局部低温程度与大鼠脊髓缺血损伤保护的相关性

背景脊髓的局部低温保护减轻了创伤性脊髓损伤后的二次损伤,但是低温深度与保护程度是否具有相关性目前尚不清楚. 目的研究局部低温的程度与大鼠脊髓缺血损伤保护的相关性. 设计完全随机对照实验. 地点和对象实验在中国医科大学普外三科实验室完成,采用雄性 Wistar大鼠. 干预模拟制作大鼠脊髓缺血动物模型,对 L5～ L10行逆行蛛网膜下腔低温生理盐水灌注,控制脊髓核心温度在 38℃, 34℃, 30℃, 18℃ 4个水平,近端动脉压控制在 5.3～ 6.6 kPa,阻断时间分别为 12, 16 min. 主要观察指标观察动物截瘫数及截瘫指数并作组织学检查. 结果实验动物的截瘫数及截瘫指数随着温度的降低而降低. 38℃, 34℃, 30℃, 18℃各组阻断 12 min后,截瘫数分别为 6, 3, 0, 0;阻断 16 min后分别为 8, 6, 5, 0.截瘫指数 0- 4评定结果为,阻断 12 min, 38℃分别为 2, 1, 2, 3, 0; 34℃分别为 4, 1, 2, 1, 0; 30℃和 18℃ 8只截瘫指数均为 0;阻断 16 min, 38℃分别为 0, 0, 1, 4, 3只; 34℃分别为 2, 1, 3, 2, 0只; 30℃分别为 4, 2, 2, 0, 0只; 18℃ 8只截瘫指数均为 0.组织学检查显示随着温度降低,脊髓缺血损伤逐渐减轻. 结论与轻、中度低温相比,深度低温对脊髓缺血损伤的保护作用更显著,局部低温的深度与大鼠脊髓缺血损伤保护程度呈正相关.

Level of local hypothermia and its extent of protection to spinal ischemic injury in rats

BACKGROUND:Local hypothermia of the spinal cord protects against and lessens the secondary injury after the traumatic injury to the spinal cord, but whether the level of local hypothermia correlates with its extent of protection is still unclear.OBJECTIVE:To study the correlation between the extent of protection and the level of hypothermia in spinal ischemic injury in rats. DESIGN:Totally randomized controlled trials.SETTING AND SUBJECTS:This experiment was conducted at the Laboratory of the Third Division of General Surgery of China Medical University(CMU).Male Wistar rats were used in the trials.INTERVENTIONS:The spinal ischemic model of rats was prepared, and hyperthermic saline was perfused to the L5- L10 of subarachnoid cavity.The temperature of the spinal cord was maintained at four levels:38 ℃, 34 ℃, 30 ℃ and 18 ℃ ,and the proximal artery blood pressure was kept between 5.3 kPa to 6.6 kPa.The blockage time was 12 min and 16 min respectively.MAIN OUTCOME MEASURES:The number of rats with paraplegia,the index of paraplegia and histological observations.RESULTS:The number of rats with paraplegia and the index of paraplegia decreased following the decreasing temperature.The number of rats with paraplegia was 6,3,0 and 0 respectively for groups of 38 ℃, 34 ℃, 30 ℃ and 18 ℃ after blockage was applied 12 min,and the number of rats with paraplegia was 8,6,5 and 0 after blockage was applied for 16 min. The index of paraplegia was 2,1,2,3 and 0 after it was blocked for 12 min in 38 ℃ group and 4,1,2,1 and 0 in 34 ℃ group. However, in group of 30 ℃ and 18℃ ,the index of paraplegia was 0;the index of paraplegia was 0, 0,1 and 4 after it was blocked for 16 min in 38 ℃ group,2,1,3 and 0 in 34 ℃ group and 4,2,2,0 and 0 in 30 ℃ group; however, the index of paraplegia was 0 in 18℃ group. The histological examination showed that with the lowering temperature, the spinal ischemic injury was lessened.CONCLUSION:Compared with light and moderate hypothermia, deep hypothermia has a more apparent protection against the spinal ischemic injury, and there is a positive correlation between the level of local hypothermia and its extent of protection against the spinal ischemic injury.