The relationships between MMP-2.MMP-9 and blood-brain barrier in rats with cerebral ischemia and reperfusion

Objective To investigate the relationships between MMP-2, MMP-9 and blood-brain barrier in rats with cerebral ischemia and reperfusion. Methods 54 healthy male SD rat models with middle cerebral artery occlusion and reperfusion were made by suture method. The expression of MMP-2 and MMP-9 in rat brains over a time course ranging from 3h to 7d after reperfusion was measured by gelatin-containing SDS-PAGE zymography. Brain EB content in rat brains was measured within 7d by formamide extraction method. Results The expression of MMP-9 increased dramatically at 24h and reached the peak at 48h,then decreased at 4d and 7d. MMP-9 activity in 24h and 48h groups showed significant difference compared with all other groups (P0. 05). The expression of MMP-2 began to increase at 48h and peaked at 7d. Significant difference was seen between 3h,24h and 7d (P0. 01). Brain EB content in rats 24h after reperfusion was significantly increased than that of the rats 3h and 7d after reperfusion (P0. 05),but showed no difference with rats 48h after reperfusion (P0. 05). Conclusion There exists dynamic changes of MMP-2 and MMP-9 after cerebral ischemia and reperfusion. Blood-Brain barrier injury was much more likely associated with elevated levels of MMP-9 but not MMP-2.