超低温冷冻保存的吻合血管异体神经移植实验研究

目的探讨吻合超低温冷冻血管的异体神经移植的可行性.方法杂种雌性犬12只,体重15～20 kg;制备带血管坐骨神经动物模型,分别切取坐骨神经6～10 cm,直径4.5～6.5 mm,滋养血管干长3.5～4.5 cm.经超低温冷冻保存3个月后行异体移植.取杂种雄性犬48只,体重15～20 kg;随机分为4组,每组12只,超低温冷冻吻合血管的异体神经移植组为A组,超低温冷冻不吻合血管的异体神经移植组为B组,新鲜吻合血管的异体神经移植组为C组,新鲜吻合血管的自体神经移植组为D组.于术后1、4和12周(n=4)行大体观察,观察吻合动脉血管的通畅率,取移植神经作组织学检测.术后4周测定白细胞介素2活性及T细胞亚群的变化,术后12周行肌电图检测和形态定量学检查.结果术后12周,A、D组后足趾无溃疡,后肢小腿肌肉萎缩和皮肤痛觉有恢复.B、C组后足均有溃疡,后肢小腿肌肉萎缩和皮肤痛觉未恢复.1、4及12周血管通畅率A、D两组平均为83.3%,显著高于C组的50%(P＜0.05).术后4周白细胞介素2活性及T细胞亚群,C组高于A、B、D组(P＜0.01).术后2周A、D组光镜下见神经移植段有逐渐增多的新生毛细血管和再生神经纤维,单位面积髓鞘数、平均灰度值和单位面积髓鞘密度值均高于B、C组(P＜0.01).术后12周,A、D组动作电位潜伏期短,波幅高,传导速度快,神经修复明显优于B、C组(P＜0.01).结论超低温冷冻保存能降低异体血管神经的抗原性,在未使用免疫抑制剂情况下,吻合血管的异体神经移植是可行的;对于较粗大的神经,其神经修复明显优于不吻合血管的异体神经移植.

AN EXPERIMENTAL STUDY ON HOMOLOGOUS VASCULARIZED NERVE TRANSPLANTATION AFTER ULTRA DEEP CRYOPRESERVATION

Objective To study the feasibility of homologous vascularized nerve transplantation after ultra deep cryopreservation. Methods Vascularized sciatic nerve from 12 female dogs was transplanted after ultra deep cryopreservation. Forty-eight male dogs were divided into 4 groups: ultra deep cryopreservation homologous vascularized nerve (group A), ultra deep cryopreservation homologous nerve (group B), fresh homologous vascularized nerve (group C), and fresh autologous vascularized nerve (group D). The gross appearance, patency rate of artery and morphological transplanted nerve were observed 1, 4 and 12 weeks after transplantation respectively. Immunological analysis was performed using IL-2 assay and T lymphocyte subpopulations assay after 4 weeks. Image pattern analysis and electromyogram were observed after 12 weeks. Results In groups A and D, no toe ulcer occurred, the atrophy of later limb and the sense of pain from skin of calf were restore significantly in the postoperative 12th week. In groups B and C, toe ulcer occurred, the atrophy of later limb and the sense of pain from skin of calf were not restored significantly in the postoperative 12th week. The vessel patency rate of groups A and D was 83.3%, which was significantly higher than that of group C (50%,P<0.05). The changes of IL-2 and Th, Ts in group C were significantly higher than that in groups A,B,D(P<0.01). There were increased vessel and regenerated nerve in transplanted nerve under optical microscope and image pattern analysis in groups A and D. There were shorter latent period of motor evoked potential, greater amplitude of action potenlial and faster motor nerve conducting velocity in groups A and D after 12 weeks. Conclusion The antigenicity of the homologous never and vessel may be reduced significantly by being frozen, and cryopreserved vascularized nerve can transferred successfully without the use of immunosuppressive agents. Vascularized nerve may restore good significantly for the thick nerve.