Neuron counting and the changes of section size after chronic pressure on cervical spinal cord in rabbit / 中国组织工程研究

ABSTRACT

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.MATERIALSThe 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.