Moreover, cerebral infarct size is reduced in mice deficient in MMP-9 or after treatment with MMP inhibitor; this effect was associated with reduced degradation of the MMP-9 substrate ZO-1 as compared to WT mice (Asahi et al., 2000b, 2001a; Jiang et al., 2001). This evidence concerns the gene MMP9 and cerebral infarction.