IL-1b synthesis induced by FnLPS in the presence or absence of IL-1ra
Stimulation of HDP with increasing concentrations of FnLPS resulted in dose-dependent IL-1b production ranging from 0.01 to 100 ng mL_1.When 1000 ng mL_1 IL-1rawas added to FnLPS-stimulated cells, a significant reduction in IL-1b levels was observed, regardless of the amount of LPS used to stimulate the cells (P < 0.05) (Fig.1).
HDPIL -1b production induced by FnLPS and IL-1ra Stimulation of HDP with 1-10 ng mL_1 IL-1ra in the presence of10 ng mL_FnLPS did not result in a significant reduction in IL-1bsynthesis. However, when 100- 1000 ng mL_1 IL-1ra was added to FnLPS-treated cells, a significant reduction (P < 0.05) in IL-1b levels was observed (Fig. 2). Effects of IL-1ra when added simultaneously with or after FnLPS stimulation
The addition of1000 ng mL_1IL-1ra,30 min before or at the same time as adding10 ngmL_1 FnLPS resulted in a significant reduction (P < 0.05) in IL-1b synthesis. The production of IL-1bwas also reduced when IL-1ra was added 60 min after treatment by FnLPS (Fig. 3).
Immunolocalization of IL-1ra Only a few macrophages and vascular endothelial cells showed weak staining in normal human dental pulpal tissue (Fig. 4), where a strong positive staining of IL-1ra was observed in numerous neutrophils, plasmacytes, lymphocytes and vascular endothelial cells in inflamed pulpal tissues (Fig. 5).

Figure 1. FnLPS with or without 1000 ng mL IL-1ra-induced IL-1bsynthesis (*P < 0.05; **P < 0.01).



Figure 2. HDP IL-1bproduction induced by FnLPS and different concentrations of IL-1ra (*P < 0.05; **P < 0.01).



Figure 3.Effects of IL-1 rawhen added simultaneously or after stimulation of FnLPS (*P < 0.05; **P < 0.01).



Figure 4.Immunohistochemical localization of IL-1ra in the normal pulp (original magnification x20).



Figure 5.Immunohistochemical localization of IL-1ra in the inflamed dental pulp (original magnification x40).