OBJECTIVETo compare the effects of 8-prenylnaringenin (PNG) and naringenin (NG) on the activity and apoptosis of osteoclasts cultured in vitro, in order to study physiological activity of 8-prenyl perssad.

METHODOsteoclasts were separated from long-limb bones of newly born rabbits, cultured in alpha-MEM containing 10% FBS, and then added with PNG and NG with the concentration of 1 x 10(-5) mol x L(-1). They were stained with TRAP and determined for enzymatic activity with TRAP after 4 d, and analyzed by toluidine blue staining after 7 d. The apoptotic osteoclasts were analyzed by Annexin V-FITC staining after 2, 4, 8, 12, 24, 36, and 48 hours, to observe their apoptosis. Their total RNAs were extracted, and analyzed for TRAP and Cathepsin K expressions by Real-time RT-PCR.

RESULTCompared with the control group, both of the PNG group and the NG group showed much less osteoclasts (TRAP positive cells), lower TRAP activity and TRAP and Cathepin K (CTSK) expression, and smaller number of bone resorption pits and areas. The PNG group show lower indexes than the NG group. Additionally, the PNG group reached the apoptotic peak of osteoclasts at 12 h after drug administration, whereas the NG group reached after 24 h. And the former had more apoptotic cells than the latter.

CONCLUSION8-PNG is much more active than NG in inhibiting the resorption of osteoclasts and inducing apoptosis of osteoclasts. Their only difference lies in 8-prenyl perssad, which is proved to be able to enhance the anti-bone resorption activity of 8-prenylnarigenin.

Acid Phosphatase ; metabolism ; Animals ; Bone Resorption ; prevention & control ; Cathepsin K ; metabolism ; Cells, Cultured ; Flavanones ; pharmacology ; Osteoclasts ; drug effects ; Rabbits

This study was aimed to explore the influence of brucine on the early differentiation of osteoblasts and the metabolic pathway of osteoclast in multiple myeloma (MM) and to compare the effects of brucine and bortezomib on MM. The half inhibitory concentration (IC(50)) of brucine and bortezomib on MM cell line U266 was determined by MTT method; the mRNA levels of alkaline phosphatase (ALP), osteocalcin (OC), osteoprotegerin (OPG) and osteoprotegerin ligand (RANKL) were detected by RT-PCR after the supernatant of cultured U266 cells was added into the culture system for inducing the differentiation of osteoblast line MC3T3-E1 and culturing. The results showed that the IC(50)of bortezomib and brucine on U266 cells for 48 hours were 22.4 nmol/L and 0.16 mg/ml respectively. As compared with osteoblasts treated by supernatant of cultured MM cells alone, the mRNA levels of ALP, OC and OPG in osteoblasts treated by brucine combined with supernatant of cultured MM cells were enhanced (p < 0.05), while the RANKL mRNA level was lowered (p < 0.05), moreover the enhanced and lowered degree also was large (p < 0.05). It is concluded that the influence of brucine on metabolism of osteoblasts and osteoclasts in MM may be realized through the regulation of osteoclasts by osteoblasts. The therapeutic efficacy of brucine on MM is superior to bortezomib.
Animals ; Cell Line ; Cell Line, Tumor ; Humans ; Inhibitory Concentration 50 ; Mice ; Multiple Myeloma ; metabolism ; Osteoblasts ; cytology ; drug effects ; metabolism ; Osteoclasts ; cytology ; drug effects ; metabolism ; Strychnine ; analogs & derivatives ; pharmacology

