FIGURE 8.

SAA-induced expression of sPLA₂ is not mediated by IL-1β. A, rat smooth muscle cells were treated with (SAA) or without (Control) SAA (2 μm) or IL-1β (100 ng/ml) for 24 h in the presence (+) or absence (−) of IL-1Ra (1 μg/ml), at which time total RNA was extracted and analyzed by real time PCR for sPLA₂ mRNA. RNA expression was calculated as described under “Experimental Procedures” and data expressed as RNA levels relative to the control ± S.D. (n = 3). The level of sPLA₂ mRNA in control-treated cells was significantly different from that in SAA- (p < 0.01), IL-1β- (p < 0.01), and SAA plus IL-1Ra-treated cells (p < 0.001). The level of sPLA₂ mRNA in IL-1β-treated cells was significantly different from IL-1β plus IL-1Ra-treated cells (p < 0.01). B, rat smooth muscle cells were treated with (SAA) or without (Control) SAA (2 μm) or IL-1β (100 ng/ml) for 24 h in the presence (+) or absence (−) of IL-1Ra (1 μg/ml)) for 24 h, at which time media were harvested and assayed for enzyme activity. The data are expressed as nmol of product/min/cm² ± S.D. (n = 3). Enzyme activity in the media of control-treated cells was significantly different from that in SAA-, IL-1β-, and SAA plus IL-1Ra-treated cells (p < 0.001). Enzyme activity in the IL-1β-treated cells was significantly different from that in IL-1β plus IL-1Ra-treated cells (p < 0.001). Enzyme activity in IL-1Ra-treated cells was significantly different from that in SAA plus IL-1Ra-treated cells (p < 0.001).