The changes of expression of MMP-9 and occludin in brain cortex of rats with diffuse brain injury and the correlation between the changes and brain edema

doi:10.3969/j.issn.1002-7386.2014.04.004

Abstract：Objective To observe the changes of expression of MMP-9 and occludin in brain cortex of rats with diffuse brain injury and the changes of brain edema around injury region .Methods The 160 Sprague-Dawley adult male rats were randomly divided into control group ( n =60) and model group ( n =100).The animal models with diffuse brain injury were established in rats by means of Marmarou ’s method.At 3h,12h,24h,72h and 144h after injury,brain water content was detected by dry wet weight measurement method in both groups ,and the expression levels of MMP-9 and occludin around the injury area were measured by immunohistochemistry and Western Blot .Finally the correlation analysis was performed about these results.Results As compared with that in control group , the brain water content in model group was significantly increased in different time points , and the expression levels of MMP-9 around injury area were obviously increased ( P <0.05), however, the content of occludin was significantly decreased .The changes of brain water content were positively correlated to those of MMP-9 ( P <0.05).However the changes of brain water content were negatively correlated to those of occludin expression levels ( P <0.05),so were between MMP-9 expression and occludin expression .Conclusion After the diffuse traumatic brain injury , the expression levels of MMP-9 in brain cortex around injury area are obviously increased , however ,the expression levels of occluding are significantly decreased , and brain edema appears .The increase of MMP-9 expression levels results in the decrease of occludin expression levels ,as a result,brain edema occurs .