The purpose of this study was to determine whether the Ca2+ signaling pathway is involved in the ability of osteoprotegerin (OPG) to inhibit osteoclast differentiation and maturation. RAW264.7 cells were incubated with macrophage colony-stimulating factor (M-CSF) + receptor activator of nuclear factor-kappaB ligand (RANKL) to stimulate osteoclastogenesis and then treated with different concentrations of OPG, an inhibitor of osteoclast differentiation. The intracellular Ca2+ concentration [Ca2+]i and phosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the different treatment groups were measured by flow cytometry and Western blotting, respectively. The results confirmed that M-CSF + RANKL significantly increased [Ca2+]i and CaMKII phosphorylation in osteoclasts (p < 0.01), and that these effects were subsequently decreased by OPG treatment. Exposure to specific inhibitors of the Ca2+ signaling pathway revealed that these changes varied between the different OPG treatment groups. Findings from the present study indicated that the Ca2+ signaling pathway is involved in both the regulation of osteoclastogenesis as well as inhibition of osteoclast differentiation and activation by OPG.
Animals ; Calcium/*metabolism ; *Calcium Signaling ; *Cell Differentiation/drug effects ; Cell Line ; Cell Survival/drug effects ; Gene Expression Regulation/drug effects ; Macrophage Colony-Stimulating Factor/metabolism ; Mice ; Osteoclasts/*cytology/*drug effects/*metabolism ; Osteoprotegerin/*pharmacology ; RANK Ligand/metabolism

OBJECTIVETo investigate the degradation of electrodeposited calcium phosphate (ECP) coating and calcium phosphate/chitosan (ECPC) coating in vitro.

METHODSOsteoclasts were isolated from neonatal rabbit long bone cavities and incubated with ECP and ECPC coatings. Calcium ion concentrations in the culture medium were analyzed at 3 days and 6 days. The osteoclastic resorption was observed with scanning electron microscope.

RESULTSBoth coatings demonstrated osteoclastic resorption lacunae. The calcium ion concentrations of the culture mediums were decreased when incubated with calcium phosphate coatings (P < 0.05). Compared with coatings cultured with osteoclasts, the calcium ion concentrations of those cultured without osteoclasts were higher on day 3 (P > 0.05) but lower on day 6 (P < 0.05).

CONCLUSIONSBoth ECP and ECPC coatings can be resorbed by osteoclasts in vitro and can dissolve in the culture medium.

Animals ; Calcium ; metabolism ; Calcium Phosphates ; administration & dosage ; metabolism ; Cells, Cultured ; Chitosan ; administration & dosage ; metabolism ; Dental Alloys ; Electrochemistry ; Osteoclasts ; cytology ; drug effects ; metabolism ; Rabbits

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 explore the role of metabolism of fatty substance and osteoclast activity during the process of steroid-induced necrosis of femoral head through mice model inducing and model index measurement.

METHODSForty SD male mice were divided into 2 groups randomly, the control group and the experiment group. After the gluteal injection of colibacillus endotoxin,the experiment group was given gluteal injection of prednisolone acetate 35.5 mg/kg per week, and 2 ml of normal saline to the control group. The mice were killed 12 weeks later and tested the content of Trap-5b, TC and TG of the blood serum. Vitodynamics, bone density were measured and sections of HE staining, Ca2+ and TRACP staining was made then statistic analysis was performanced.

RESULTSThe content of TC, TG and Trap-5b increased apparently (P < 0.01). Large amount of osteoclasts were found in local medullary cavity. There was severe bone loss and decrease of vitodynamics in subchondral bone (P < 0.01) in experiment group.

CONCLUSIONMetabolic disorder of fatty substance is the key pathogenesis of steroid-induced avascular necrosis of femoral head. Decrease of vitodynamics in subchondral bone due to hyperactivity and increase of osteoclast lead to collapse of femoral head directly.

Animals ; Bone Density ; Disease Models, Animal ; Fatty Acids ; metabolism ; Femur Head Necrosis ; metabolism ; physiopathology ; Humans ; Male ; Osteoclasts ; drug effects ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Steroids ; pharmacology

