Figure 2

TNF-α-induced MMP-9 release levels and the expression of TNFR1 and TNFR2 in the BBB cells RBECs, astrocytes and pericytes. A, Representative western blots (top panel) and densitometric analysis (bottom panel) of MMP-9 levels in the culture media. Cells were treated with TNF-α (100 ng/mL) for 24 h. Band intensities were quantified by scanning densitometry and the data are expressed as arbitrary units/mg of protein. Each bar indicates mean ± S.E.M. for three experiments. * P < 0.05 and *** P < 0.001, significantly different from vehicle-treated astrocytes and pericytes, respectively. ^## P < 0.01, significantly different from TNF-α-treated astrocytes. ^### P < 0.001, significantly different from TNF-α-treated RBECs. B, Representative images showing the time-course of TNF-α-induced MMP-9 release from RBECs, astrocytes and pericytes. Cells were treated with TNF-α (100 ng/mL) for 3 - 24 h. MMP-9 levels in the culture media were analyzed by western blot. Levels in the culture media of TNF-α-treated pericytes were used as positive controls for levels in the media of TNF-α-treated RBECs and astrocytes. C, Representative western blots (top panels) and densitometric analysis (bottom panel) of TNFR1 and TNFR2 expression in cell lysates of non-treated RBECs, astrocytes and pericytes. Protein levels of TNFR1 and TNFR2 were normalized to β-actin and the data are expressed as a ratio relative to β-actin. Each bar indicates mean ± S.E.M. for three experiments. * P < 0.05, significantly different from RBECs and astrocytes.