Up-regulation of MMP-13 by IL-1Ra siRNA.

<p>(A) MMP-13 mRNA expression in IL-1Ra and control siRNA-transfected cells. The cells were cultured for 1, 3, 6, 12, and 24 hours, and then mRNA levels were determined using real-time PCR. Values represent fold changes. Differences among groups were analyzed using the Student’s <i>t</i>-test. Data are expressed as the mean ± SD (n = 6). **<i>p <</i> 0.01 vs each time point control. (B) Western blot of MMP-13 (60 kDa) in cells transfected with either IL-1Ra or control siRNAs. Data are representative of three independent experiments. (C) Activity of the endogenous active form of MMP-13 was measured by a SensoLyte® Plus 520 MMP-13 assay. Differences among groups were analyzed using the Student’s <i>t</i>-test. Data are expressed as the mean ± SD (n = 3). **<i>p</i> < 0.01 vs control.