Kinetics of RANKL, RANK and OPG expressions in experimentally induced rat periapical lesions.
OBJECTIVE
The object of this study was to elucidate the kinetics of receptor activator of NFkB ligand (RANKL), RANK, osteoprotegerin (OPG), and cytokine expressions in experimentally induced rat periapical lesions.


METHODS
The mRNA expressions of RANKL, RANK, OPG, and cytokines in experimentally induced rat periapical lesions were evaluated by real-time PCR. The lesions were induced in male Wistar rats (n = 48, 5 weeks of age) by unsealed pulp exposure of the lower first molars.


RESULTS
Expression of RANKL was up-regulated at the beginning of lesion expansion, and expression ratio of RANKL against OPG, a competitor of RANKL, peaked at 2 and 3 weeks. Expression of inflammatory cytokines, such as TNF-alpha, IL-1alpha, and IL-1beta also increased at this stage, suggesting contribution of synergic effects of RANKL and proinflammatory cytokine signaling to lesion expansion. Most of RANKL+ cells were fibroblastic, but few of them were T cells.


CONCLUSIONS
Expression of RANKL and proinflammatory cytokines was correlated with periapical lesion expansion.
Kawashima
Nobuyuki
N
Graduate School of Tokyo Medical and Dental University, Tokyo, Japan. kawashima.n.endo@tmd.ac.jp
Suzuki
Noriyuki
N
Yang
Guangyan
G
Ohi
Chie
C
Okuhara
Shigeru
S
Nakano-Kawanishi
Hiromi
H
Suda
Hideaki
H
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D016207:Cytokines / Q000096:biosynthesis*; D007124:Immunoenzyme Techniques; D016753:Interleukin-10 / Q000096:biosynthesis; D053582:Interleukin-1alpha / Q000096:biosynthesis; D053583:Interleukin-1beta / Q000096:biosynthesis; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D008297:Male; D053244:Osteoprotegerin / Q000096:biosynthesis*; D010485:Periapical Periodontitis / Q000378:metabolism* / Q000473:pathology; D053245:RANK Ligand / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000096:biosynthesis*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071681:Tartrate-Resistant Acid Phosphatase; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D016207:Cytokines; D053582:Interleukin-1alpha; D053583:Interleukin-1beta; D007527:Isoenzymes; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D016693:Receptors, Antigen, T-Cell, alpha-beta; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase