The regenerative role of mast cells and mesenchymal stem cells in histopathology of sciatic nerve and tibialis cranialis muscle, following denervation in rats

Abstract

Atrophy of the leg muscles following sciatic nerve transection can lead to the death of myofibers. The aim of this study was to evaluate the process of nerve and muscle regeneration using mast cells and mesenchymal stem cells. In this study, 90 adult male Wistar rats weighing 150-200g were randomly divided into six main groups (n=15) and each group into three subgroups (2, 4 and 8 weeks, n=5). Groups: control; without surgery, transection (Tr); Fixing the two ends of the transected sciatic nerve (8 mm gap) in silicone tube, scaffold (S); Put collagen gel inside the silicone tube, mast cell (MC); Placed 3×104 mast cells mixed with scaffold, mesenchymal stem cell (MSC); Placed 3×104 mesenchymal stem cells mixed with scaffold, and mast cell-mesenchymal stem cell (MC+MSC); 3×104 of each of the mast cell and mesenchymal stem cells along with scaffold. Animals euthanized and sampled at weeks 2, 4 and 8 for muscle and nerve histological and nerve immunohistochemistical evaluations. Histomorphometric evaluation results of tibialis cranialis muscle (TCM) included: diameter of muscle fibers, ratio of the muscle fiber’s nuclei to the fibrocyte nuclei (mn/fn), ratio of the muscle fibers nuclei number to the muscle fiber’s number (mn/mf) and ratio of the blood vessels number to the number of muscle fibers (v/mf) in all treatment groups, especially the MC + MSC group, increased compared to the Tr group but the number of mast cells, the percentage of sarcoplasmolysis and necrosis fibers dramatically decreased. Histomorphometric evaluation results of the nerve in its various parts and immunohistochemistry results also showed improve nerve conduction in all groups, especially the MC + MSC group compared to the Tr group. All results were time dependent and in most cases at 8th week were better the other times. Overall, the results of this study showed that the simultaneous use of MCs and MSCs, especially in the eighth week, accelerated the healing of the sciatic nerve and TCM following reinnervation.