Impaired clearance of <i>P. gingivalis</i> by inhibiting iNOS induction in ApoE ^−/− mice.

<p>A and B, in vitro studies: peritoneal macrophages from wild type (WT) and ApoE ^−/− mice were infected with <i>P. gingivalis</i> (MOI = 25∶1) and CFU of internalized bacteria were determined at 1.5 and 15 h after infection. C, in vivo studies: mice were infected i.p. with <i>P. gingivalis</i> (5×10⁷). Serial dilutions of peritoneal fluid were plated for anaerobic growth and enumeration of recovered peritoneal CFU. D, peritoneal macrophages were incubated with FITC-labeled <i>P. gingivalis</i> (MOI = 25∶1) for 30 min. Association (i.e., representing both adherence and phagocytosis) or phagocytic indices were determined by flow cytometry, as described in Materials & Methods, using the following formula: (% positive cells for FITC-P. gingivalis×MFI)/100. E, 24 h after peritoneal infection, the induction of iNOS was determined by Western blot using the cellular components of the peritoneal fluid after centrifugation, data were normalized to GAPDH. F, mouse macrophages were infected with <i>P. gingivalis</i>, and iNOS production was determined by Western blot 24 h post infection (i), and iNOS mRNA was determined by qPCR 2 h post infection (ii). Results were means ±SD (<i>n</i> = 3) and were confirmed in repeated experiments. *, <i>P</i><0.05.