Nerve regeneration after local administration of the inhibitor peptide of the TGF-ß1 (P144®)

To determine whether local administration of the inhibitor peptide of the transforming growth factor-β1 (TGF-β1; p144®) at the site of the anastomosis of a peripheral nerve can improve the peripheral nerve regeneration. Sciatic nerves were transected and immediately repaired. Wistar rats (n = 45) were divided into three groups: a control group (group I, n = 15), a vehicle solution group (group II, n = 15), and a p144®-treated group (group III, n = 15); 0.25 ml of a solution containing 2.5 mg of p144® per milliliter of tissucol® was administered at the site of the nerve repair in group III. The animals were sacrificed at 12 weeks. Spinal motor neurons and distal axons were quantified. Electrophysiological studies and walking track analysis (WTA) were performed at the end of the survival period. Immunohistological study for TGF-ß1 around the nerve anastomosis was performed. The statistical comparisons between the mean number of neurons (p = 0.27) and distal axons (p = 0.32) in group I, II, and III showed no statistical differences between groups. However, the amplitude of the electrophysiological studies showed a statistically significant difference between the p144®-treated group III and the control group at 2 months postoperatively (p = 0.016). Moreover, WTA showed no statistically significant differences between groups (p > 0.1) except in the p144® group, which was higher than control group I at 2 months postoperatively (p = 0.019). A significant decrease in global cellularity (p = 0.016) and immunohistological activity for TGF-ß1 (p = 0.012) around the nerve anastomosis was found in the group of animals treated with the inhibitor peptide of TGF-β1. P144® delivered at the site of nerve anastomosis demonstrates a capacity to improve the amplitude of electrophysiological studies and WTA at 2 months postoperatively, which might ensure acceleration of the peripheral nerve regeneration by diminishing the scar tissue around the nerve anastomosis.