Comparison of the neurotropic effects of motor and sensory Schwann cells during regeneration of peripheral nerves.

We examined the inductive ability of motor and sensory Schwann cells on regeneration of motor and sensory axons using a silastic Y chamber, and Lewis rats L5 ventral root (motor) and saphenous nerve (sensory). We developed four experimental models: motor-motor nerve group-proximal motor stump with distal fresh and frozen/thawed motor nerve segments (n = 7); sensory-sensory nerve group-proximal sensory stump with distal fresh and frozen/thawed sensory nerve segments (n = 7); motor-sensory nerve group-proximal motor stump with distal fresh and frozen/thawed sensory segments (n = 8); and sensory-motor nerve group-proximal sensory stump with distal fresh and frozen/thawed motor segments (n = 8). The gap was set at 4 mm. Six weeks postoperatively we compared the number of regenerated myelinated axons in the two distal channels, and found that sensory Schwann cells have a strong inductive ability for regeneration of both sensory and motor axons. Motor Schwann cells have weak inductive ability for regeneration of motor axons and no inductive ability for regeneration of sensory axons.