Study The Expression Of Caspase-3 While Methylprednisolone Pre-intervene Ischemia-reperfusion Injury Of Spinal Cord

Background and ObjectiveSpinal cord neyrons are sensitive to ischemia and hypoxia extremely,it is necessary to reperfusion for preventing their death after ischemia,but in recent years we have found a phenomenon that spinal cord had been injured when it.It is still a world puzzle for medicine to protect and restore nerve function after spinal cord ischemia.In the past few decades,we can not solve it thoroughly after researcher's effort at home and abroad,but we have made some progress.Spinal cord ischemia incorporate primary and secondary.It has prove that spinal cord ischemia-reperfusion injury is caused by apoptosis.Apoptosis is a natural physiological process.It can balance human system organization by removeing dead cells and metabolites.The most important point is that this progress has not inflammatory reaction.Research has shown cell is a secondary apoptosis the death of neurons and neuroglial in spinal cord ischemia-reperfusion injury.Apoptosis is a complex pathophysiological process,it is completed by proteinase cascade reaction which mediated by caspase family members.Caspase-3 is considered the key enzyme the earlier biochemical and the activation of indicator the process of apoptosis. Caspase-3 belonged to the family of cystine-Aspartil Acid,which play a central role in the phage of performing apoptosis.It can cut and activate caspase-6,caspase-7,caspase-9.Study confirmed,apoptosis that after injury of central nervous sysrem is mediated by caspase-3,but,the research on express of caspase-3 by the time and the influence of MP has been report rarely.Research has shown that,it can releve spinal cord injury and improve the function of nerve if the secondary injury of spinal cord is intervened by drug.It has been admitted in the world that high-dose MP can therapy acute spinal cord injury.MP is the only drug for treating the spinal cord injury by U.S FDA.Study has shown that it can protect nerve cells of spinal by inhibiting the up-regulation of caspase-3.After the study of the third acute spinal-cord injury by US,the standard treatment has been widely used around the world. However, SCⅡis very common in clinic.Such as sever cervical spinal disease,thoracic spinal,stenosis,they can lead to SCⅡafter decompression surgery.If we can prove the character of the express of caspase-3 by the time and the inflation of MP,it will be a very big step for spinal disease.This research will observe the express of caspase-3 by making the modle of SCⅡof rats and the inflution of MP after 6h,1d,3d,7d of the spinal cord,to study the inhibition of caspase-3 in apoptosis.Methods1 Animal model and grouping:120 healthy,purebred adult male SD rats (from experimental animal center of zhengzhou university) were randomly divided into three groups:Group A(mormal group)40 rats,GroupB(SCⅡ)40 rats,GroupC(MP group)40 rats. SCⅡcan be established by clamping the abdominal aorta between the left and right renal artery for 30 minutes,and then relaxing 3h.Group C is given MP(the dose is 30mg/kg).before spinal cord ischemia,which is diluted to 0.5 ml with physiological saline and injected tail vein of rats.,D and E, normal group,SCⅡgroup,MP treatment groups (three different doses).2 Animal in each group are anesthetized in 6h,1d,3d,7d.Open the chest,Insert venous cannula from the left ventricle,inject physiological saline quickly,douche until bright liquid,reperfusion 4 percent of paraformaldehyde until the animal died.Bite spinous of T11,T12,L1 and take spinal cord away from the cone about one centimeter,regulary dehyde fixed,dehydration,paraffin-embedded,microtome section,stain HE and immunohistochemistry.3 Immunohistostaining and image analysis:Immunohistostain sections and use image analysis system to measure absorbance of the caspase-3 positive coloring substance. select six different point of view randomly in each section,compute the average absorbance value of A with computer in 400 high magnification.A response to staining intensity representing the relative content of caspase-3.4 Statiscal analysis:use with statistical analysis software of experimental data.All data denotes mean plus or minus standard (α=0.05) is the size of test.use single factor analysis of variance(ANOVA) analyze overall difference among three groups.Results1 After SCⅡ,injury of rats has obvious edema,degeneration,necrosis and other pathological changes.2 In normal group spinal cord,the express of caspase-3 is weakly positive,while in SCⅡgroup,the express of caspase-3 increased significantly.3 If using MP before SCⅡ,it can releve shows weakly secondary spinal cord injury and the express of caspase-3 decreased significantly positive.4 Difference was statistically significant among three groups on the express of caspase-3 (P<0.05); There was significant statistical difference between group B and group A(P<0.05). NO significant statistical difference was found in the expression between group A and group C (P>0.05). There was significant statistical difference between group B and group C (P<0.05).Conclucions1 Using MP can improve pathological form of spinal cord injury before ischemia-reperfusion injury.It indicates that MP can protect injured spinal cord.2 In normal spinal cord nerve cells,the express of caspase-3 is weakly positive,while in SCⅡ,its express increased significantly and its express decrease significantly before spinal cord injury.3 After three days of SCⅡ,the express caspase-3 is highest in spinal nerve cells then decrease gradually,and decrease significantly in seveth day.