OBJECTIVETo detect the expression of RANKL and OPG protein in the giant cell lesions of jaw and to study the mechanism of this lesion.

METHODSRANKL and OPG were detected by immunohistochemistry (SP) in 24 paraffin-embedded and 2 frozen specimens of central giant cell lesion of jaw.

RESULTSRANKL signals were strongly positive in the vascular epithelial cells. They also could be found in fibrous stroma, bone matrix, and stromal spindle cells, even in some cytomembrane of multinucleated giant cells. OPG was detected in multinucleated giant cells and a fraction of round mononuclear cells.

CONCLUSIONSActive vascular epithelial cells are contributed to the formation of multinucleated giant cells through regulating RANKL, and RANKL could play its role by paracrine and autocrine, which might be inhibited by OPG.

Giant Cells ; metabolism ; pathology ; Humans ; Jaw Diseases ; metabolism ; pathology ; Osteoclasts ; metabolism ; Osteoprotegerin ; metabolism ; RANK Ligand ; metabolism

OBJECTIVETo investigate the immunolocalization of receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG), and to explore the correlation between their expressions and activity of osteoclast during first mandibular molar eruption.

METHODSMouse mandibles dissected from postnatal day 1.5 to 14.5 were stained respectively for multinucleated osteoclasts using tartrate-resistant acid phosphatase (TRAP) staining, and RANKL and OPG protein expression was examined by immunohistochemical staining.

RESULTSThe two peak values of osteoclast/acreage in the occlusal and basal region were both observed on the P1.5 and P9.5; while the two peak values in the lateral region were on P3.5 and P9.5. During the mouse molar eruption, burst of osteoclastogenesis was associated with high expression of RANKL and low expression of OPG.

CONCLUSIONSRANKL and OPG could have a close relationship with the osteoclast activity and two developmental apexes were observed during the molar eruption. The occlusal movement was relatively stable, meanwhile the temporarily accelerative movement to the basal and lateral regions could occur.

Animals ; Mice ; Mice, Inbred BALB C ; Osteoprotegerin ; immunology ; metabolism ; RANK Ligand ; immunology ; metabolism ; Tooth Eruption ; immunology

The physiological reconstruction of bone is strictly dependent on bone resorption. Bone resorption is believed to be a complicated molecular reaction process that occurs in the microcircumstance of bone tissue. A lot of enzymes and factors take part in this process, yet there are not enough data with reference to the activation of osteoclast, resorption of bone matrix, regulation of bone resorption. In this paper we review the importance of matrix metalloproteinases (MMPs) in transfer of osteoclast and degradation of bone matrix, and the function of receptor activator of NF-kappaB-ligand (RANKL) and osteoprotegerin (OPG) in regulation of bone resorption.
Bone Resorption ; Humans ; Matrix Metalloproteinases ; metabolism ; Osteoclasts ; physiology ; Osteoprotegerin ; physiology ; RANK Ligand ; physiology

OBJECTIVES: The expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) in human periodontal ligament cells (HPDLCs) was investigated by cell culture under continuous static pressure. METHODS: HPDLCs were primarily cultured by tissue explant method and divided into three groups: group A (13-18 years old), group B (19-29 years old), and group C (30-44 years old). CCK-8 was used to detect the proliferation of HPDLCs. The senescence of HPDLCs was detected by senescence-associated β-galactosidase staining. Cells in the three groups were respectively given 0, 1.5, 3, 6, 12, 24, 48, and 72 h of continuous static pressure in vitro. The expression of OPG and RANKL in the supernatant was detected by enzyme-linked immunosorbent assay. RESULTS: After continuous static pressure in vitro for stimulation, the expression of OPG and RANKL changed. The expression of OPG increased with time and age (P<0.01). The expression of RANKL increased with time and decreased with age (P<0.01). The ratio of OPG/RANKL initially decreased, increased with time, and then continued to rise with age (P<0.01). CONCLUSIONS Aging could increase the expression of OPG and the ratio of OPG/RANKL and decrease the expression of RANKL in HPDLCs under continuous static pressure in vitro.
Humans ; Adolescent ; Young Adult ; Adult ; Osteoprotegerin ; RANK Ligand/pharmacology* ; Periodontal Ligament/metabolism* ; Cells, Cultured ; Aging

OBJECTIVETo investigate the influence of high mobility group box 1 (HMGB1) on the expression of interleukin 6 (IL-6), receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG) on periodontal ligament fibroblasts.

METHODSHuman periodontal ligament fibroblasts were stimulated with HMGB1 at concentrations of 10, 30, and 100 ng x mL(-1) for 24 h. RT-PCR and Western blot analysis were performed to check mRNA and protein expression of IL-6, RANKL and OPG on the cells.

RESULTSThe ratio of RANKL/OPG was increased at both mRNA and protein level after HMGB1 stimulation at 10, 30, 100 ng x mL(-1). Inflammatory cytokine IL-6 was upregulated by HMGB1 at the concentration of 100 ng x mL(-1).

CONCLUSIONIncreased ratio of RANKL/OPG and IL-6 on periodontal ligament fibroblasts suggests that HMGB1 might play a role in the pathogenesis and progression of periodontal disease.

Cells, Cultured ; Fibroblasts ; metabolism ; HMGB1 Protein ; metabolism ; Humans ; Interleukin-6 ; metabolism ; Osteoprotegerin ; metabolism ; Periodontal Ligament ; cytology ; RANK Ligand ; metabolism

OBJECTIVE: To detect receptor activator of nuclear factor kappa B ligand (RANKL) expressed on B10 cells in rheumatoid arthritis (RA) and to evaluate the correlation between RANKL-producing B10 cells in RA and clinical features and laboratory parameters, trying to reveal the possible role of B10 cells in the pathogenesis of RA and the potential mechanism of impaired immunosuppressive capacities. METHODS: 25 RA patients and 20 healthy volunteers were enrolled. These RA patients did not received treatment with glucocorticoids, disease-modifying anti-rheumatic drug and biologics during the recent half of a year. The levels of RANKL-producing B10 cells were measured by flow cytometry (FCM) and polymerase chain reaction (PCR). The correlation between the frequencies of RANKL-producing B10 cells in RA and clinical data, laboratory parameters were analyzed. The role of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) in inducing RANKL expression in B10 cells was evaluated by in vitro stimulation assay. Independent samples t test, Pearson and Spearman correlation were used for statistical analysis. RESULTS: B10 cells were capable of producing RANKL at a low level in health controls. The frequencies of RANKL-producing B10 cells were markedly higher in RA patients than in health controls (3.65%±1.59% vs. 2.25%±0.68%, P<0.01). The frequencies of these cells correlated positively with RA tender joint counts, swollen joint counts and disease activity score in 28 joints (DAS28) (r=0.479, P=0.035; r=0.519, P=0.008; r=0.526, P=0.019). However, no correlation was found between these cells and RA patient age, disease duration, or the levels of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF) and anti-citrullinated peptide antibody (ACPA). After in vitro stimulation by TNF-α, but not IL-1β, B10 cells isolated from healthy donors demonstrated fundamentally upregulated expression of RANKL. CONCLUSION Our studies showed the frequencies of RANKL-producing B10 cells were markedly higher in RA patients, and their frequencies were positively correlated with RA tender joint counts, swollen joint counts and DAS28. These findings suggested that B10 cells might be involved in RA bone destruction.
Antirheumatic Agents ; Arthritis, Rheumatoid/metabolism* ; Autoantibodies/metabolism* ; B-Lymphocytes, Regulatory/metabolism* ; Humans ; RANK Ligand/metabolism* ; Rheumatoid Factor

OBJECTIVETo observe the expression of receptor activator of NF-κB ligand (RANKL) and its decoy receptor osteoprotegerin (OPG) during unloading period of dental implants.

METHODSAn animal model of dental implants was established in Beagle dogs. Bone remodeling was tested at 3, 7, 15, 30, 60 and 90 days after the placement of implants. RANKL and OPG mRNA expression were quantified by real-time PCR. Then mandibular bones were resected and some sections were observed.

RESULTSThe most prominent period of bone remodeling occurred at 7 day after the placement of implants (OPG/RANKL mRNA, 2.15 ± 0.1). The expression of RANKL and OPG increased in a time-dependent manner in both soft and hard tissue. After 7 days they gradually decreased.

CONCLUSIONSBoth OPG and RANKL were expressed in peri-implant tissues, and the changing tendency of RANKL and OPGmRNA was consistent with the change of bone remodeling. The active stage for bone remodelling in peri-implant tissues during unloading period is about 7 days after implantation.

Animals ; Bone Remodeling ; genetics ; Dental Implantation ; Dogs ; Male ; Osteoprotegerin ; genetics ; metabolism ; RANK Ligand ; genetics ; metabolism ; RNA, Messenger ; metabolism

OBJECTIVEThis study aimed to detect the immunoexpression of interleukin-21 (IL-21) and receptor activator. of nuclear factor KB ligand (RANKL) in periapical granulomas (PGs) and radicular cysts (RCs). The interaction of IL-21 with RANKL and its role in periapical pathogenesis were also speculated.

