Progesterone-induced transdifferentiation of bone marrow stromal cells into Schwann cells improves sciatic nerve transection outcome in a rat model.

Background: Peripheral nerve injury is a common lesion in clinical practice and transplantation is one of the most common approaches to its treatment. While nerve graft is used for restoring the defected nerve using autologous or allogenic tissues, Schwann cells are considered as an alternative source. In this study, bone marrow stromal cells (BMSCs) were induced to transdifferentiate into Schwann-like cells (SLCs) using progesterone.

Methods: The BMSCs were collected from the long bones of rats and were transdifferentiated in vitro into SLCs by preinduction with β-mercaptoethanol and retinoic acid, followed by induction with bFGF, PDGF, forskelin and progesterone. The SLCs were then transplanted in a rat model of sciatic nerve injury with 1-cm gaps. A sciatic function index (SFI), histological, immunohistochemical and ultrastructural studies were used in evaluating the improvement in the nerves regeneration.

Results: The results show significant differences in the SFI between the control and the treated groups (P<0.05). The transplant was immunoreactive to S100, and the electron microscopy showed myelination in the transplanted cells.

Conclusions: There were functional and structural improvements in the progesterone-induced SLCs, which were not significantly different from the heregulin-treated ones (positive control) but still significantly different from negative controls.