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Background and Purpose spinal cord neurons are extremely sensitive to ischemia and hypoxia, immediately after ischemic injury regain blood reperfusion necessary measures to prevent its death, but in recent years, only to find that the role of some kind of damage factor, spinal cord after a certain time ischemia, has been the blood reperfusion it was an obvious dysfunction, even irreversible spinal cord delayed neuronal death, a phenomenon known as the spinal cord ischemia-reperfusion injury. Protection and recovery of function after spinal cord injury for the medical profession is still a major global problem, in the past few decades, the majority of scientists at home and abroad through tireless efforts, although not completely overcome it, but has also made some progress. Spinal cord injury, including primary and secondary, the first has proved to apoptosis in spinal cord ischemia reperfusion damage cell death. Apoptosis is a the inherent natural physiological process to maintain the stability of the human system organizations, by clearing dead cells and metabolites, and this process is not accompanied by local inflammation is its greatest feature, research has shown, whether it is human or animal , spinal cord ischemia-reperfusion injury of neurons and glial cell death are secondary result of apoptosis. Apoptosis is a complex pathological physiological processes, primarily mediated by members of the Caspase family proteases cascade completion of the reaction, wherein Caspase-3 is considered to be a key enzyme of the process of apoptosis, activation of caspase-3 of apoptosis Early biochemical indicators, Caspase-3 is the cystine - aspartic protease family, plays a central role in the apoptotic execution phase. Caspase-3 can cut and activation of Caspase-6, Caspase-7, Caspase-9. The study confirmed that Caspase-3 mediated guide apoptosis in the central nervous system after injury, but over time, Caspase-3 expression and change features of methylprednisolone their impact fresh reports. Studies have shown that reduce spinal cord injury and improve neurological function can play the role of high-dose methylprednisolone treatment of acute spinal cord injury has been recognized in the international drug intervention in spinal cord injury lesion. The methylprednisolone (MethylprednisoloneMP) are approved by the FDA only for the treatment of spinal cord injury drugs. Studies have shown that it can play a role in the protection of the spinal cord nerve cells through inhibition of Caspase-3 expression amount raised. Through the United States National Acute Spinal Cord Injury Study, the standard treatment has been widely used in all over the world with acute spinal cord injury. Clinical spinal cord injury (spinal cord ischemic reperfusion injury SCII) is very common, such as severe cervical myelopathy, thoracic spinal stenosis surgical decompression can lead to spinal cord ischemia-reperfusion injury after ischemia-reperfusion. If animal experiments proved the expression of Caspase-3 in the above disease surgery time-varying characteristics and MP on the expression will be a very big step forward for the treatment of spinal disorders. The subject through the production of rat spinal cord ischemia reperfusion injury in animal models, observation of spinal cord injury after 6h, 1d, 3d, 7d in Caspase-3 expression levels and methylprednisolone pre-intervention affect its expression, to study spinal cord ischemia Caspase-3 on the inhibition of apoptosis after reperfusion injury. Materials and methods Animal Model of and packet Health purebred adult male SD rats (Experimental Animal Center of Zhengzhou University) 120, the quality 200 ± 20g. Randomly divided into three groups: group A (normal group) 40 rats; B group of 40 rats of (SC group II), C group (MP group) 40 rats. The abdominal aorta between the left and right renal artery occlusion 30 min of reperfusion 3 hours make SC II model; C group before spinal cord ischemia 30 minutes to give MP dose of 30mg/kg, diluted with saline to 0.5 ml from rat tail vein injection, group B is given the same dose of saline. Specimens drawn from each group of experimental animals, respectively, 6h, 1d, 3d, 7d when anesthesia, the chest was opened, IV cannula is inserted from the left ventricle, rapid infusion of normal saline flush to the effluent liquid was clear, reperfusion mass percentage of 4% POM, until the death of the animal bite than the T11, T12, L1 spinous process and lamina, starting from the tapered rounded up to the spinal cord of approximately 1cm routine formalin-fixed, dehydrated, embedded in paraffin, HE staining and immunohistochemical staining. 3 immunohistochemical staining and image analysis slice immunohistochemical staining image analysis system to measure Caspase-3 positive staining substances absorbance of each piece randomly selected from six different point of view, 400 high magnification using a computer to calculate the mean absorbance value A A staining intensity of the reaction, represents Caspase-3 relative content. 4. Statistical analysis SPSS16.0 statistical analysis software processing of the experimental data, all data are expressed as mean plus or minus standard deviation (x ± s), press the alpha = 0.05 significance level, using single-factor analysis of variance (ANOVA) three groups the overall differences between the use of LSD-t test was used to compare group differences between any two P lt; 0.05 was considered statistically significant. 1 rat spinal cord ischemia-reperfusion injury, the injury edema, degeneration, necrosis and other pathological changes. Caspase-3 expression in the spinal cord was weakly positive. Normal group, ischemia-reperfusion group spinal cord nerve cells Caspase-3 expression was significantly increased. Ischemia-reperfusion injury group before using the MP mitigate secondary injury to the spinal cord, Caspase-3's expression was significantly weakened, shown as weakly positive. Caspase-3 the expression level of the three groups between overall difference was statistically significant (P lt; 0.05), group A with group B, the difference was statistically significant (P lt; 0.05) in group B and C group difference was statistically significant (P lt; 0.05), and no significant difference between group A and group C (P gt; 0.05). Conclusion 1. Before ischemia-reperfusion injury prophylactic use of MP can significantly improve the pathological spinal cord injury, indicates that the spinal cord ischemia-reperfusion injury earlier MP a protective effect on spinal cord injury. Normal nerve cells in the spinal cord of Caspase-3 expression was weakly positive rat spinal cord ischemia-reperfusion injury in the spinal cord nerve cells significantly up-regulated the expression of Caspase-3, using the MP before the spinal cord injury in rat spinal cord can cells of Caspase-3 expression was significantly reduced. Spinal cord ischemia-reperfusion injury after the first three days of spinal cord nerve cells within the highest expression level of Caspase-3, and then gradually reduced, significantly reduced on day 7.
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