gms | German Medical Science

Objectives/Interrogation: Peripheral nerve injury (PNI) is a common origin of motor and sensory dysfunction and leads to discontinuity of electrical conductivity. Nerve guidance channels are invented for large nerve gaps as alternative implants. New trends have shifted to a more completed and faster nerve regeneration, calling for a thorough investigation into conductive materials. Gold is investigated widely concerning its potential roles in promoting peripheral nerve repair. Bone marrow mesenchymal stem cells (BMSC) are increasingly significant for PNI. They were highly proliferative and capable of promoting sensory and motor system recovery, axon sprouting as well as Schwann cell (SC) proliferation and migration. In this study, we intend to evaluate BMSC and SC loaded gold nanocomposite channels in severe PNI repair.

Methods: We fabricated a polydopamine (PDA) coated gold/polycaprolactone (PCL) nanoscaffold via multilayer molding method. We examined the surface morphology and elastic modulus. We evaluated the proliferative, adhesive and neural differentiation potential of gold nerve channel for BMSCs and SCs in vitro. We established a 15-mm sciatic nerve defect model of Sprague Dawley (SD) rats. We thoroughly investigated the functional, electrophysiological and morphological performances in BMSC loaded gold/PCL conduit, SC loaded gold/PCL conduit, gold/PCL conduit, PCL conduit and autograft.

Results and Conclusions: We fabricated nerve scaffolds via 3D multilayer molding method. A multilayer structure of PDA coated gold/PCL nanocomposite channel increased rigidity of the scaffold wall. Multiporous and multilayer design improved biodegradation because pores and space between layers allowed body fluid to enter the internal channel freely. Macropores permitted oxygen and water exchange for nutrition supply. BMSCs and SCs were cultured on different nanoscaffolds and their proliferation, adhesion and viability were greatly improved by gold nerve channels. In addition, BMSCs were induced into Schwann-like cells on PDA-gold/PCL nanosheets and the neural expression was evaluated in vitro. The supportive ability of two cells were believed to diffuse growth factors, oxygen and other nutrients. We noticed morphological, functional nerve recovery, and angiogenesis at 6, 12 and 18 weeks postoperatively. CD34 expression was significantly higher in gold conduit groups than PCL group. The myelin sheath and axonal regrowth was also markedly elevated by gold nanoparticle application, which was further enhanced using BMSC seeding.