The Effect Of High-dose Of Methylprednisolone On C-fos And Heat Shock Protein 70 After Acute Spinal Cord Injury In Rats

ObjectiveRecent several researches suggested that C - fos was one of the mainly immediate - early genes (IEGs ). Several stimulative factors could induce the expression of C - fos increased in central nerve systerm. HSP70 family is one of the heat shock protein families. It is an important internal protective factor of nerve tissues after injury. Nowaday, methylprednisolone is the first choice to cure acute spinal cord injury. High - dose of methylprednisolone can markedly control inflammatory reaction after acute spinal cord injury and decrease the secondary injury. This experiment used immunohistochemistry and image analytical technology to discuss the effect of methylprednisolone on C - fos and heat shock protein 70 after acute spinal cord injury in rats and the mechanism that methylprednisolone cure acute spinal cord injury.Materials and MethodsThis study selects 72 female Wistar rats ( affored by experimental animal center of Chinese Medical University). These rats were randomly assigned to A, B,C,D group, which are correspond to control group (six rats) , sham -operation group ( eighteen rats) , ASCI + NS group (twenty - four rats) , ASCI + MP group (twenty - four rats). The acute spinal cord injury models were made by Allen' s method. The rats in the D group received a first dose of methypred-nisolone (30mg/kg) after 15 min and then received an infusion of methylprednisolone at 5. 4mg/kg per hour for 23 hours. The rats in the C group received an infusion of physiological saline at the same dose and the same time. The rats ofB>CXD groups were sacrificed at lhx3hN6hNld>2dx3d postoperatively. The spinal cord were taken for the study. Three rats of B group were taken in each time. Four rats of CXD groups were taken in each time. Immunohistochemistry S— P method and HE straining were performed. We observed the expression of C- fos and heat shock protein 70 positive reactants in each group 1,3 ,6 hours, 1, 2, and 3 days after injury. Six sheets of tissue slice of every rat were selected. All of images were dealed with Metamorph Image System(V 4.6). The expression of C - fos and HSP70 were measured by integrated optical density average (IOD). Each index was denoted with x ± s. All of data was analyzed by SPSS 10. 0 statistics software. Correlation between two groups was analyzed by Levene s test for equality of variances. Significance test was evaluated by T - test.ResultsPositive expression of C - fos and heat shock protein 70 was found in the spinal cord injury tissues of NS and MP groups. The expression of C - fos increased after acute spinal cord injury. The most expression was in 3 hours. The expression of C — fos in methylprednisolone group 1,3, and 6 hours after injury was less than that in normal saline group with significant difference ( p < 0. 05). There was no obvious difference between the two groups 1,2, and 3 days after injury. The expression of heat shock protein 70 increased after acute spinal cord injury. The most expression was in 1 day. The expression of heat shock protein 70 in methylprednisolone group 6 hours, 1, and 2 days after injury was more than that in normal saline group with significant difference (p < 0. 05,p < 0.01,p < 0.01 ,respectively). There was no obvious difference between the two groups 1,3 hours and 3 days after injury. There were little expression in control and sham - operation groups.Conclusions1. Positive expression of C — fos and heat shock protein 70 was found in the acute spinal cord injury tissue.2. Methylprednisolone can restrain the expression of damagable factor ( C -fos protein) , and promote the expression of protective factor (heat shock protein 70) . Therefore, methylprednisolone can cure acute spinal cord injury.