Figure 1.
Expression and activity of MMP-2 and MMP-9 in isolated brain capillaries. A, Representative immunostaining for MMP-2 (left), MMP-9 (middle), and the negative control (right; overlay of green, blue, and transmitted light channels) in isolated rat brain capillaries. Green represents MMPs. Blue represents nuclei counterstained with DAPI. B, Western blot showing MMP-2 and MMP-9 in liver lysate, liver crude membrane fraction (MF), kidney brush border membrane (BBM), brain lysate, and choroid plexus (CP) lysate. C, Western blot showing MMP-2 and MMP-9 in brain capillary (Cap) lysate and brain capillary crude membrane fraction (Cap MF). D, Total MMP enzyme activity in brain capillaries was measured using the fluorogenic substrate Mca-PLGL-Dpa-AR-NH2. MMP activity was assessed in brain capillary lysate with or without MMP inhibitor (GM6001). MMP activity is given as AFU; data are mean ± SEM (n = 3 independent experiments; pooled tissue from n = 10 rats per experiment). **Significantly lower than control (t(2) = 10.37, p = 0.0092; unpaired t test).