ObjectiveTo explore the relationship of the expression of matrix metalloproteinase-9 (MMP-9) and the infarction area after transient focal cerebral ischemia and reperfusion.MethodsModels of transient focal ischemia of MCA in rats were built by placing an intraluminal suture and the neurologic deficit score, lesion area and MMP-9 expression were analyzed.ResultsThe expression of MMP-9 and the infarction area were positive correlation, but there is no correlation between the neurologic deficit score and the MMP-9 expression.ConclusionAfter cerebral ischemia-reperfusion the MMP-9 expression is upregulated. The study suggests that MMP-9 may be involved in infarction lesion.