The Sustaining Compressive Impact On Internal Structure Of Spinal Cord Injury

Objective:To investigate the impact on internal structure of spinal cord caused by sustained compression,Methods:45 healthy New Zealand rabbits were Selected to establish the traumatic model of abdominal side compression on spinal cord and randomly classified into 4 groups as followings:GroupⅠof mild compression trauma (n=12);GroupⅡof moderate compression trauma(n=12);GroupⅢof serious compression trauma(n=12);GroupⅣof comparison group(no trauma after spinal cord exposed,n=9) compressions were introduced into groupⅠ-Ⅲwith the duration of 1h(A),2h(B),4h(C) respectively,among which 3 rabbits were sampled instantly, and the behaviour change of the other 1 had been observed in a week after operation. Spinal cord was sampled and sliced up continuously with HE dying adopted,The changes in internal structure and pathological signs were observed,The C-los,Nitric oxidesynthase(NOS),immune-histologi-chemical dying was applied to observe positive cells numbers of C-fos,NOS in the gray matter plies of groups,and the results were compared with the faked operation group,Results:1,The general morphological and pathological changes after the compressive trauma in the abdominal sides:In Group 1,the compressed area in the abdominal sides was slightly concave with minor khaki color,The gray matter and white matter maintain the structural integrity and central canal was also integrated,ependyma cells were arranged trimly,there was no or only spotty hemorrhage occasionally visible in anterior horn of spinal cord and no obvious changes of neurocyte can be observed,In Group 2,liquid necrosis and malacias took place in the compressed area in the abdominal sides of spinal cord,The structure of the gray and white matter were loose,the shape of central canal was changed as a result of compression,The following signs could be observed:the focal hemorrhage,the swelling of anterior horn cells,the infiltration of monocytes and multi-nucleiu inflammatory cytes, the emergence of scattered hemorrhage and small amount of empty bubbles in white matter,the exudation and edema under the spinal pia matter,In Group3,serious liquid necrosis and brown malacias were seen in the compressed area in the abdominal and dorsal sides of spinal cord,The curd matter could be seen effluent in some samples,The following signs could be observed under microscope:the structures of the gray and white matter were dispersive,the central canal was shrinking and even disappeared in some cases,the proliferated ependyma cells,The displacement,pieces of necrosis and injury were observed in gray matter with inflammatory reaction accelerated,White matter bled along with the formation of huge amount empty bubbles,some of which were reticular in shape with inhomogeneous distribution of fibers and vague presence of neurogila cells. Congestion,hemorrhage and edema under the spinal pia matter were observed,Blood flew into the opposite site of compression through the gap of spinal pia matter.The shape of spinal cord were slightly recovered in first 3 groups in a week after compression,as well as nerve fibers of white matter,There was no obvious difference in the injury degree of the cross-sectional gray matter,The hyperplasia of neurogila cells was visible,2.the expression of c-FOS and NOS was low in the area of anterior horn of gray matter in faked operation group with opposite results in the rest three groups,The differences of expression of c-FOS and NOS between the first 3 group and Group 4 were statistically significant(P＜0.05),3.the animal euthology:the double back legs inⅠ,Ⅱ,Ⅲgroups have grading recovery to certain extent,exacerbated along with the increase of the compression intensity and duration,Conclusion:1.there was a positive correlation between the changes of internal construction and various symptoms after compression on the abdominal side of spinal cord,2.The internal construction and the function of nerve could be recovered after withdraw of the compression and the recovery degree was decided by the degree and duration of compression.3.The expressions of NOS and C-FOS after compression on the abdominal side of spinal cord were correlated with the site of compressing.