Fig. 4. Effect of bacterial PAMPs and allergic mediators on expression of RANKL and OPG mRNA in human PDL fibroblasts. (A) The human PDL fibroblasts were stimulated with either 20 µg/ml LPS, 50 µg/ml PGN, 1 µM trypsin, 1 Unit thrombin, 50 µg/ml GCE, or 50 µg/ml HDM for 24 h. The total mRNA of the stimulated human PDL fibroblasts was extracted and amplified with RANKL, OPG, and GAPDH specific primers. (B, C) The expression levels of RANKL and OPG were quantified after the value was normalized to the expression level of GAPDH. Data are a mean±SE of values from three independent experiments. ^*p<0.05 versus control.