Clinically, there has been so far no effective way to repair the bone-missing of large extent due to gash, infection and removal of tumor. The solution of this problem can be assisted by the addition of bioactive substances to substrate materials, because the growth of peripheral tissue and the fiber tissue growing the materials can be induced to the direction of bone-tissue by these biomaterials with bioactive peptides. The peptide Arg-Gly-Asp is the point between the integrin which comes from membrane and the ligand. In certain cases, the artificially synthesized RGD can be competitively combined with the integrin on cell surface, and outer-cell information is transmitted into cells, which will cause a series of physiological changes in cells. Presently, it is reported that the RGD has the ability to induce the growth of osteoblasts, restrain the adhesion between osteoclasts and substrates. This paper reviews and introduces the progress made with the work of RGD-inducing bone regeneration.
Biocompatible Materials ; Bone Regeneration ; drug effects ; physiology ; Cell Adhesion ; drug effects ; Oligopeptides ; administration & dosage ; chemistry ; pharmacology ; Osteoblasts ; drug effects ; physiology ; Osteoclasts ; drug effects ; physiology ; Tissue Engineering ; methods

Melanocortin is the downstream mediator of leptin signaling and absence of leptin signaling in ob/ob and db/db mice revealed the enhancement of bone formation through the central regulation. While alpha-melanocyte-stimulating hormone (alpha MSH) inhibits the secretion of interleukin-1 alpha and tumor necrosis factor-alpha from the inflammatory cells, alpha MSH can also enhance clonal expansion of pro B cells linked to stimulation of osteoclastogenesis. Therefore, we tested the effect of melanocortin on bones. alpha MSH analogues [6His] alpha MSH-ND and [6Asn] alpha MSH-ND were synthesized and the radio-ligand receptor binding- and cyclic AMP generating activity were analyzed in China Hamster Ovary cell line over- expressing melanocortin receptors. The EC50 of [6His] alpha MSH-ND measured from melanocortin-1, 3, 4 and 5 receptors were 0.008 0.0045, 1.523 0.707, 0.780 0.405, and 250.320 42.234 nM, respectively, and the EC50 of [6Asn] alpha MSH-ND were 16.8 6.94, 271.8 21.95, 8.0 1.21, and 1132.5 635.46 nM, respectively. Four weeks after the subcutaneous injection of the analogues, the body weights in the [6His] alpha MSH-ND and the [6Asn] alpha MSH-ND treated groups (346.0 20.63 g vs. 350.0 13.57 g) were lower than that of the vehicle treated group (375.8 17.31 g, p 0.05). There was no difference in the total femoral BMD measured by dual x-ray absorptiometry among the three groups. Among the three groups, there were no differences in the total numbers of crystal violet positive- or alkaline phosphatase positive colonies, in the expression of Receptor Activator of Nuclear Factor Kappa-B ligand on the tibia and the total number of multinucleated osteoclast-like cells differentiated from primary cultured bone marrow cells. From the above results, no evidence of bone gain or loss was found after treatment of the alpha MSH analogues peripherally.
Animal ; Body Weight/drug effects ; Bone and Bones/*drug effects ; CHO Cells ; Cyclic AMP/biosynthesis ; Eating/drug effects ; Hamsters ; Male ; Osteoblasts/drug effects/physiology ; Osteoclasts/drug effects/physiology ; Rats ; Rats, Sprague-Dawley ; Receptors, Corticotropin/physiology ; alpha-MSH/analogs & derivatives/*pharmacology

AIMTo study the effects of fluoride (F-) on ionized calcium ([Ca2+]i) and calcium channel in osteoblast-like cell (OBLs).

METHODSInvestigating [Ca2+]i was by fluorospectrophotometry and recording the calcium currents of OBLs was using whole patch-clamp technique.

RESULTSThe addition of fluoride to the medium made a rapid and significant increase in free [Ca2+]i, especially in 100 ng F- /ml group. There were significances between control group and 50, 100 ng F- /ml groups. And 25 ng/ml F- could stimulate OBLs calcium channel open. Compared with control group, fluoride could significantly increase the amplitudes of calcium currents (P < 0.01), furthermore the activation was in dose-dependent manner.

CONCLUSIONFluoride can make calcium channel open and then increase the concentrations of [Ca2+]i.

Calcium ; physiology ; Calcium Channels ; physiology ; Cell Line ; Fluorides ; toxicity ; Humans ; Osteoblasts ; cytology ; drug effects ; metabolism ; Patch-Clamp Techniques

OBJECTIVETo study influence of serum containing Liuwei Dihuang decoction (see text) on proliferation and differentiation of osteoblast form neonatal SD rats cultured in vitro at different times and different stretch stress.

