OBJECTIVE: To determine whether resveratrol (Res) can correct osteoporosis induced in a rat model of male hypogonadism. METHODS: Thirty-two rats were randomly divided into 4 groups, 8 in each group; 1) a control sham group: underwent a similar surgical procedure for induction of orchiectomy (ORCD) without ligation of any arteries or veins or removal of the testis and epididymis; 2) a control + Res-treated group (Con+Res): underwent sham surgery similar to the control, but was then treated with Res, as described below; 3) an ORCD-induced group: bilateral ORCD surgery as described above, and 4) a ORCD+Res-treated group: bilateral ORCD surgery followed by Res treatment. Res treatment began 4 weeks after ORCD and continued for 12 weeks. After 12 weeks, bone mineral density (BMD) and bone mineral content (BMC) were measured in the tibia and femur of each rat's right hind leg. Blood levels of bone turnover indicators such as deoxypyridinoline (Dpd), N-telopeptide of type I collagen (NTX I), alkaline phosphatase (ALP), and osteocalcin (OC), as well as receptor activator of nuclear factor kappa B (RANK) and osteoprotegerin (OPG) were assessed. RESULTS: ORCD significantly decreased BMD (P<0.01) and significantly increased bone resorption, manifested by increased RANK. In addition, it inhibited serum levels of OPG and OC. Res treatment after ORCD effectively increased serum levels of bone formation markers such as OPG and OC, compared with testisectomized rats (P<0.05). CONCLUSION Res could ameliorate bone loss induced by male hypogonadism, possible via restoration of the normal balance between RANK and OPG.
Rats ; Male ; Animals ; Bone Density ; Resveratrol/pharmacology* ; Osteoporosis ; Osteoprotegerin/pharmacology* ; Bone Remodeling ; Hypogonadism ; RANK Ligand/pharmacology*

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

OBJECTIVES: This study aims to determine the effects of low-level laser (LLL) on the expression of interleukin-6 (IL-6), tumor necrosis factor (TNF)-α, osteoprotegerin (OPG), and receptor activator of nuclear factor-κB ligand (RANKL) in human periodontal ligament cells (HPDLCs) stimulated by high glucose; and identify the molecular mechanism of LLL therapy in the regulation of periodontal inflammation and bone remodeling during orthodontic treatment in diabetic patients. METHODS: HPDLCs were cultured in vitro to simulate orthodontic after loading and irradiated with LLL therapy. The cultured cells were randomly divided into four groups: low glucose Dulbecco's modification of Eagle's medium (DMEM)+stress stimulation (group A), high glucose DMEM+stress stimulation (group B), hypoglycemic DMEM+LLL therapy+stress stimulation (group C), and hyperglycemic DMEM+LLL therapy+stress stimulation (group D). Groups C and D were further divided into C1 and D1 (energy density: 3.75 J/cm²) and C2 and D2 (energy density: 5.625 J/cm²). Cells in groups A, B, C, and D were irradiated by LLL before irradiation. At 0, 12, 24, 48, and 72 h, the supernatants of the cell cultures were extracted at regular intervals, and the protein expression levels of IL-6, TNF-α, OPG, and RANKL were detected by enzyme-linked immunosorbent assay. RESULTS: 1) The levels of IL-6 and TNF-α secreted by HPDLCs increased gradually with time under static pressure stimulation. After 12 h, the levels of IL-6 and TNF-α secreted by HPDLCs in group A were significantly higher than those in groups B, C1, and C2 (P<0.05), which in group B were significantly higher than those in groups D1, and D2 (P<0.01). 2) The OPG protein concentration showed an upward trend before 24 h and a downward trend thereafter. The RANKL protein concentration increased, whereas the OPG/RANKL ratio decreased with time. Significant differen-ces in OPG, RANKL, and OPG/RANKL ratio were found among group A and groups B, C1, C2 as well as group B and groups D1, D2 (P<0.05). CONCLUSIONS 1) In the high glucose+stress stimulation environment, the concentrations of IL-6 and TNF-α secreted by HPDLCs increased with time, the expression of OPG decreased, the expression of RANKL increased, and the ratio of OPG/RANKL decreased. As such, high glucose environment can promote bone resorption. After LLL therapy, the levels of IL-6 and TNF-α decreased, indicating that LLL therapy could antagonize the increase in the levels of inflammatory factors induced by high glucose environment and upregulate the expression of OPG in human HPDLCs, downregulation of RANKL expression in HPDLCs resulted in the upregulation of the ratio of OPG/RANKL and reversed the imbalance of bone metabolism induced by high glucose levels. 2) The decrease in inflammatory factors and the regulation of bone metabolism in HPDLCs were enhanced with increasing laser energy density within 3.75-5.625 J/cm². Hence, the ability of LLL therapy to modulate bone remodeling increases with increasing dose.
Humans ; Osteoprotegerin ; Tumor Necrosis Factor-alpha/metabolism* ; Interleukin-6/pharmacology* ; RANK Ligand/pharmacology* ; Periodontal Ligament/metabolism* ; Lasers ; Glucose/pharmacology*

