Zahra Bakhtiary, Rasoul Shahrooz, Rahim Hobbenaghi, Saeed Azizi, Farhad Soltanalinejad, Ali Baradar Khoshfetrat, Saeede Amani

SUMMARY
Objectives. Damage caused by the sciatic nerve transection leads to histopathological changes of related skeletal muscles such as atrophy, necrosis, etc. In this study, these changes and ameliorative effects of using mast cells and mesenchymal stem cells along with collagen gel scaffold at the nerve’s transection site were evaluated.
Methods. For this purpose, 90 male rats (180-200 gm) were randomly placed into 6 groups (n = 15) and each group included 3 time periods (2, 4, and 8 weeks, n = 5). The groups include; 1-control: no surgery, 2-nerve transection (Tr): sciatic nerve transection (at a distance of 8 mm) inside a silicone tube, 3-scaffold (S): using collagen gel, 4, 5 and 6-mast cell (MC), mesenchymal stem cell (MSC) and mast cell along with mesenchymal stem cell (MC+MSC): 3 × 104 for each cell mixed with collagen gel. Animals
euthanized and sampled at weeks 2, 4 and 8 for muscle histomorphometry and histopathological evaluations.
Results. The mean number of mast cells and percentage of sarcoplasmolized fibers in the Tr group increased significantly (p < 0.05) and the MC+MSC group had the lowest average.
Also, the highest percentage of necrotic fibers was observed in the Tr group which decreased in the MC+MSC group. This study showed that all parameters of each group significantly recovered in the eighth week compared to other time periods (p < 0.05).
Conclusions. The simultaneous use of mesenchymal stem cells and mast cells in the denervation place and the duration of time significantly reduced the histopathological changes of the denervated muscle tissue.
KEY WORDS
Histopathology; extensor digitorum longus muscle; mast cells; mesenchymal stem cells; rat.