Missouri Osteochondral Preservation System for Nerve Preservation of Nerve Isografts Improves Functional Recovery After Peripheral Nerve Reconstruction With Polyethylene Glycol-Mediated Fusion.

Abstract

Functional outcomes after peripheral nerve reconstruction remain suboptimal, particularly for large-gap defects. This study evaluated the combined use of the Missouri Osteochondral Preservation System for nerve (MOPS-N) preservation for nerve isografts and polyethylene glycol-mediated fusion (PEGf) in a rat sciatic nerve gap model. Adult male Lewis rats underwent an 8-mm sciatic nerve gap reconstruction. Animals were randomized to the following 6 groups: (1) MOPS-N isografts stored 28 days + PEGf, (2) MOPS-N isografts stored 56 days + PEGf, (3) Normosol-preserved isografts stored 28 days + PEGf, (4) Normosol-preserved isografts stored 56 days + PEGf, (5) autograft, and (6) autograft + PEGf. Functional outcomes were assessed through sciatic functional index, rotarod performance, and hindlimb grip strength testing over 6 weeks. At end point, gastrocnemius muscle mass ratios were measured, and nerve segments underwent histomorphometric analysis for G-ratio evaluation. MOPS-N groups consistently outperformed Normosol groups and autografts without PEGf. By week 6, both MOPS-N groups achieved significantly higher sciatic function index scores than both autograft groups and Normosol groups. Rotarod times were significantly greater in both MOPS-N groups and autograft + PEG group than Normosol across weeks 3-6. Grip strength recovery approached baseline in both MOPS-N groups and autograft + PEG group by week 4, whereas autografts without PEG and Normosol grafts remained impaired. Muscle mass ratios were highest in MOPS-N groups. Histomorphometric analysis of nerve segments showed MOPS-N groups maintained more uniform G-ratios across segments. MOPS-N-preserved viable nerve isografts combined with PEG-fusion promoted superior functional recovery, muscle reinnervation, and axonal integrity compared with autografts and Normosol preservation. This strategy has potential to address the barrier of limited shelf-life of stored viable peripheral nerve tissue, expanding the translational potential of viable nerve grafts for reconstruction of large-gap peripheral nerve injuries. Additional studies are needed to assess the immunogenicity of MOPS-N-stored allografts.