The Influenced Of Expressions Of Mmp-9and Aqp-4by High-dose Methylprednisolone In Traumatic Brain Edema

Objective:To study the relationship between the expressions of MMP-9and AQP-4and to explore the mechanisms of influenced by methylprednisolone in traumatic brain edema. To discuss the possible therapeutic mechanism of treatment with methylprednisolone (MP) for traumatic brain edema.Methods:Fifty-five healthy adult male SD rats were randomly divided into sham operation group (n=5), model group (n=25) and the methylprednisolone treatment group (n=25). The traumatic brain injury of the latter two groups were induced by Feeney’s Methylprednisolone treatment group underwent abdomen injection of methylprednisolone after the injury. Model group underwent abdomen injection of NS of the same amount. In false operation group the rats were given skull operation, but not given hitting by dropping hammer; The rats in the model group and the MP group were divided into5subgroups (6h,24h、3d、5d、7d groups) of5rats each respectively according to different execute time. Under10%cholralhydrate anesthesia, the group of model group and MP treatment group was killed by decapitation. The histology was detected by HE staining, the expression of MMP-9and AQP4was detected by immunohistochemical.Results:The expression of MMP-9and AQP4in the Model group and methylprednisolone treatment group appeared6hours after injury and their expression reached peak on day3. The expression was significantly lower in methylprednisolone treatment group than that in model group (P<0.05). There was a significantly positive correlation between AQP-4expression and expression of MMP-9。(r=0.689P<0.01)Conclusion:1. The expression of MMP-9correlated with AQP4expression positively.2. High-dose of methylprednisolone to treat traumatic brain edema in rats probably by inhibiting the activities of MMP-9and AQP4.