Bone marrow stromal and Schwann cells from adult rats can interact synergistically to aid in peripheral nerve repair even without intercellular contact in vitro.

To better understand the use of Schwann cells (SCs) and bone marrow stromal cells (BMSCs) together for nerve repair, we studied whether interactions between these two cell types by diffusible molecules can enhance their utility. In the present study, a co-culture system was established to allow BMSCs and SCs grow in the same culture medium but without physical contact. Before co-culture, the adult SCs were expanded until confluent. The adult BMSCs were cultured until P10 with CD29 and CD44 positive but CD45 negative. After 4 days in culture, > 80% of the BMSCs in the co-culture system showed both GFAP- and S-100-positive, but < 6% of the BMSCs in control culture system showed both GFAP- and S-100-positive. Meanwhile, 68.76% of the SCs in co-culture system showed S-100-positive, which was > 42.03% of the SCs in control culture system. Furthermore, the in vivo study also confirmed that differentiated BMSCs exert a more beneficial effect on repairing injured sciatic nerve function and axonal regeneration than undifferentiated BMSCs. These results indicate that the two most widely used cell types for promoting peripheral nerve regeneration may interact synergistically to aid their roles in peripheral nerve repair.