Nanofibrous Nerve Conduits with Pre-seeded Bone Marrow Stromal Cells and Cultured by Bioreactor for Enhancing Peripheral Nerve Regeneration

Abstract

Peripheral nerve injury (PNI) remains one of the most common causes of disability or loss of sensations. Schwann cells (SCs) seeded synthetic nerve conduits have been widely studied for treating PNI. However, this approach is limited by poor accessibility of SCs and lack of dominance by seeded cells. In this study, a novel polycaprolactone (PCL)-based nerve conduit was seeded with bone marrow stromal cells (BMSCs), and the cells were differentiated into Schwann cell-like cells (BMSC-SCs) as a replacement for SCs. The influences of initial cell seeding density on cell proliferation were evaluated. A rotary cell culture system (RCCS) was adopted to dynamically culture the BMSCs seeded on PCL nerve conduits to further improve cell proliferation, differentiation, and neurite extension. The initial cell seeding density of 1 × 105 cells per conduit resulted in the highest proliferation of BMSCs on the PCL nerve conduits. Based on the results of MTS and RT-qPCR, substantial improvements in the proliferation and differentiation of BMSCs were achieved by culturing the BMSCs pre-seeded on PCL nerve conduits in RCCS at the rotating speed of 16 rpm. The neurite outgrowth from PC12 cells was significantly enhanced on nerve conduits pre-seeded with BMSCs and pre-cultured in RCCS. This study demonstrated that dynamic culturing condition provided a better environment for the proliferation and differentiation of BMSCs on novel PCL nerve conduits than that of the static culturing condition. The combination of PCL nerve conduit, BMSCs, and dynamic culture in RCCS could be potentially used as an alternative solution to treat PNI. Peripheral nerve injury (PNI) is one of the leading cause of disabilities. Therapeutic strategies involving cell transplantation showed great promise from previous studies. However, the lack of a reliable cell source and poor culture condition compromise the healing outcome. In this study, a novel polymer-based nerve conduit was seeded with bone marrow stromal cells (BMSCs) and cultured with a rotary cell culture system (RCCS). The influences of initial cell seeding density and the rotating speed of RCCS were investigated. The results indicated that the proliferation and differentiation of BMSCs on nerve conduits were significantly increased in the RCCS with the rotating speed of 16 rpm. The neurite outgrowth from PC12 cells was significantly enhanced on the nerve conduits pre-seeded with BMSCs and pre-cultured in RCCS. This new strategy could potentially be a promising treatment for PNI. In the future, the nerve conduits could be further modified by incorporation of extracellular matrix proteins and growth factors. Moreover, the in vivo animal studies are needed for evaluating the efficacy of the nerve conduits for the treatment of PNI.