Platinum nanoparticles (PtNP) exhibit remarkable antioxidant activity. There is growing evidence concerning a positive relationship between oxidative stress and bone loss, suggesting that PtNP could protect against bone loss by modulating oxidative stress. Intragastric administration of PtNP reduced ovariectomy (OVX)-induced bone loss with a decreased level of activity and number of osteoclast (OC) in vivo. PtNP inhibited OC formation by impairing the receptor activator of nuclear factor-kappaB ligand (RANKL) signaling. This impairment was due to a decreased activation of nuclear factor-kappaB and a reduced level of nuclear factor in activated T-cells, cytoplasmic 1 (NFAT2). PtNP lowered RANKL-induced long lasting reactive oxygen species as well as intracellular concentrations of Ca2+ oscillation. Our data clearly highlight the potential of PtNP for the amelioration of bone loss after estrogen deficiency by attenuated OC formation.
Animals ; Metal Nanoparticles/*administration & dosage ; Mice ; Mice, Inbred C57BL ; NFATC Transcription Factors/metabolism ; *Osteoclasts/drug effects/physiology ; Osteoporosis/drug therapy ; Ovariectomy/adverse effects ; Oxidative Stress/drug effects ; Platinum/*administration & dosage ; *RANK Ligand/genetics/metabolism ; Reactive Oxygen Species/metabolism ; Signal Transduction

OBJECTIVETo evaluate the roles or effects of oviductus ranae (OR) or oviductus ranae eggs (ORE) in preventing and treating postmenopausal osteoporosis.

METHODSIn vivo experiment: Sixty female adult Wistar rats were randomly divided into 5 groups of 12. To provide an osteoporosis model 4 groups of rats were ovariectomized (OVX), with the 5th being sham operated. Medication commenced 7 days after the operation and lasted continuously for 12 weeks. Sham operated and OVX groups were given equivalent volumes of 5% Tween-80. The other three groups intragastrically received conjugated estrogens (CE), OR or ORE of the corresponding doses. At the 12th week, serum estrogen, bone gla protein (BGP), serum calcium, phosphorus, and alkaline phosphatase (ALP) were assayed; bone mineral densities (BMD) were measured and bone scanning was conducted; uteri were weighed, and weight, volume and length of the femoral bones were determined; and cortical thickness of femoral heads and area of bone trabecula were measured by image analyzer. In vitro experiment: Eighty 10-month old SD rats, with equal numbers of males and females, were randomly divided into 8 groups. Osteoblasts were isolated from neonatal rat calvariae, and the cells were exposed to various concentrations of serum from OR and ORE groups to study the impact of these sera on osteoblastic proliferation, ALP activity and mineralization. Osteoclastic numbers were determined using tartrate resistant acid phosphatase (TRAP).

RESULTSIn vivo experiment: The body weight of the four OVX groups increased significantly (P<0.01). Uterine weight of the CE group was the highest (P<0.01); Compared with the model group, estrogen level, BMD, bone scanning/bone imaging index weight of the femoral bones, cortical thickness of femoral heads in the OR and ORE groups increased significantly (P<0.05, P<0.01); femoral volume in the ORE group increased significantly (P<0.05); and the content of osteocalcin, phosphorus, and ALP in serum decreased significantly (P<0.05, P<0.01). In vitro experiment: Sera from OR and ORE groups had notable effects on the proliferation of osteoblasts (P<0.05 and P<0.01, repsectively) and stimulated the formation of calcium nodes (P<0.05, P<0.01), while the enhancement of ALP activity in osteoblasts was significant (P<0.05, P<0.01). The number of TRAP-positive cells was significantly reduced as well (P<0.01).

CONCLUSIONSOR and its eggs could effectively suppress OVX-induced osteoporosis in rats, and increase bone turnover possibly by both an increase in osteoblastic activity and a decrease in osteoclastic activity. The present study provides evidence that OR and its eggs could be considered a complementary and alternative medicine for the treatment of postmenopausal osteoporosis.

