Dynamic changes of matrix metalloproteinases in rats with cerebral ischemia and reperfusion

Objective To investigate the changes of matrix metalloproteinases( MMPs) in rats with focal cerebral ischemia and reperfusion. Methods The expressions of MMP-2 and MMP-9 over a time course ranging from 3 h to 7 d after reperfusion were measured by gelatin-containing SDS-PAGE Zymography. Results No or negligible MMP-9 ( 92 kd ) expression was detected in either the hemisphere of sham surgery rats or in the contralateral hemisphere of MCAO rats. MMP-9 activity appeared at 3 h . The expression of MMP-9 increased at 24 h and 48 h compared with sham groups(P 0. 05 ,P 0. 01) and all other groups (P0.05). MMP-2 (72 kd) activity was detected in both hemispheres of each group. The expression of MMP-2 began to increase at 48 h compared with sham group ( P 0.05) and peaked at 7 d. Significant difference was seen between 3 h, 24 h and 7 d (P0.01). There was no difference among non-ischemic hemispheres of each group (P0.05 ) . Conclusion MMP-2 and MMP-9 activities increase after cerebral ischemia and reperfusion. MMP-9 upregulation may be related to the inflammatory injuries after cerebral ischemia and reperfusion while MMP-2 may be responsible for repair after inflammatory injuries.