Local administration of interleukin-1 increases sensory neuron regeneration in vivo.

The proximal and distal stumps of severed mouse sciatic nerves were inserted into opposite ends of polyethylene tubes. The tubes were implanted either empty or filled with collagen alone or in combination with interleukin-1 (IL1). Six weeks later, neurons in the L3-L5 dorsal root ganglia were back-filled with HRP. The number of HRP reactive sensory neurons detected in the IL1-treated animals was significantly greater than that seen in the other experimental groups. Thus, exogenous IL1 may partially mimic the effects obtained with in vivo administration of nerve growth factor in protecting sensory neurons from lesion-induced death.