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. Author manuscript; available in PMC: 2011 May 3.
Published in final edited form as: J Periodontal Res. 2008 Apr;43(2):201–211. doi: 10.1111/j.1600-0765.2007.01013.x

Figure 1. Time course of RANKL mRNA expression induced by E.coli and A. actinomycetemcomitans LPS in PDL cells.

Figure 1

RT-PCR shows that RANKL mRNA expression induced by LPS is biphasic, reaching an early peak after 4 h of stimulation and reached the maximum after 18 to 24 hours (A and B). E. coli LPS was a more potent inducer of OPG expression (A), which was already noticeable after 2 h of stimulation and remained essentially constant throughout the 24 h period. A. actinomycetemcomitans Y4 LPS increased OPG mRNA modestly, and this effect was delayed, since it took 18 hours of stimulation to be more evident. Stimulation for periods longer than 24 h did not induce further increases on either RANKL or OPG mRNA expression (data not shown). Also, we did not observe noticeable levels of RANKL mRNA expression by PDL cells in the absence of any stimulation (data not shown). Representative images of three independent experiments.