Nerve Fiber Regeneration in the Rat Sciatic Nerve After Injury and Administration of Mesenchymal Stem Cells

Experimental studies seeking a means of stimulating regeneration of damaged nerve conductors frequently use mesenchymal stem cells (MSC). The aim of the present work was to study the influence of subperineurial administration of MSC on regenerating fibers in the injured rat sciatic nerve using immunohistochemical detection of peripherin. Suspensions of MSC (5∙104 cells in 5 μl of medium) from Wistar–Kyoto rat bone marrow were transplanted into ligature-damaged (40 sec) sciatic nerves in adult animals. After placing of the ligature, the control group received subperineurial medium (5 μl). Two months after surgery, peripherin-immunopositive regenerating nerve fibers were counted and measured on cross sections passing through the distal segment of the recipient nerve. Morphometric analysis of regenerating fibers in ImageJ (NIH, USA) showed that mean nerve fiber thickness in animals of the experimental group increased significantly compared with controls. Studies of the thickness distribution of nerve fibers in the distal segment of the damaged nerve showed that animals given single MSC transplants had a greater percentage of large-diameter fibers than animals of the control group.