METHODSA total of 32 PGs and 23 RCs were selected as experimental samples. Lesion size and occurrence of tenderness were recorded. Up to 10 healthy gingival tissues were collected as normal control samples. All tissues were subjected to immunohistocheincal analysis with anti-human IL-21 and RANKL polyclonal antibodies. The correlations of IL-21 with RANKL, lesion size, and the occurrence of tenderness of the PGs and RCs were evaluated.

RESULTSIL-21-positive cells were detected in all periapical lesion tissues but not in normal tissues. In the cyst group and granuloma group, the corresponding expression levels of IL-21 were 59.92±6.57 and 36.80± 6.81, whereas those of RANKL were 68.81±18.59 and 36.12±14.87, respectively. Moreover, t-test revealed a significantly higher expression of IL-21 and RANKL in RCs than in PGs (P<0.05). IL-21 and RANKL were positively correlated in both PGs and RCs (P<0.05). Furthermore, IL-21 was correlated with lesion size (P<0.05).

CONCLUSIONThis study demonstrated that IL-21 is potentially involved in the pathogenesis of apical periodontitis lesions. A role in the exacerbation of chronic inflammation, as well as in bone resorption, is suspected. Further studies are required to elucidate the specific functions of IL-21 in periradicular inflammatory processes.

Humans ; Inflammation ; Interleukins ; physiology ; NF-kappa B ; metabolism ; Periapical Granuloma ; metabolism ; Periapical Periodontitis ; RANK Ligand ; Radicular Cyst ; metabolism

OBJECTIVETo evaluate the effect of pulsed ultrasound on the expressions of osteoprotegerin (OPG) and receptor activator nuclear factor kappaB ligand (RANKL) during root resorption in a mouse model of orthodontic tooth movement.

METHODSThirty-two male Wistar rats (6-8 weeks old) were randomly assigned into 4 equal groups, including the blank control group, two ultrasound exposure groups with daily local LIPUS stimulation (100 and 150 MW/cm(2)) for 10 days during mechanical loading, and the control group with mechanical loading but not LIPUS exposure. Nickel-titanium closed-coil springs were used to generate 100 g mesial force for 10 days to move the maxillary right first molars. The expression of OPG and RANKL proteins at the compression sites was detected by immunohistochemistry.

RESULTSUltrasound stimulation significantly up-regulated the expression of OPG and down-regulated RANKL expression (P<0.05). The expressions of OPG and RANKL showed significant differences between the two ultrasound exposure groups (P<0.05).

CONCLUSIONUltrasound stimulation might be useful to protect against root resorption and accelerate its repair by regulating the expressions of OPG and RANKL.

Animals ; Male ; Osteoprotegerin ; metabolism ; RANK Ligand ; metabolism ; Rats ; Rats, Wistar ; Root Resorption ; diagnostic imaging ; metabolism ; Ultrasonography, Doppler, Pulsed

OBJECTIVETo investigate the effect of alendronate on the expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) in mouse osteoblasts.

METHODSMouse calvarial osteoblasts cultured in vitro were identified by alkaline phosphatase (ALP) staining and immunofluorescence assay of OPG and RANKL expressions. The second passage of the osteoblasts were treated with different concentrations of alendronate (10(-4) to 10(-7) mol/L) for 48 h, and the changes in OPG and RANKL mRNA and protein expressions were examined using real-time PCR and Western blotting, respectively.

RESULTSThe isolated osteoblasts were positive for ALP and expressed OPG and RANKL. Real-time PCR and Western blotting showed that at the concentration of 1×10(-4) mol/L, alendronate caused an obvious down-regulation of OPG and RANKL expressions in the cells, whereas at lower concentrations, alendronate increased the expressions of both genes with the highest expressions occurring after treatment with 1×10(-5) mol/L.

CONCLUSIONHigh concentrations of alendronate (>1×10(-4) mol/L) decrease the expressions of OPG and RANKL, whereas low concentrations (1×10(-5) to 1×10(-7) mol/L) increase their expressions in mouse osteoblasts cultured in vitro.

Alendronate ; pharmacology ; Animals ; Cells, Cultured ; Mice ; Mice, Inbred BALB C ; Osteoblasts ; drug effects ; metabolism ; Osteoprotegerin ; metabolism ; RANK Ligand ; metabolism