animals received a PT with 1.14 mm ID filled with 5.5 microliters of collagen/GM1 (at the same ratio and final concentration as above). After 6 weeks the PT with the regenerating nerve cables were processed for total myelinated axon counts with a computer-controlled system. GM1 significantly increased peripheral axon regeneration (3427 +/- 64 myelinated axons for the 0.76-mm PT and 3623 +/- 270 for the 1.14-mm PT, mean +/- SEM) compared to the group receiving collagen alone (2516 +/- 156) and this effect did not depend on tube diameter. This action is possibly due to a stimulating effect of GM1 on neurite outgrowth and sprouting.