The relationship between matrix metalloproteinase-9 and edema after spinal cord injury

Objective:To investigate the relationship between the early expression of matrix metalloproteinase-9(MMP-9)and spinal edema after actue spinal cord injury.Method:70 rats were randomized into two groups,the sham-operated group and the injuried group.The 10 rats of sham-operated group were performed laminectomy alone.The models of spinal cord injury were introduced with Allen's way by a 10g×2.5cm impact on the posterior T8-T9 spinal cord.Rats were sacrificed at 6h,12h,1d,3d,5d,7d after injury.The water content of injuried spinal cord was measured by dry-wet weight method and the expression of MMP-9 was performed by immunohistochemical staining.Result:The water content of injuried spinal cord increased and reached the maximum at 3-5d.The expression of MMP-9 increased at 6h after spinal cord injury and reached peak in 1-3d.The expression of matrix metalloproteinase-9 wasn't found in the sham-operated group.The data showed that the water content of spinal cord was positively correlated with the level of MMP-9.Conclusion:After acute spinal cord injury,the early spinal edema is related to the level of MMP-9,but the time of their reaching peak isn't absolutely consistent.