Regeneration Across Cold Preserved Peripheral Nerve Allografts Stored In The Glycerol Of Differert Temparature

Objective : To investigate the regeneration of peripheral nerve allografts stored in the glycerol of different temperature.Methods: 96 male wistar rats, aged more than 2 months, weight 300±20 grams, were randomly divided into 7 groups. Group A and B were the control groups, each included 12 rats; all underwent fresh femoral nerve autograft and allograft transplantation respectively. 24 rats in group G were sacrificed for the 48 femoral nerves, which were randomly divided into 4 groups, 12 nerves in each group, and were stored in glycerol for 3 weeks at 4℃, -50℃, -80℃and -196℃respectively. After 3 weeks storage, 4×12 nerves in each temperature group were randomly transplanted into 4×12 rats in target rats group C, D, E and F respectively. 2 weeks after transplantation, two grafts of transplanted nerves in group A~F were harvested randomly and examined with immunohistochemistry to observe the infiltration of lymphocyte to the grafts and regeneration of sciatic nerve and fiber. 9 and 16 weeks after transplantation, the regeneration of sciatic nerve was examined with histology, electro-physiology and electron microscope.Results: Wallerian degeneration was observed in the proximal and distal ends of all grafts of nerves harvested at 2 weeks post-engraftment; infiltration of T lymphocytes at the grafts in group B was significant, less T lymphocytes were seen in group C, D and E, while no T lymphocytes were seen in group A and F. Collagenoblast proliferation was observed in group B, Schwann cell proliferation in group A and F, while both collagenoblast and Schwann cell proliferation were observed in group C, D and E. 9 and 16 weeks post-engraftment, grafts in group B were severely adhered to the near tissue, adherence in group A and F were light, while group C, D and E came between. Nerve regeneration of group A was the best, and group F came second, the next were group C, D and E, while group B was the worst.Conclusion:1. To decrease the storage tempature can decrease immunogenicity.2. The best storage temparature is -196℃.