Mitra Ghasemi - Nervous System Stem Cells Research Center, Semnan University of Medical Sciences, Semnan, Iran
Athar Talebi - Nervous System Stem Cells Research Center, Semnan University of Medical Sciences, Semnan, Iran
Ali Ghanbari - Laboratory of Learning and Memory, Research Center of Physiology, Semnan University of Medical Sciences, Semnan, Iran
Parisa Hayat - Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
Behpour Yousefi - Nervous System Stem Cells Research Center, Semnan University of Medical Sciences, Semnan, Iran
Moslem Mohammadi - Department of Physiology, Molecular and Cell Biology Research Center, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
Mahmood Abedinzade - Medical Biotechnology Research Center, Department of Physiology, School of Paramedicine, Guilan University of Medical Sciences, Rasht, Iran
Nooshin Ahmadirad - Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
Sam Zarbakhsh - Nervous System Stem Cells Research Center, Semnan University of Medical Sciences, Semnan, Iran

Objective(s): Despite the many benefits of mesenchymal stem cell (MSC) transplantation for tissue regeneration, there are some limitations to using them, including the high costs, applying invasive procedures, the possibility of transplant rejection, and cell malignancy. This study aimed to investigate the effect of secretions of bone marrow stromal cells (BMSCs) with the cell-free strategy on damaged sciatic nerve with an emphasis on the role of apoptosis and the expression of myelin protein zero (MPZ) and nerve growth factor (NGF) proteins.Materials and Methods: BMSCs were cultured and a ۲۵-fold concentrated conditioned medium (CM) from the cells was provided. After creating a crush injury in the left sciatic nerve of male rats, BMSCs or CM were injected into the injured site of the nerve. Four weeks later, the expression of MPZ, NGF, Bax, and Bcl-۲ proteins in the sciatic nerve and histological parameters of the sciatic nerve and gastrocnemius muscle were assessed.Results: The results demonstrated that injection of CM decreased apoptosis and increased expression of MPZ and NGF proteins, improving remyelination and regeneration of the sciatic nerve almost as much as the transplantation of the BMSCs themselves compared to the control group.Conclusion: The results suggest that BMSC secretions may improve remyelination and regeneration of damaged sciatic nerve by increasing the expression of MPZ and NGF and decreasing apoptosis.

Apoptosis, Mesenchymal stem cells, Conditioned medium, Myelin protein zero, Nerve growth factor, Sciatic nerve