Kennett R P, Gilliatt R W
University Department of Clinical Neurology, Queen Square, London, England.
Muscle Nerve. 1991 Oct;14(10):960-7. doi: 10.1002/mus.880141006.
After immersion of the hind limb of the rabbit, up to the lower thigh, in a waterbath, at 1 degree C for 10 to 14 hours under light anesthesia, there was evidence of persistent nerve damage to the tibial nerve, which varied in severity in different animals. Nerve conduction studies, carried out within 24 hours of removal from the bath, showed that in a proportion of the motor and/or afferent fibers, there was conduction failure between the knee and ankle. This was followed, over the next 48 hours, by distal degeneration of the affected fibers. No persistent conduction block was seen. After distal degeneration had occurred, maximal conduction velocity was mildly reduced, suggesting that the fastest-conducting motor and afferent fibers had been particularly affected. Morphological studies confirmed preferential large myelinated fiber degeneration, the earliest lesions being seen in the leg at the level of the upper calf. Limb edema was not seen after cooling, and there was no histological evidence of muscle necrosis or damage to blood vessels. No abnormalities were seen in 4 control animals after hind limb immersion for 12 hours at temperatures of 30 to 35 degrees C. Possible reasons for the proximal site of myelinated nerve fiber damage during hindlimb cooling are discussed.
在轻度麻醉下，将兔的后肢直至大腿下部浸入1℃的水浴中10至14小时后，有证据表明胫神经存在持续性神经损伤，不同动物的损伤严重程度各异。在从水浴中取出后的24小时内进行的神经传导研究表明，一部分运动和/或传入纤维在膝部和踝部之间存在传导障碍。在接下来的48小时内，受影响的纤维出现远端变性。未见持续性传导阻滞。远端变性发生后，最大传导速度略有降低，提示传导最快的运动和传入纤维受到了特别影响。形态学研究证实有选择性的大髓鞘纤维变性，最早的病变出现在小腿上部水平的腿部。冷却后未见肢体水肿，也没有肌肉坏死或血管损伤的组织学证据。4只对照动物在30至35℃温度下后肢浸入12小时后未见异常。讨论了后肢冷却期间有髓神经纤维近端损伤部位的可能原因。