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

The bone remodeling process in response to orthodontic forces requires the activity of osteoclasts to allow teeth to move in the direction of the force applied. Receptor activator of nuclear factor-κB ligand (RANKL) is essential for this process although its cellular source in response to orthodontic forces has not been determined. Orthodontic tooth movement is considered to be an aseptic inflammatory process that is stimulated by leukocytes including T and B lymphocytes which are presumed to stimulate bone resorption. We determined whether periodontal ligament and bone lining cells were an essential source of RANKL by tamoxifen induced deletion of RANKL in which Cre recombinase was driven by a 3.2 kb reporter element of the Col1α1 gene in experimental mice (Col1α1.CreER.RANKL) and compared results with littermate controls (Col1α1.CreER.RANKL). By examination of Col1α1.CreER.ROSA26 reporter mice we showed tissue specificity of tamoxifen induced Cre recombinase predominantly in the periodontal ligament and bone lining cells. Surprisingly we found that most of the orthodontic tooth movement and formation of osteoclasts was blocked in the experimental mice, which also had a reduced periodontal ligament space. Thus, we demonstrate for the first time that RANKL produced by periodontal ligament and bone lining cells provide the major driving force for tooth movement and osteoclastogenesis in response to orthodontic forces.
Animals ; Bone Remodeling ; physiology ; Mice ; Mice, Transgenic ; Osteoclasts ; physiology ; Periodontal Ligament ; metabolism ; RANK Ligand ; metabolism ; Tamoxifen ; pharmacology ; Tooth Movement Techniques

Rutin, a glycoside of flavonol, inhibits osteoclast formation induced by receptor activator of NF-kappaB ligand (RANKL) in bone marrow-derived macrophages. It reduces reactive oxygen species produced by RANKL and its inhibitory effect results from reduced levels of TNF-alpha Rutin also lowers NF-kappaB activation in response to RANKL.
Animals ; Mice ; Mice, Inbred C57BL ; NF-kappa B/*metabolism ; Osteoclasts/*cytology/*drug effects ; RANK Ligand/pharmacology ; Reactive Oxygen Species/*metabolism ; Rutin/*pharmacology ; Tumor Necrosis Factor-alpha/*metabolism/pharmacology

OBJECTIVETo study the effects of Zhengqing Fengtongning Tablet (ZFT) and methotrexate (MTX) on the expression of osteoprotegerin (OPG), receptor activator of nuclear factor-kappaB ligand (RANKL), and interleukin 17 (IL-17) in collagen-induced arthritis (CIA) rats, thus addressing their bone protection.

