Effect of IFN-β on mRNA expression of the systems enzyme/inhibitor in astrocytes.

<p>Primary astrocytes (1×10⁵ cells/ml), incubated in serum-free DMEM, were treated with IFN-β at the indicated concentrations (U/ml) in the presence of LPS (10 µg/ml). The control (CTRL) was represented by non-activated and untreated cells. After 24 h of incubation total cellular RNA was isolated as described in the Methods section and analyzed by RT-PCR, using the primer pairs specific for MMP-2, MMP-9, TIMP-2, TIMP-1, CANP-2, calpastatin and GAPDH. Histograms in A-C, represent the quantitation of target genes, after normalization with GAPDH, from three separate experiments with different cell populations. CTRL mRNA levels were set at 100% and the LPS or IFN-β treatments were represented as percent of control (mean±SD). Values statistically different from positive control (LPS-activated cells) are represented by * (One-way Anova followed by Student – Newman – Keuls post hoc test; *P<0.05; **P<0.005). D, Effect of IFN-β on MMP-9/TIMP-1, MMP-2/TIMP-2 and CANP-2/calpastatin mRNA ratios. The MMP-9/TIMP-1, MMP-2/TIMP-2 and CANP-2/calpastatin mRNA ratios were calculated from the levels of individual genes, expressed as percent of negative control. The histogram represents the mean values ± SD of three separate experiments performed with different cell populations. Statistically significant values different from positive control (LPS-activated astrocytes) are indicated with * (One-way Anova followed by Student – Newman – Keuls post hoc test; *P<0.05; **P<0.005; ***P<0.001).