兔颈脊髓慢性受压后神经元计数及截面积的变化

背景机械压迫可造成神经细胞死亡,直接的机械性损伤和复杂的病理生理学机制都可导致轴突和神经元胞体的病变.目的观察兔颈脊髓慢性压迫后神经细胞超微结构变化、压迫程度与神经细胞损害的关系.设计以实验动物为研究对象,随机对照观察性研究.材料实验于2002-12/2003-08在广西中医学院附属瑞康医院中心实验室完成.雄性新西兰大白兔共48只,体质量(2.45±0.28)kg.分为空白组,轻、重度压迫组,每组16只.方法建立兔颈脊髓慢性受压轻、重度动物模型,空白组为伪手术.分别进行颈脊髓光镜、电镜观察、神经细胞凋亡检测(TUNEL法),计算神经元个数,神经元截面积. 主要观察指标主要结局各组光镜观察结果.次要结局①各组电镜观察结果.②神经细胞凋亡检测.结果兔颈脊髓慢性受压后出现神经元萎缩、脱失,神经元截面积减少,压迫后有神经元、神经细胞凋亡现象,空白组神经元形态正常,数量多,为(40±2)个,神经元截面积(41.24±15 61)μm2;轻度压迫组神经元(27±2)个,神经元截面积(20.82±6.57)μm2;重度压迫组神经元(22±2)个,神经元截面积(17.96±9.03)μm2.轻、重度压迫组与空白组比较差异有显著性意义(P＜0.01),轻、重度压迫组间比较差异无显著性意义(P＞0.05).慢性压迫后神经细胞超微结构发生胞核体积减少,核仁不清,粗面内质网减少.髓鞘板层结构松散,出现泡解现象,轴浆内细胞器减少或缺失等变化.结论脊髓慢性受压后神经细胞超微结构发生变化,压迫程度越重,神经细胞损害越重,脊髓慢性压迫存在细胞凋亡现象.

Neuron counting and the changes of section size after chronic pressure on cervical spinal cord in rabbit

BACKGROUND: Mechanic pressure could cause neurocyte death. Both direct mechanic injury and complex pathophysiological mechanism can induce the pathological changes of axon and neuronal soma. OBJECTIVE: To observe the relationship between ultrastructural changes and pressure degree of neurocyte and neurocyte damage. DESIGN: A randomized controlled observational study using experimental animals as study subjects.MATERIALS: The study was conducted in the Central Laboratory of Ruikang Hospital affiliated to Guangxi Traditional Chinese Medical University from December 2002 to August 2003.SUBJECTS: Fourty-eight male New Zealand rabbits with a bodymass of (2.45 ± 0. 28) kg were randomly divided into control group, mild pressure group and severe pressure group with 16 rabbits in each group.METHODS: Animal models with mild and severe cervical spinal cord chronic pressure were established in rabbits. Control group was pseudo-operation group. Spinal cord observation under optical microscope and electron microscope, neurocyte apoptosis analysis (TUNEL method), neuron counting, and the section size of the neuron were analyzed respectively.MAIN OUTCOME MEASURES: Main results: observational results under optical microscope of each group. Subordinate results: ① observational results under electron microscope of each group; ② neurocyte apoptosis analysis RESULTS: After chronic pressure in the spinal cord of rabbits, phenomena like neuron atrophy,loss,reduced section size,and neuron and neurocyte apoptosis appeared. The morphology of neurons in control group was normal and the quantity was quite a lot, which was (40 ± 2), and the neuron section size was(41.24 ± 15.61) μm2.The number of neuron of mild pressurc group was(27 ± 2), and the neuron section size was(20. 82 ± 6.57) μm2. The number of neurons of severe pressure group was (22± 2), and the neuron section size was( 17. 96 ± 9.03 ) μm2. The difference between mild, severe pressure group and control group was significant( P ＜ 0.01),while the difference between mild and severe pressure groups was insignificant(P ＞ 0. 05 ). The ultrastructural changes of neurons after chronic pressure were reduced volume of soma, unclear nucleolus and reduced rough endoplasmic reticulum. The lamellar structure of spinal sheath was loose with vacuole, and the cell organs in axial plasma were reduced or lost.CONCLUSION: The ultrastructure of neurocyte changes after chronic pressure in spinal cord. The more serious the pressure is, the more serious the neurocyte damages are. Cell apoptosis exists after chronic pressure in spinal cord.