Expression Of MMP-9 And TIMP-1 In Retinal Ischemia Reperfusion Injury

Objective To investigate the dynamic changes and significance of matrix metalloproteinases 9(MMP-9) and tissue inhibitors of metalloproteinases 1(TIMP-1) in an experimental retinal ischemia reperfusion (RIR) injury.Methods Sixty SD rats were divided into three groups randomly: normal control group,operated group and sham operated group.Ischemia injury was induced in adult rats by increasing the pressure of the anterior chamber with perfusion of normal saline into anterior chamber.After one hour of ischemia and a varied reperfusion time(0,3,6,12,24,48 and 72hours),the rat eyes were enucleated.The levels of MMP-9 and TIMP-1 and their distribution in retina were confirmed by immunohistochemical technique and analyzed by computer-picture analytic system.Rusults MMP-9 positive expression was rarely detected in the normal control group,sham operated group or RIR Oh specimens,while it increased at RIR 3h,increased markedly at 6h, reached maximal levels at 24h and dropped gradually afterwards. TIMP-1 remained relatively unaltered in various groups .The ratio of MMP-9/TIMP-1 was closed to 1 in the normal control group,sham operated group and RIR Oh specimens,while it increased gradually at RIR 3~24h, reached maximal levels at 24h and then dropped to normal level.Conclusion MMP-9 play an important role in the pathomechanism of RIR injury.The imbalance between MMP-9 and TIMP-1 do great damage to retina.