Selective regeneration of motor and sensory axons in an experimental peripheral nerve model without endorgans.

We assessed the selectivity of motor and sensory axon regeneration towards the distal motor and sensory nerve segments that were disconnected from endorgans in a rat silicone Y chamber model. The L5 ventral root was used as a pure motor nerve, and the saphenous nerve was used as a sensory nerve. In experiment 1 (n=11), the proximal stump of the L5 ventral root, a 1-cm-long L5 ventral root segment and a saphenous nerve segment were inserted into a silicone Y chamber. In experiment 2 (n=11), the proximal stump of the saphenous nerve, a L5 ventral root segment and a saphenous nerve segment were inserted into a Y chamber. The distance between the nerve stumps was 5 mm. Six weeks later, the number of regenerated myelinated motor and sensory axons was measured and compared in the distal two channels. Motor axons showed no selective regeneration, but sensory axons did.