1. Tau treatment reduced cerebral infarction volume in rats2. Tau treatment reduced the permeability of BBB in rats3. Tau treatment almost completely abolished gelatinolytic activity in ischemic brain microvessels4. Tau treatment significantly inhibited the increase of MMP-9 activity induced by CI5. Tau treatment significantly inhibited the expression of CD147 protein induced by CI6. Tau blocks tPA-related bleeding by inhibiting CD147 - dependent MMP-9 pathway in ischemic brain endothelial cells after IS. Here, MMP9 is linked to brain infarction.