Functional recovery following nerve injury and repair by silicon tubulization: Comparison of laminin-fibronectin, dialyzed plasma, collagen gel, and phosphate buffered solution

Purpose: This study was designed to investigate the potential for enhancement of peripheral nerve regeneration by the manipulation of the neural microenvironment with laminin-fibronectin solution (LF), dialyzed plasma (DP), collagen gel (CG), or phosphate buffered saline (PBS) in a silicon tubulization repair model. Method: A rat sciatic nerve model of injury and repair was used to study the effects of exogenous matrix precursors (contained in LF or DP), CG or PBS on nerve regeneration. A total of 50 Sprague-Dawley rats underwent left sciatic nerve transection and repair by silicon tubulization. The silicon tubules were either left empty (E), or filled with solutions of LF, DP, CG, or PBS. Nerve function was assessed preoperatively and then postoperatively, every 10 days for 90 days using sciatic functional indexes (SFI). On postoperative day 90, the sciatic nerves were harvested for histologic analysis and the posterior compartment muscles of each animal were harvested and weighed. Molecular analysis for two proteins associated with neural regeneration was performed on the nerve segments. Results: All five animal groups demonstrated equivalent functional recovery. Comparison of the rate of recovery and mean maximal recovery between each group revealed no statistically significant differences, with P- values ranging from 0.30 to 0.95. Posterior compartment muscle masses were similar in all groups except for LF, whose animals had muscle masses 8-9% lower than CG, PBS, or E (P<0.05). Conclusion: Alteration of the regenerating neural microenvironment with exogenous matrix precursors (LF, DP), CG or PBS failed to improve sciatic functional recovery after nerve transection and silicon tubulization in this model. From this study, we conclude that LF, DP, CG, and PBS do not enhance the rate or degree of recovery of peripheral nerve function across a narrow gap when nerves are repaired by silicon tubulization.