Protective Effect of the Human Epineural Patch Application after Sciatic Nerve Crush Injury Followed by Nerve Transection and End-to-End Repair

Nerve regeneration under unfavorable wound conditions remains challenging. We introduce the human epineural patch (hEP) as a novel nerve protector for post-trauma applications, comparing its regenerative efficacy with that of the human amniotic membrane (hAM). Following crush injury, transection, and end-to-end repair (CTR), 36 athymic nude rats were randomly assigned to six experimental groups (n = 6 each): control (no-protection), hEP, or hAM application post-repair. Assessments at 6 weeks and 12 weeks included functional evaluation (Toe-Spread and Pinprick tests), gastrocnemius muscle index (GMI), histomorphometric analysis (myelin thickness, axonal density, fiber diameter, percentage of myelinated fibers), and immunofluorescence staining for neurogenic, angiogenic, and immunogenic markers. The hEP group exhibited superior motor (3.167 ± 0.167) and sensory (3.500 ± 0.212) recovery and GMI values (0.955 ± 0.014), compared with the No protection group (p < 0.05). Myelin thickness (3.480 ± 0.019 µm, p < 0.0001), fiber diameter (10.788 ± 0.197 µm, p < 0.05), and myelinated fiber percentage (89.841% ± 0.453%, p < 0.01) were significantly higher in the hEP group. At 12 weeks, hEP application significantly increased the expression of Laminin B (2.083 ± 0.083), nerve growth factor (NGF) (1.750 ± 0.250), and vascular endothelial growth factor (VEGF) (2.667 ± 0.333), corresponding with improved function. The application of hEP at the sciatic nerve repair site after CTR injury significantly enhanced nerve regeneration compared with hAM. This study introduces hEP as a promising alternative nerve protector for traumatic nerve injuries.