Conclusions
This study demonstrates that the transplantation of TUDCA-induced M2 macrophages promotes an anti-neuroinflammatory effect and motor function recovery in SCI. Therefore, we suggest that the transplantation of TUDCA-induced M2 macrophages represents a possible alternative cell therapy for SCI.
Methods
To this end, compared to the granulocyte-macrophage colony-stimulating factor (GM-CSF), we evaluated whether TUDCA effectively differentiates bone marrow-derived macrophages (BMDMs) into M2 macrophages.
Results
The M2 expression markers in the TUDCA-treated BMDM group were increased more than those in the GM-CSF-treated BMDM group. After the SCI and transplantation steps, pro-inflammatory cytokine levels and the mitogen-activated protein kinase (MAPK) pathway were significantly decreased in the TUDCA-induced M2 group more than they were in the GM-CSF-induced M1 group and in the TUDCA group. Moreover, the TUDCA-induced M2 group showed significantly enhanced tissue volumes and improved motor functions compared to the GM-CSF-induced M1 group and the TUDCA group. In addition, biotinylated dextran amine (BDA)-labelled corticospinal tract (CST) axons and neuronal nuclei marker (NeuN) levels were increased in the TUDCA-induced M2 group more than those in the GM-CSF-induced M1 group and the TUDCA group. Conclusions: This study demonstrates that the transplantation of TUDCA-induced M2 macrophages promotes an anti-neuroinflammatory effect and motor function recovery in SCI. Therefore, we suggest that the transplantation of TUDCA-induced M2 macrophages represents a possible alternative cell therapy for SCI.