Scar formation at a site of nerve injury can cause a mechanical barrier to axonal regeneration and lead to the development of multiple axonal sprouts to form a
neuroma. We have investigated the hypothesis that the application of a
scar-preventing agent to a nerve repair site would enhance regeneration of the nerve and reduce
neuroma formation. The left sciatic nerve was exposed under general anaesthesia in 18 adult Sprague-Dawley rats. In 12 animals, the nerve was sectioned and immediately re-approximated using four epineurial
sutures, and in 6 of these animals neutralising
antibodies to
transforming growth factor (TGF)-beta1 and
TGF-beta2 were injected into and around the repair site. The six other animals acted as controls. After 7 weeks, the outcome was assessed by recording compound action potential (CAP) ratios, measuring
collagen levels using
picrosirius red staining, and counting the number of myelinated axons proximal and distal to the repair. After repair alone, the mean percentage of area of staining (PAS) for
collagen within the nerve had significantly increased. However, after repair with the administration of
antibodies, the PAS was not significantly different from that in the
sham controls. After administration of
antibodies, the CAP ratios were significantly smaller than in controls but not after repair alone. In both nerve injury groups, the myelinated fibre counts were significantly increased distal to the injury site, but there was no difference between these two groups. We conclude that administration of
antibodies to
TGF-beta1 and
TGF-beta2 reduced
scar formation at the repair site but did not enhance regeneration of the nerve or reduce the development of multiple axonal sprouts.