METHODSThe CIA rat model was established by intradermally injecting type II collagen emulsion from the rats' back and tail. Totally 28 successfully modeled rats [with the arthritis index (AI) more than 2] were randomly divided into the model group, the Chinese medicine (CM) treatment group, the MTX group, and the ZFT + MTX treatment group, 7 rats in each group. Another 7 rats were recruited as the normal control group. Rats were administered from the 7th day of modeling. Rats in the MTX group were treated with MTX at 3.8 mg/kg once a week. Those in the CM group were treated with ZFT at the daily dose of 130 mg/kg, once a day. Those in the ZFT + MTX treatment group were treated with both MTX (at 3.8 mg/kg once a week) and ZFT (at the daily dose of 130 mg/kg, once a day). Those in the model group and the normal control group were administered with normal saline of the equal volume by gastrogavage. All the intervention lasted for 26 days. The destruction of joints in the four limbs were observed using X-ray. The AI was recorded. The expression levels of serum OPG, RANKL, and IL-17 were detected at the end of the experiment.

RESULTSDuring the whole process, all rats except those in the model group were in a good condition. On the 21st day of modeling the AI of all rats reached the peak, but it decreased after treatment. Compared with the model group, the AI decreased in the CM treatment group, the MTX group, and the ZFT + MTX treatment group with statistical difference (P < 0.05). Compared with the model group, the OPG increased and RANKL decreased in the MTX group; the OPG and OPG/RANKL increased in the CM treatment group; the OPG, RANKL, and OPG/RANKL increased, and IL-17 decreased in the ZFT + MTX treatment group, all showing statistical difference (P < 0.05). Compared with the MTX and the ZFT + MTX treatment group, OPG/RANKL increased and IL-17 decreased in the ZFT + MTX treatment group (both P < 0.05).

CONCLUSIONZFT + MTX could synergistically elevate peripheral OPG/RANKL and down-regulate IL-17 in CIA model rats.

Animals ; Arthritis, Experimental ; blood ; chemically induced ; drug therapy ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Female ; Interleukin-17 ; blood ; Methotrexate ; pharmacology ; therapeutic use ; Osteoprotegerin ; blood ; RANK Ligand ; blood ; Rats

In dentistry, orthodontic root resorption is a long-lasting issue with no effective treatment strategy, and its mechanisms, especially those related to senescent cells, remain largely unknown. Here, we used an orthodontic intrusion tooth movement model with an L-loop in rats to demonstrate that mechanical stress-induced senescent cells aggravate apical root resorption, which was prevented by administering senolytics (a dasatinib and quercetin cocktail). Our results indicated that cementoblasts and periodontal ligament cells underwent cellular senescence (p21⁺ or p16⁺) and strongly expressed receptor activator of nuclear factor-kappa B (RANKL) from day three, subsequently inducing tartrate-resistant acid phosphatase (TRAP)-positive odontoclasts and provoking apical root resorption. More p21⁺ senescent cells expressed RANKL than p16⁺ senescent cells. We observed only minor changes in the number of RANKL⁺ non-senescent cells, whereas RANKL⁺ senescent cells markedly increased from day seven. Intriguingly, we also found cathepsin K⁺p21⁺p16⁺ cells in the root resorption fossa, suggesting senescent odontoclasts. Oral administration of dasatinib and quercetin markedly reduced these senescent cells and TRAP⁺ cells, eventually alleviating root resorption. Altogether, these results unveil those aberrant stimuli in orthodontic intrusive tooth movement induced RANKL⁺ early senescent cells, which have a pivotal role in odontoclastogenesis and subsequent root resorption. These findings offer a new therapeutic target to prevent root resorption during orthodontic tooth movement.
Rats ; Animals ; Root Resorption/prevention & control* ; Senotherapeutics ; Stress, Mechanical ; Dasatinib/pharmacology* ; Quercetin/pharmacology* ; Osteoclasts ; Tooth Movement Techniques ; Periodontal Ligament ; RANK Ligand

OBJECTIVETo explore the mechanism of Shangke Jiegu Tablet (SJT)in repairing the mandibular defect.

