New 3D hyaluronan-based scaffold for in vitro reconstruction of the rat sciatic nerve

OBJECTIVE: For peripheral nerve regeneration, three-dimensional distribution and growth of cells within the porous scaffold are of clinical significance. The purpose of this study was to test in vitro a novel hyaluronic acid-based tubular conduit (HYAFF-11 biomaterials: 1 x 10 mm) as a nerve guide. METHODS: Human fibroblasts, RN22 Schwann cell lines, human umbilical vein endothelial cells and primary nerve cells, obtained from neonatal rat sciatic nerve, were harvested and seeded on HYAFF-11 devices. Histologic (hematoxylin-eosin), immunohistochemical (antibodies to S100, CD31 and Von Willebrand factor) and PCR analyses were performed after 7 and 14 days from cell seeding onto biomaterials. MTT-based (thiazolyl blue) and DELFIA cell proliferation kit tests were performed to observe the biocompatibility of the cells cultured within the biomaterial devices. RESULTS: We concluded that the conduits were not cytotoxic and demonstrated that cultured RN22 Schwann cells and rat Schwann cells grow in vitro on new artificial nerve conduits. We thus inferred that the HYAFF-11 conduit was a suitable biomaterial able to support nerve cell growth in vitro and after 14 days of cultivation, remained circular with a round lumen, maintaining the size and shape of its original architecture. Finally, attachment and proliferation of endothelial cells attested to the feasibility of developing a coculture system to promote in vivo integration of a microvascularized nerve substitute. DISCUSSION: HYAFF-11 pre-seeded with Schwann and endothelial cells has the potential to be an alternative to autografting for the repair of long peripheral nerve defects.