Nanofibrous Nerve Conduits with Nerve Growth Factors and Bone Marrow Stromal Cells Pre-Cultured in Bioreactors for Peripheral Nerve Regeneration

Peripheral nerve injury (PNI) was the leading cause of permanent dysfunction in movement and sensation. Synthesized nerve guide conduits (NGCs) with Schwann Cells (SCs) can help peripheral nerve regeneration. However, poor accessibility of SCs and lack of full coverage of seeded cells on NGCs can lead to failure of nerve regeneration across long gaps and full functional recovery. To overcome these limitations, bone marrow stromal cells (BMSCs) and a novel culture method were proposed in the current study. BMSCs were harvested and seeded on a never growth factor (NGF)-loaded PCL nanofibrous NGCs and cultured with a rotary cell culture system (RCCS) before implantation. The NGCs were tested in vitro with PC-12 cells to validate the bioactivity of released NGF and to access its ability to promote neurite extension. Also, the NGCs were tested in vivo with rat sciatic nerve model to exam its potential in bridging the long gap (15 mm segmental defect). The efficacy of the NGCs was investigated based on the results of the functional test, electrophysiology test, muscle atrophy, and histological analysis. The results of in vitro PC-12 cell study confirmed the bioactivity of released NGF and showed a significant increase in the neurite extension with the help of PEG-diamine and BSA. These results showed that the novel loading method could preserve the bioactivity of growth factors and achieve a sustained release in vitro. Besides, the results of the in vivo study exhibited a significant increase with the combination of all additives. These results showed that with the help of NGF and RCCS, the NGCs with the seeded BMSCs could enhance peripheral nerve regeneration across long nerve injury gaps.