Assessment of processed human amniotic membrane as a protective barrier in rat model of sciatic nerve injury

Following nerve injury, scar formation is thought to be a considerable impediment to axonal regeneration at the nerve injury site. Nerve wrapping can protect the regenerating axons, and human amniotic membrane (HAM) derived from human placenta is an effective material for that purpose. The impact of nerve wrapping with HAM on functional recovery after nerve injuries, especially after autograft repair of long gap lesions, has not been comprehensively investigated. In the current study, we investigated whether the application of HAM as a nerve wrap to a 10mm segment of transected and repaired nerve would reduce scar formation and permit better axonal regeneration and/or functional recovery in rats. The outcome was assessed with morphological and functional measures. We found that nerves wrapped with HAM had significantly fewer adhesions and less scar formation than controls. Although the final outcome, both functionally and morphologically, was not significantly improved by wrapping the nerve with HAM, the observed decrease in adhesions and scar formation might help the nerve retain its mobility and thus prevent traction injury and ischemia, which are caused by nerve tethering to the adjacent tissue during the healing process.