家兔骶神经冷冻后损伤和修复过程的超微结构观察

Ultrastructural observation on rabbits sacral nerves in cryo-injury and repairing process

目的 了解冷冻后家兔骶神经损伤及修复过程。方法 选取成年健康家兔 4 6只 ,随机分为 3组 :实验组 2 8只 ,假手术组 14只 ,对照组 4只。实验组家兔暴露骶神经进行冷冻处理 ;假手术组仅暴露骶神经 ,不予冷冻处理 ;对照组不予处理。分别在冷冻后即刻、1、3、7、2 1、4 2和 6 0天将各组家兔处死取材进行透射电镜观察。结果 家兔骶神经冷冻后即出现变性、坏死 ,但雪旺氏细胞基底膜仍保持完整 ,冷冻后 7天在残留基底膜管内出现少量再生轴索 ,2 1天后新生神经纤维已较丰富 ,以无髓神经纤维为多 ,此后形态正常的雪旺氏细胞和神经纤维渐多 ,直至冷冻后 6 0天神经组织恢复正常。结论 家兔骶神经冷冻后即出现变性、坏死 ,冷冻 6

Objective To explore the cryo-injury and repairing process on sacral nerves of the rabbits. Methods Forty-six adult rabbits were randomly divided into three groups, 28 in operation group, 14 in sham group and 4 in control group. In operation group, the sacral nerves were displayed and received frozen with liquid nitrogen, while in sham operation the sacral nerves were displayed only. Specimens were harvested and observed by transmission electron microscope at d0,d1,d3,d7,d21,d42 and d60 after operation. Results Degeneration and necrosis occurred to the sacral nerves immediate after cryo-injury, while the basilar membrane of Schwann cell kept intact. New regenerated axis-cylinder appeared in the basilar membrane at d7 after operation, and accumulated at d21. Initially, unmyelinated nerve fiber took the most part of the nerve tract, which was gradually packing with normal Schwann cell and nerve fiber afterward, and the nerve recovered to normal at d60 after operation. Conclusions Degeneration and necrosis occur in sacral nerves immediately after cryo-injury, and the repair process is almost completed in 60 days after operation.