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Figure 3. Cytokine and COX2 mRNA expression in inflamed pulp and the effects of L-NAME on their expression. (A) Cytokine and COX2 mRNA expression was evaluated with RT-PCR, and the density of each band was measured with Scion Image software. The peak expression of the pro-inflammatory cytokines (IL1{alpha}, IL1ß, and TNF{alpha}) and COX2 occurred at 6 hrs after the application of LPS (n = 3). The expression of IL10, which is one of the anti-inflammatory cytokines, was first observed at 6 hrs. The relative intensities of chemical mediators in each period were: (IL1a) 0.2 ± 0.11, 0 hr; 0.41 ± 0.17, 3 hrs; 0.83 ± 0.3, 6 hrs; 0.23 ± 0.15, 9 hrs; 0.17 ± 0.14, 12 hrs; 0.15 ± 0.1, 24 hrs; (IL1b) 0.2 ± 0.02, 0 hr; 0.81 ± 0.03, 3 hrs; 1.84 ± 0.38, 6 hrs; 1.22 ± 0.38, 9 hrs; 0.85 ± 0.13, 12 hrs; 0.88 ± 0.12, 24 hrs; (IL6) 0 ± 0, 0 hr; 1.21 ± 0.29, 3 hrs; 1.37 ± 0.43, 6 hrs; 1.02 ± 0.18, 9 hrs; 0.73 ± 0.17, 12 hrs; 0.27 ± 0.18, 24 hrs; (IL10) 0 ± 0, 0 hr; 0 ± 0, 3 hrs; 0.43 ± 0.11, 6 hrs; 0.27 ± 0.03, 9 hrs; 0.09 ± 0.01, 12 hrs; 0.08 ± 0.01, 24 hrs; (TNF{alpha}) 0 ± 0, 0 hr; 0.2 ± 0.15, 3 hrs; 1.03 ± 0.41, 6 hrs; 0.6 ± 0.24, 9 hrs; 0.04 ± 0.01, 12 hrs; 0 ± 0, 24 hrs; and (COX2) 0.02 ± 0.01, 0 hr; 0.62 ± 0.07, 3 hrs; 0.75 ± 0.1, 6 hrs; 0.66 ± 0.09, 9 hrs; 0.01 ± 0.01, 12 hrs; and 0.01 ± 0.01, 24 hrs (mean ± SD). The relative intensities of each period were statistically compared, by ANOVA and Tukey-Kramer tests (p < 0.05), with those in untreated pulp samples. (B) Cytokine and COX2 mRNA expression in inflamed pulp (6 hrs after LPS application) treated with or without L-NAME (n = 3, respectively) was evaluated by RT-PCR, and the density of each band was measured with Scion Image software. Each pro-inflammatory cytokine/COX2 mRNA expression was inhibited by the application of L-NAME. In contrast, IL6 and IL10 mRNA expression was not influenced by the application of L-NAME. The relative intensities of chemical mediators at 6 hrs after LPS application in the absence and presence of L-NAME were: (IL1{alpha}) 0.85 ± 0.13 and 0.26 ± 0.19; (IL1b) 1.7 ± 0.2 and 0.26 ± 0.17; (IL6) 1.2 ± 0.2 and 1.0 ± 0.29; (IL10) 0.42 ± 0.12 and 0.4 ± 0.14; (IL12) 0.2 ± 0.14 and 0 ± 0; (TNF{alpha}) 0.81 ± 0.23 and 0.26 ± 0.13; and (COX2) 0.9 ± 0.09 and 0.49 ± 0.21 (mean ± SD). The relative intensities of each mediator in the presence of L-NAME were statistically compared, by ANOVA and Tukey-Kramer tests (p < 0.05), with those in the absence of L-NAME.