Effects of Adipose-Derived Mesenchymal Stem Cells and Human Amniotic Membrane on Sciatic Nerve Repair in Rats

 Peripheral nerve injuries remain a great challenge for microsurgery, Despite the significant progress in recent decades. The current gold standard is autogenous nerve grafting with a success rate as low as 50% in long gaps. Current studies have focused on finding alternative methods for bridging nerve defects. Previous data have demonstrated human amniotic membrane role in stimulating neural regeneration. On the other hand, Adipose-derived mesenchymal stem cells can differentiate into all three germ layers and could support nerve repair. The purpose of this study was to compare the role of the human amniotic membrane with and without adipose tissue stem cells in sciatic nerve injury with gap in rats.

 we aimed to compare the role of the human amniotic membrane with and without adipose tissue stem cells in sciatic nerve injury with gap in rats.

Twenty-four male Wistar rats were randomized into four groups. In the first group, the nerve gap was repaired using the inverse resected nerve segment (control group), the second group was repaired with a human amniotic membrane (AM group), the third group repair was done with an amnion sheet with seeded Adipose-derived mesenchymal stem cells (AM/ADMSCs group). The last group wasn't repaired and both stumps were sutured to muscles.

 All the animals underwent the procedures and survived without complication. The sciatic function index and hot plate test result were significantly improved in the AM and AM/ADMSCs group that was comparable to the control group (as a gold standard of care) (P > 0.05). There is no significant difference between experimental groups in latency 12 weeks after surgery. Based on histopathology findings, regenerative nerve fibers were seen in the implanted area of both AM and AM/ADMSCs group; however, the nerve fibers were surrounded with significant fibrosis (scar formation) in AM/ADMSCs group. The axon counts in the control groups were significantly higher than in the other groups (P < 0.01).

Our study showed the role of amniotic membrane in the promotion of nerve regeneration in the sciatic nerve injury with a gap, but adding Adipose-derived mesenchymal stem cells has no extra benefit as well as caused more tissue scar.