Efficacy of Freeze-thawed Peripheral Nerve Allograft in the Dog

• Project/Area Number: 12833002
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Institution: Iwate University
• Principal Investigator: TOMIZAWA Nobuyuki Iwate University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (00217530)
• Project Period (FY): 2000 – 2002
• Project Status: Completed (Fiscal Year 2002)
• Budget Amount: ¥3,400,000 (Direct Cost: ¥3,400,000); Fiscal Year 2002: ¥1,100,000 (Direct Cost: ¥1,100,000); Fiscal Year 2001: ¥700,000 (Direct Cost: ¥700,000); Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
• Keywords: freeze-thawed nerve allograft / peripheral nerve / Schwann cell / dog / rat / 同種冷凍神経移植

Research Abstract

To obtain the fundamental information firstly, the functional recovery from peripheral nerve defects was studied by carrying out freeze-thawed nerve allograft and autograft of rat sciatic nerves. Although several neurological examinations were performed after nerve grafting, only superficial pain perception was recovered within the 110 days postoperatively in most animals. Sciatic function index was not effective to evaluate the motor nerve function because of individual deviations.
To investigate the efficacy of Schwann cell (SC) transplantation with freeze-thawed peripheral nerve allograft, 4 types of SC cultures from adult rat sciatic nerves were compared. The method by Calderon-Martinez was the most excellent technique on viability and purity of SCs. The same method for culturing SCs was performed in adult beagle dogs. As a result, the purity of SCs was about 90% and the number of SCs was about 3.6×10^7 from 3cm of dog sciatic nerve.
In order to evaluate the application of SC cultures along with freeze-thawed nerve allograft, co-culture of SCs and freeze-thawed nerve grafts, and the direct injection of cultured SCs to freeze-thawed nerve grafts were performed. No living SCs were observed in co-cultured nerve graft. On the other hand, there were many viable SCs in nerve graft by the direct injection of cultured SCs to freeze-thawed nerve grafts.
From the results of this study, it was elucidated that freeze-thawed nerve allograft was effective on the recovery of sensory function, and SC culture from adult rat sciatic nerves was available for promotion of nerve regeneration. Moreover, it was proved that SC culture from adult dogs was also possible, and the direct injection of cultured SCs to nerve grafts was effective for the application of SC cultures along with freeze-thawed nerve allograft.