Fig. 6

Expression of COX-1 and COX-2 transcripts of cultured pulpal fibroblasts after incubation with E. coli LPS (20 μ g/mL) and/or various concentrations of exogenous melatonin. After 3 h of incubation with E. coli LPS, while COX-1 mRNA expression was remained unaffected, COX-2 was increased when incubated with LPS alone (6A). Relative densities of the bands from one of 3 independent experiments yielding similar results were shown (6A, 6C). Addition of exogenous melatonin suppressed basal COX-2 expression (6A, 6B). Loss of LPS antagonism by melatonin after 24 h of incubation was observed (6C, 6D). Asterisk (*) indicates statistical difference at P-value < 0.05 as determined by One-way ANOVA with Bonferroni’s multiple comparisons