超低温冷冻保存后同种异体神经移植的实验研究

目的　探索大鼠同种异体神经移植的可行性。方法　取Wistar大鼠坐骨神经 ,经超低温冷冻保存后移植于SD大鼠坐骨神经缺损处。分成超低温冷冻同种神经移植组 (A)、新鲜同种神经移植组(B)、及自体神经移植组 (C)。 3组均在术后 3、8、12、16周行大体观察 ,检测形态学、电生理变化及血清IL 2、TNF水平。结果　A、C组的腓肠肌萎缩 ;足无明显畸形 ,趾无缺损、无溃疡。B组的腓肠肌萎缩 ;足部溃疡伴趾部分缺损。A、C组在术后 8周刺激神经移植段近端有动作电位出现 ,B组在术后 12周出现。A组动作电位的波幅较B组高。血清IL 2 ,C组与B组差别有显著性 (P <0 .0 5 ) ,A组与C组比较差别无显著性 (P >0 .0 5 )。光镜下A组空泡变性、炎性细胞浸润少。电镜下见髓鞘厚薄基本相同 ,轴突密度高 ,雪旺细胞发育较完善 ,明显优于B组。结论　超低温冷冻保存能降低同种异体神经的抗原性 ,在不用免疫抑制剂情况下 ,动物用同种异体神经移植是可行的

An experimental study of homologous nerve transplantation after ultra deep cryopreservation

Objective To study the feasibility of homologous nerve transplantation at rats. Methods The sciatic nerve defect at SD rats was bridged by the sciatic nerve from wistar rats after ultra deep cryopreservation. They were divided into 3 groups: ultra deep cryopreservation homologous nerve in group (A), fresh homologous nerve in group (B), and autologous nerve in group(C). The gross appearance, morphological and electrophysilogical changes, and the serum levels of IL 2 and TNF were detected at postoperative week 3,8,12,16 for all 3 groups. Results In group A and C atrophy of gastrocnemius muscle was seen. There were no deformity of toes, no toe loss and ulcer formation. In group B, there was atrophy of gastrocnemius muscle and partial loss of toe and ulceration. Action potential (AP) of the proximal segment of grafted nerve in group A and C appeared at week 8 after operation. In group B, AP did not appear until the twelfth week. The amplitude of AP in group A was higher than that in group B. There was a statistically significant difference in the serum level of IL 2 between group B and C, and no difference between group A and C. In group A, there was less vacuolar degeneration and inflammatory cell infiltration in the axon under optical microscope. Comparable thickness of myelin sheaths in group A was found. The axonal density and perfect development of Schwann cell under electron microscope in group A were superior to those in group B. Conclusions Ultra deep cryopreservation may reduce the homologous nerve antigenecity. Even if without the administration of the immunosuppressive agent, it is still feasible to use the homologous nerve in the animal.