Peripheral nerve defects are very common in clinical surgery. Freeing nerve, nerve diversions or joint flexion can be used to directly connect the two stumps of nerves by using microsurgical techniques; while for long-segment nerve defects, we require a bridging material to bridge defected nerves. Nerve allograft is the most similar to autologous nerve in structure with rich sources for repair of short-segment nerve defects.
Antigenicity-free nerve allografts which retain the natural three-dimensional structure will become ideal scaffold materials for tissue-engineered nerves. Dr. Shuncai Zhang and colleagues from the First Affiliated Hospital of Liaoning Medical University constructed tissue-engineered nerves with acellular nerve allografts in Sprague- Dawley rats, which were prepared using chemical detergents-enzymatic digestion and mechanical methods, in combination with bone marrow mesenchymal stem cells of Wistar rats cultured in vitro, to repair 15 mm sciatic bone defects in Wistar rats.
In this study, electrophysiological detection results showed that the conduction velocity of regenerated nerve after repair with tissue-engineered nerves was similar to that after autologous nerve grafting. Immunohistochemical staining revealed that motor endplates with acetylcholinesterase-positive nerve fibers were orderly arranged in the middle and superior parts of the gastrocnemius muscle; regenerated nerve tracts and sprouted branches were connected with motor endplates.
The wet weight ratio of the tibialis anterior muscle at the affected contralateral hind limb was similar to the sciatic nerve after repair with autologous nerve grafts. The hind limb motor function at the affected side was significantly improved. These findings, published in the Neural Regeneration Research
(Vol. 8, No. 21, 2013), indicate that acellular nerve allografts combined with bone marrow mesenchymal stem cell bridging could be used for repair of long-segment sciatic nerve defects.