Acid Phosphatase ; metabolism ; Alkaline Phosphatase ; metabolism ; Animals ; Biomarkers ; blood ; Body Weight ; drug effects ; Bone Density ; drug effects ; Bone and Bones ; metabolism ; Calcification, Physiologic ; drug effects ; Cell Count ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Female ; Femur ; drug effects ; metabolism ; pathology ; Isoenzymes ; metabolism ; Male ; Materia Medica ; pharmacology ; therapeutic use ; Organ Size ; drug effects ; Osteoblasts ; drug effects ; enzymology ; pathology ; Osteoclasts ; drug effects ; enzymology ; pathology ; Osteoporosis ; blood ; drug therapy ; metabolism ; physiopathology ; Ovariectomy ; Ovum ; metabolism ; Rats ; Rats, Wistar ; Tartrate-Resistant Acid Phosphatase ; Uterus ; drug effects ; pathology

BACKGROUNDThe cannabinoid receptor-2 (CB2) is important for bone remodeling. In this study, we investigated the effects of CB2 selective antagonist (AM630) on receptor activator of nuclear factor kappa B (RANK) ligand (RANKL) induced osteoclast differentiation and the underlying signaling pathway using a monocyte-macrophage cell line-RAW264.7.

METHODSRAW264.7 was cultured with RANKL for 6 days and then treated with AM630 for 24 hours. Mature osteoclasts were measured by tartrate-resistant acid phosphatase (TRAP) staining using a commercial kit. Total ribonucleic acid (RNA) was isolated and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was done to examine the expression of RANK, cathepsin K (CPK) and nuclear factor kappa B (NF-κB). The extracellular signal-regulated kinase (ERK), phosphorylation of ERK (P-ERK) and NF-κB production were tested by Western blotting. The effect of AM630 on RAW264.7 viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay.

RESULTSAM630 did not affect the viability of RAW264.7. However, this CB2 selective antagonist markedly inhibited osteoclast formation and the inhibition rate was dose-dependent. The dose of ≥ 100 nmol/L could reduce TRAP positive cells to the levels that were significantly lower than the control. AM630 suppressed the expression of genes associated with osteoclast differentiation and activation, such as RANK and CPK. An analysis of a signaling pathway showed that AM630 inhibited the RANKL-induced activation of ERK, but not NF-κB.

CONCLUSIONAM630 could inhibit the osteoclastogenesis from RAW264.7 induced with RANKL.

Animals ; Blotting, Western ; Cell Differentiation ; drug effects ; Cell Line ; Cell Survival ; drug effects ; Indoles ; pharmacology ; Mice ; Osteoclasts ; cytology ; drug effects ; metabolism ; RANK Ligand ; pharmacology ; Receptor, Cannabinoid, CB2 ; antagonists & inhibitors ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects

The OPG/RANKL/RANK system plays an important role in osteoclastogenesis and represents a great progress in bone biology. RANKL, which expresses on the surface of osteoblast/stromal cells and activated T cells, binds to RANK on the osteoclastic precursors or mature osteoclasts, and promotes osteoclastogenesis and bone resorption. While osteoprotegerin (OPG), which is expressed by osteoblasts/stromal cells, strongly inhibits bone resorption by binding to its ligand RANKL and thereby blocks the interaction between BANKL and RANK. A number of cytokines and hormones exert their effects on bone metabolism by regulating the OPG/RANKL ratio in the bone marrow microenvironment. RANK is also expressed on mammary epithelial cells and RANKL expression in these cells is induced by pregnancy hormones, RANKL and RANK are essential for the formation of the lactating mammary gland and the transmission of maternal calcium to neonates in mammalian species. Modulation of these systems provides a unique opportunity to develop novel therapeutics to inhibit bone loss in osteoporosis, rheumatoid arthritis, and bone metastasis of cancer. Further research should be focused on the cooperation of OPG/RANKL/RANK system with other signal pathways and the interactions among bone remodeling, immune system and endocrinology system. Currently, the development of OPG analogues or compounds which may stimulate OPG expression is becoming an attractive industry which may be profitable to both patients and manufacturers.
Animals ; Bone Resorption ; immunology ; metabolism ; Humans ; Osteoclasts ; cytology ; metabolism ; pathology ; Osteogenesis ; drug effects ; genetics ; immunology ; Osteoprotegerin ; metabolism ; physiology ; RANK Ligand ; metabolism ; physiology ; Receptor Activator of Nuclear Factor-kappa B ; metabolism ; pharmacology ; physiology ; T-Lymphocytes ; drug effects ; immunology