METHODSTotally 72 healthy male New Zealand rabbits were randomly divided into the normal control group (n = 24), the model group (n = 24), and the SJT group (n = 24). Then the mandibular defect model was established. Animals in the normal control group and the model group were fed with normal forage, while those in the SJT group were fed with SJT forage. On the day 7, 14, 28, and 56 after model establishment, 6 rabbits were killed in each group. The bone was collected from the mandibular defect. The gene expressions of osteoprotegerin (OPG) and osteoprotegerin ligand (OPGL) were detected by means of RT-PCR. The positive dyeing strength and area of the bone tissue were detected by means of immunohistochemical technique.

RESULTSCompared with the normal control group, the degree of OPGmRNA expression was remarkably up-regulated on day 7 after model establishment (P < 0.05) and the degree of OPGLmRNA expression was remarkably up-regulated on day 14 after model establishment (P < 0.05) in the model group. Compared with the model group, the degree of OPGmRNA expression was remarkably up-regulated (P < 0.05), and the positive dyeing strength and area of bone tissue were stronger and broader on day 14, 28, and 56 after model establishment in the SJT group. The degree of OPGLmRNA expression was remarkably down-regulated (P < 0.05), and the positive dyeing strength and area of bone tissue were weaker and smaller on day 14 after model establishment in the SJT group. The ratio of OPGmRNA/OPGLmRNA was remarkably up-regulated on day 14, 28, and 56 after model establishment (P < 0.05).

CONCLUSIONThe effect mechanism of promoting mandibular defect repairing by SJT may be correlated to regulating the expressions of OPGmRNA and OPGLmRNA.

Animals ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression ; drug effects ; Ligands ; Male ; Mandibular Injuries ; genetics ; metabolism ; Osteoprotegerin ; metabolism ; RANK Ligand ; metabolism ; Rabbits ; Wound Healing ; drug effects

OBJECTIVETo observe the effect of Icariin (ICA) on serum receptor activator of NFkappaB-ligand (RANKL)/osteoprotegerin (OPG) production and bone destruction in type II collagen-induced arthritis (CIA) rats.

METHODSThe CIA rat model was established in all rats, except those in the normal group (n = 8) using bovine type II collagen and complete Freund's adjuvant. Totally 24 CIA rats with arthritis index (AI) > or = 6 were selected and divided into the model group, the methotrexate (MTX) group, and the ICA group according to the AI score, 8 in each group. Normal saline was given to rats in the normal group and the model group by gastrogavage. MTX at the weekly dose of 5 mg/kg was given to rats in the MTX group. ICA at the daily dose of 20 mg/kg was given to rats in the ICA group. All medication lasted for 4 weeks. The AI scores were recorded once a week. Histomorphologic changes of the ankle joint were observed by HE staining. The bone destruction and the osteoporosis of the foot phalanx were detected by X-ray. Serum levels of RANKL and OPG were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTSAfter 4-week intervention, when compared with the model group, AI score and Larsen score were significantly lower, the serum RANKL concentration and the RANKL/OPG ratio obviously decreased, while the serum OPG concentration obviously increased in the CIA group (P < 0.05, P < 0.01). In the MTX group, the aforesaid indices decreased, but without statistical difference (P > 0.05). Results of HE staining indicated that hyperplasia of joint synovium, infiltration of inflammatory cells, and the degree of articular cartilage destruction were obviously alleviated in the ICA group.

CONCLUSIONICA could alleviate or lessen the degree of articular cartilage destruction in CIA rats, and its mechanism might be associated with reducing serum levels of RANKL and elevating levels of OPG, thus further decreasing the ratio of RANKL/OPG.

Animals ; Arthritis, Experimental ; blood ; pathology ; Collagen Type II ; adverse effects ; Female ; Flavonoids ; pharmacology ; Osteoprotegerin ; blood ; RANK Ligand ; blood ; Rats ; Rats, Wistar