Can apical periodontitis affect serum levels of CRP, IL-2, and IL-6 as well as induce pathological changes in remote organs?

The aim of this study was to investigate whether apical periodontitis (AP) could cause systemic cytokine elevation and pathological changes in remote organs in an experimental animal model. AP was induced in 36 Sprague Dawley (SD) rats. Serum levels of C-reactive protein (CRP), interleukin 2 (IL-2), and interleukin 6 (IL-6) were measured by enzyme-linked immunosorbent assays at different time intervals (0, 6, 12, 24, 48, and 96 h and 1, 2, 3, 4, 5, and 6 weeks) after pulp exposure. Multiple organs (the aortic arch, myocardium, liver, and spleen) were collected for histological observation. The results were analyzed by one-way analysis of variance (ANOVA). Serum levels of CRP, IL-2, and IL-6 were significantly elevated at all time points assessed after 6, 24, and 96 h, respectively. The peak values of serum cytokines (CRP 6.363 +/- 0.05 ng/ml, IL-2 21.997 +/- 0.15 ng/L, and IL-6 2.406 +/- 0.02 ng/L) were reached at 1, 4, and 2 weeks, respectively, followed by a decline. Time-dependent reversible histopathological changes were detected in the aortic arch, myocardium, and spleen, whereas irreversible changes were found in the liver. AP elevated the levels of CRP, IL-2, and IL-6 in rat blood serum, causing reversible changes in the aortic arch, myocardium, and spleen as well as irreversible changes in the liver. AP may trigger a systemic immune response, impair remote organs, and affect the general health of patients.