Objective: To construct chemically extracted acellular nerve allograft (CEANA) with Schwann cells (SCs) from different tissues and to compare the effect of repairing peripheral nerve defect.
Methods: Bone marrow mesenchymal stem cells (BMSCs) and adipose-derived stem cells (ADSCs) were isolated and cultured from 3 4-week-old SD mice with weighing 80-120 g. BMSCs and ADSCs were induced to differentiated MSC (dMSC) and differentiated ADSC (dADSC) in vitro. dMSC and dADSC were identified by p75 protein and glial fibrillary acidic protein (GFAP). SCs were isolated and cultured from 10 3-day-old SD mice with weighing 6-8 g. CEANA were made from bilateral sciatic nerves of 20 adult Wistar mice with weighing 200-250 g. Forty adult SD mice were made the model of left sciatic nerve defect (15 mm) and divided into 5 groups (n = 8 per group) according to CEANA with different sources of SCs: autografting (group A), acellular grafting with SCs (5 x 10(5)) (group B), acellular grafting with dMSCs (5 x 10(5)) (group C), acellular grafting with dADSCs (5 x 10(5)) (group D), and acellular grafting alone (group E). Motor and sensory nerve recovery was assessed by Von Frey and tension of the triceps surae muscle testing 12 weeks after operation. Then wet weight recovery ratio of triceps surae muscles was measured and histomorphometric assessment of nerve grafts was evaluated.
Results: BMSCs and ADSCs did not express antigens CD34 and CD45, and expressed antigen CD90. BMSCs and ADSC were differentiated into similar morphous of SCs and confirmed by the detection of SCs-specific cell-surface markers. The mean 50% withdrawal threshold in groups A, B, C, D, and E was (13.8 +/- 2.3), (15.4 +/- 6.5), (16.9 +/- 5.3), (16.3 +/- 3.5), and (20.0 +/- 5.3) g, showing significant difference between group A and group E (P < 0.01). The recovery of tension of the triceps surae muscle in groups A, B, C, D, and E was 87.0% +/- 9.7%, 70.0% +/- 6.6%, 69.0% +/- 6.7%, 65.0% +/- 9.8%, and 45.0% +/- 12.1%, showing significant differences between groups A, B, C, D, and group E (P < 0.05). No inflammatory reaction existed around nerve graft. The histological observation indicated that the number of myelinated nerve fiber and the myelin sheath thickness in group E were significantly smaller than that in groups B, C, and D (P < 0.01). The fiber diameter of group B was significantly bigger than that of groups C and D (P < 0.05)
Conclusion: CEANA supplementing with dADSC has similar repair effect in peripheral nerve defect to supplementing with dMSC or SCs. dADSC, as an ideal seeding cell in nerve tissue engineering, can be benefit for treatment of peripheral nerve injuries.