Human amnion tissue injected with human umbilical cord mesenchymal stem cells repairs damaged sciatic nerves in rats★

Human umbilical cord mesenchymal stem cells, incorporated into an amnion carrier tubes, were assessed for nerve regeneration potential in a rat nerve defect model. Damaged nerves were exposed to human amnion carriers containing either human umbilical cord mesenchymal stem cell (cell transplantation group) or saline (control group). At 8, 12, 16 and 20 weeks after cell implantation, the sciatic functional index was higher in the cell transplantation group compared with the control group. Furthermore, electrophysiological examination showed that threshold stimulus and maximum stimulus intensity gradually decreased while compound action potential amplitude gradually increased. Hematoxylin-eosin staining showed that regenerating nerve fibers were arranged in nerve tracts in the cell transplantation group and connective tissue between nerve tracts and amnion tissue reduced over time. Gastrocnemius muscle cell diameter, wet weight and restoration ratio were increased. These data indicate that transplanted human umbilical cord mesenchymal stem cells, using the amnion tube connection method, promote restoration of damaged sciatic nerves in rats.