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[目的]对大鼠一侧后肢的缺血再灌注损伤行不同条件缺血预处理,观察脊髓腰骶膨大处运动神经元超微结构的变化,探讨其保护作用。[方法]通过血管夹暂时阻断大鼠左侧髂总、髂内和髂外动脉,建立大鼠后肢缺血模型。以缺血6 h再灌注2 h和12 h分为A、B两组,预处理方式为缺血10 min血液复流10 min,按无预处理、预处理1次、无时间间隔预处理2、3次,分成A0、A1、A2、A3;B0、B1、B2、B3组。取材腰骶膨大处脊髓灰质前角,光镜及透射电镜下观察不同条件预处理对缺血再灌注损伤中脊髓前角超微结构变化。[结果]组织形态观察结果显示A0组缺血再灌注损伤后神经元细胞减少,核溶解消失,损伤明显,预处理后神经元细胞增多,可见部分细胞核存在;B0组缺血再灌注损伤后神经元细胞大部分坏死溶解,预处理后坏死溶解现象减轻。超微结构观察显示A0和B0组脊髓前角神经元细胞不同程度核周器扩张损伤,出现内质网扩张、大量线粒体空泡以及核膜溶解消失。预处理后损伤程度有所减轻,叠加预处理后损伤进一步减轻。[结论]缺血预处理能减轻大鼠肢体缺血再灌注下脊髓腰骶膨大运动神经元的损伤,对脊髓具有保护作用。反复3次预处理产生的保护作用优于2次预处理及1次预处理。
[Objective] To observe the ultrastructural changes of motor neurons in the lumbo-sacral enlargement of spinal cord after ischemia-reperfusion injury of hind limbs in rats under different conditions of ischemic preconditioning and to explore its protective effect. [Method] The left common iliac, iliac and external iliac arteries were occluded temporarily by vascular clamp to establish the rat hind limb ischemia model. The animals were divided into A and B groups at 6 h and 6 h after reperfusion. The preconditioning method was 10 min reperfusion of blood at 10 min after ischemia. The animals were pre-treated with no pretreatment and pretreated without pretreatment 2 , 3 times, divided into A0, A1, A2, A3; B0, B1, B2, B3 group. The lumbosacral enlargement at the anterior segment of the gray matter was observed under light and transmission electron microscopy. The ultrastructural changes of spinal cord anterior horn during ischemia-reperfusion injury were observed under different conditions. [Results] The results of histomorphology showed that the number of neurons decreased, the nucleolysis disappeared, and the damage was obvious in A0 group. After preconditioning, neuronal cells increased and some nuclei were visible. After the ischemia-reperfusion injury in B0 group, Metaphase cells are mostly necrotic and lysed, and necrosis dissolution is relieved after preconditioning. Ultrastructural observation showed that in the A0 and B0 groups, the dorsal horn neurons in the anterior horn of the spinal cord dilated and injured the perinuclear organs. The endoplasmic reticulum dilation, a large number of mitochondrial vacuoles and the disappearance of the nuclear membrane disappeared. Pretreatment lessened the degree of injury, pretreatment superposition to further reduce the damage. [Conclusion] Ischemic preconditioning can attenuate lumbosacral dorsal motor neuron injury induced by ischemia-reperfusion in the limbs of rats and has a protective effect on the spinal cord. Repeated 3 times pretreatment protection produced better than 2 times pretreatment and 1 time.