Immunohistochemical and mRNA expression of RANK, RANKL, OPG, TLR2 and MyD88 during apical periodontitis progression in mice

Abstract

Objective To evaluate and correlate, in the same research, the mRNA expression and the staining of RANK, RANKL, OPG, TLR2 and MyD88 by immunohistochemistry in the apical periodontitis (AP) progression in mice.Material and Methods AP was induced in the lower first molars of thirty-five C57BL/6 mice. They were assigned to four groups according to their euthanasia periods (G0, G7, G21 and G42). The jaws were removed and subjected to histotechnical processing, immunohistochemistry and real-time reverse transcription-PCR (qRT-PCR). Data were analyzed with parametric and nonparametric tests (α=0.05).Results An increase of positive immunoreactivity for RANK, RANKL, OPG, TLR2 and MyD88 was observed over time (p<0.05). The RANKL expression was different between the groups G0 and G42, G21 and G42 (p=0.006), with G42 presenting the higher expression in both comparations. The OPG expression was statistically different between the groups G0 and G7, G7 and G21 and G7 and G42 (p<0.001), with G7 presenting higher expression in all the time points. The TLR2 expression was different between the groups G0 and G42 (p=0.03), with G42 showing the higher expression. The MyD88 expression presented a statistical significant difference between groups G7, G21 and G42 compared with G0 (p=0.01), with G0 presenting the smallest expression in all the comparisons. The Tnfrsf11/Tnfrsf11b (RANKL/OPG) ratio increased with the AP progression (p=0.002). A moderate positive correlation between MyD88 and RANKL (r=0.42; p=0.03) and between MyD88 and TLR2 (r=0.48; p<0.0001) was observed.Conclusion The expression of the RANK, RANKL, OPG, MyD88 and TLR2 proteins as well as the ratio Tnfrsf11/Tnfrsf11b (RANKL/OPG) increased with AP progression. There was also a moderate positive correlation between the expression Myd88-Tnfrsf11 and Tlr2-Myd88, suggesting the relevance of Tlr2-Myd88 in bone loss due to bacterial infection.

Butyrate Stimulates Histone H3 Acetylation, 8-Isoprostane Production, RANKL Expression, and Regulated Osteoprotegerin Expression/Secretion in MG-63 Osteoblastic Cells

“…Osteoblasts may affect osteoclast activity through the osteoprotegerin (OPG)/receptor activator of nuclear factor kappa-B (RANK)/RANK ligand (RANKL) system [15]. An increase in RANK, RANKL and OPG expression in the progression of periodontitis and apical periodontitis has been reported [16,17,18]. An increased ratio of RANKL/OPG can be a marker showing the presence of periodontitis and bone resorption [18].…”

Association between Estrogen, Vitamin D and Microrna17 Gene Polymorphisms and Periapical Lesions

“…In addition, RANKL is the mediator responsible for binding to RANK, a surfaceexpressed receptor of osteoclasts and their progenitors, macrophages present in the bone marrow that after this binding receive the stimulation of maturation and conversion into active osteoclasts. The OPG is a soluble receptor secreted by osteoblast anabolic stimuli through which competes with RANK for binding to RANKL agent, thereby preventing this link, so as to inhibit osteoclast genesis (13,(34)(35)(36)(37)(38)(39). Therefore, we hypothesize that genetic polymorphisms in genes that encode molecules involved in this triad are candidates to PAP in humans.…”

Butyrate Stimulates Histone H3 Acetylation, RANKL Expression, But Inhibited Osteoprotegerin Expression/Secretion in MG-63 Osteoblastic Cells

“…Osteoblasts may affect osteoclast activity through OPG/RANK/RANKL system [15]. An increase in RANK, RANKL and OPG expression in the progression of periodontitis and apical periodontitis has been reported [16][17][18].…”