Immunoregulation effects of bone marrow-derived mesenchymal stem cells in xenogeneic acellular nerve grafts transplant.

This study evaluated whether bone marrow-derived mesenchymal stem cells (BM-MSCs) combined with xenogeneic acellular nerve grafts (xANGs) would reduce the inflammation reaction of xANGs transplantation. BM-MSCs were extracted, separated, purified, and cultured from the bone marrow of rats. Then BM-MSCs were seeded into 5 mm xANGs as experimental group, while xANGs group was chosen as control. Subcutaneous implantation and nerve grafts transplantation were done in this study. Walking-track tests, electrophysiological tests, H&E staining, and immunostaining of CD4, CD8, and CD68 of subcutaneous implantations, cytokine concentrations of IL-2, IL-10, IFN-γ and TNF-α in lymphocytes supernatants and serum of the two groups were evaluated. Walking-track tests and electrophysiological tests suggested the group of BM-MSCs with xANGs obtained better results than xANGs group (P < 0.05). H&E staining and immunostaining of CD4, CD8, and CD68 of subcutaneous implantations showed there were less inflammatory cells in the group of BM-MSCs when compared with the xANGs group. The cytokine concentrations of IL-2, IFN-γ, and TNF-α in BM-MSCs group were lower than xANGs group in lymphocytes supernatants and serum (P < 0.05). However, IL-10 concentrations in BM-MSCs group were higher than xANGs group (P < 0.05). xANG with BM-MSCs showed better nerve repair function when compared with xANG group. Furthermore, xANG with BM-MSCs showed less inflammatory reaction which might indicate the reason of its better nerve regeneration.