METHODSAfter osteoblast cultured for 24 hours in the serum containing Liuwei Dihuang decoction (see text) and serum in control group, the 0.5 Hz frequency, 6% and 12% stretch-stress were added. The MTT1 and the activity of ALP were measured at the 12th and 24th hours, and the data were analyzed.

RESULTS1. In the environment of stretch stress to the frequency of 0.5 Hz, and stretched for 24 hours, the osteoblast was stimulated under elongation rate of 6% and 12%; the proliferation and differentiation of osteoblast was more active under elongation rate of 12% than that of 6%. 2. There were no stimulating effects on osteoblast proliferation and differentiation of serum containing Liuwei Dihuiang decoction (see text) acted on osteoblast cells of SD rats cultured in vitro for a shot time.

CONCLUSIONStretch stress environment can enhance osteoblast proliferation and differentiation cultured in vitro.

Alkaline Phosphatase ; metabolism ; Animals ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Male ; Osteoblasts ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley ; Serum ; Stress, Mechanical

OBJECTIVETo investigate the effects of insulin-like growth factor II (IGF-II) on promoting cell proliferation, regulating levels of cellular nitric oxide (NO) and mRNA transcriptions of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) in mouse osteoblast-like cells.

METHODSMouse osteoblastic cell line MC3T3-E1 was selected as the effective cell of IGF-II. After the cells were treated with IGF-II at different concentrations for different time duration, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay was used to examine cell proliferation, and nitrate reductase method was applied to detect NO concentrations in cell culture supernatants and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to determine transcription levels of cellular iNOS and eNOS mRNAs.

RESULTSAfter the MC3T3-E1 cells were treated with IGF-II at concentration of 1 ng/ml for 72 h, 10 and 100 ng/ml for 24, 48 and 72 h respectively, all the MTT values increased (P<0.05 or P<0.01) with obvious dosage-time dependent pattern. NO levels of the MC3T3-E1 cells treated with 100 ng/ml IGF-II for 48 h, and with 1, 10 and 100 ng/ml IGF-II for 72 h were remarkably lower than that of the normal control, respectively (P<0.05 or P<0.01). After the cells were treated with 100 ng/ml IGF-II for 48 h cellular iNOS mRNA levels were significantly decreased (P<0.01). But the levels of eNOS mRNA in the cells treated with each of the used IGF-II dosages for different time duration did not show any differences compared with the normal control (P>0.05).

CONCLUSIONIGF-II at different concentrations could promote proliferation of mouse MC3T3-E1 cell. This cell proliferation promotion was associated with the low NO levels maintained by IGF-II. Higher concentration of IGF-II could down-regulate iNOS gene expression at the level of transcription but not affect transcription of eNOS mRNA, which might be one of the mechanisms for IGF-II maintenance of the low NO levels in MC3T3-E1 cells.

3T3 Cells ; Animals ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Gene Expression Regulation, Enzymologic ; drug effects ; physiology ; Insulin-Like Growth Factor II ; administration & dosage ; Mice ; Osteoblasts ; cytology ; drug effects ; physiology

OBJECTIVETo study the effect of inactivated and un-inactivated pharmaco-serum of diabetic rats fed with Chinese herbs Qianggubao decoction on the proliferation of osteoblast cells (OB)cultured in vitro.

METHODSOB was isolated from the skull of newly born SD rats aged 1 to 2 days by means of Trypsin-collagenase digestion and identified by image analysis under inverted microscope, V-G collagen staining, ALP staining, calcification nod staining etc. After the OB was identified, in activated and un-inactivated pharmaco-serum of diabetic rats fed with Qianggubao decoction of ferent phase (rats were fed with medicine 3 days or 5 days after last fed with medicine 1 hour or 3 hours) and concentration (5%, 10%, 20%) were added to the OB and incubated. After determined times, the effects of the proliferation of osteoblasts were detected by MTT analysis.

RESULTSThere was significant difference between un-inactivated pharmaco-serum and inactivated pharmaco-serum on the proliferation of osteoblasts, and un-inactivated serum had stronger effects to improve the proliferation of osteoblasts (P < 0.01 or P < 0.05).

CONCLUSIONUn-inactivated and inactivation pharmaco-serum of diabetic rats fed with Chinese herbs Qianggubao decoction can influence the proliferation of, and the un-inactivated pharmaco-serum has stronger effects.

Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Diabetes Mellitus, Experimental ; blood ; Drugs, Chinese Herbal ; pharmacology ; Female ; Male ; Osteoblasts ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effects of lipopolysaccharides (LPS) extracted from Porphyromonas endodontalis (Pe) on the expression of macrophage colony stimulating factor (M-CSF) mRNA and protein in MC3T3-E1 cells and the role of nucler factor-κB (NF-κB) in the process.

METHODSMC3T3-E1 cells were treated with different concentrations of Pe-LPS (0-50 mg/L) and 10 mg/L Pe-LPS for different hours (0-24 h). The expression of M-CSF mRNA and protein was detected by reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunoadsordent assay (ELISA). The cells untreated by Pe-LPS served as control. The expression of M- CSF mRNA and protein was also detected in 10 mg/L Pe- LPS treated MC3T3-E1 cells after pretreated with BAY 11-7082 for 1 h, a special NF-κB inhibitor. The groups were divided as follows, control group, BAY group (10 µmol/L BAY 11-7082 treated alone MC3T3-E1 cells), Pe-LPS group (10 mg/L Pe-LPS stimulated MC3T3-E1 cells for 6 h), BAY combine with Pe-LPS group (10 µmol/L BAY 11-7082 pretreated cells for 1 h and 10 mg/L of Pe-LPS stimulated MC3T3-E1 cells for 6 h).

RESULTSThe level of M- CSF mRNA and protein increased significantly after treatment with different concentrations of Pe-LPS (0-50 mg/L), which indicated that Pe-LPS induced osteoblasts to express M-CSF mRNA and protein in dose dependent manners. The expression of M-CSF protein increased from (35 ± 2) ng/L (control group) to (170 ± 8) ng/L (50 mg/L group). Maximal induction of M-CSF mRNA expression was found in the MC3T3- E1 cells treated with 10 mg/L Pe-LPS for 6 h. After 6 h, the expression of M-CSF mRNA decreased gradually. The expression of M-CSF protein also increased with the treatment of 10 mg/L Pe-LPS for 10 h [(122 ± 4) ng/L]. After 10 h, the expression of M-CSF protein decreased gradually. The mRNA and proteins of M-CSF decreased significantly after pretreatment with 10 µmol/L BAY 11-7082 for 1 h. There was no significant difference between BAY group and the control.

CONCLUSIONSPe-LPS may induce the expression of M-CSF mRNA and protein in MC3T3-E1 cells through the signaling of NF-κB.

Animals ; Lipopolysaccharides ; pharmacology ; Macrophage Colony-Stimulating Factor ; drug effects ; physiology ; Mice ; NF-kappa B ; metabolism ; Nitriles ; Osteoblasts ; drug effects ; metabolism ; Porphyromonas endodontalis ; RNA, Messenger ; Signal Transduction ; Sulfones

OBJECTIVETo seek for the appropriate concentration, at which IGF-II can exerts its strong effects on postirradiation proliferation, physiological function and differentiation of the rat's osteoblast-like cells (ROB).

METHODSThe osteoblast-like cells used were isolated from the calvariae of neonatal (one-day-old) SD rats by sequential enzymatic digestion. The third passages of the cells were irradiated with gamma-ray from a (60)Co source at the doses of 100, 400, 600, and 900 cGy. The medium was changed immediately after irradiation and 5 concentrations of IGF-II, i.e., 0, 0.1, 1.0, 10.0, and 100.0 microgram/L were added. 6 days after radiation (9 days in culture), the examination, or the measurement of relative cell number, was carried out.

RESULTSRadiation inhibited the ROB, even lethally. IGF-II completely counteracted the inhibitory effects when the cells were exposed to the radiation at lower dose (100 cGy), and partially when at higher dose (400 cGy). But after the radiation at much higher dose as 900 cGy, the damages were irreversible, even with the existence of this growth factor.

CONCLUSIONSAt least a portion of effective recovery of postirradiation damages may be due to IGF-II-induced radioresistance. Incubation with IGF-II can increase radioresistance or repair of radiation-induced cells damages. However, this effect depends on the dose of radiation.

Animals ; Cell Division ; drug effects ; radiation effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Dose-Response Relationship, Radiation ; Insulin-Like Growth Factor II ; pharmacology ; Osteoblasts ; drug effects ; physiology ; radiation effects ; Radiation Tolerance ; drug effects ; Rats ; Rats, Sprague-Dawley

In order to investigate the roles of Wnt signal pathway in transformation of cardiac valvular myofibroblasts to the osteoblast-like phenotype, the primary cultured porcine aortic valve myofibroblasts were incubated with oxidized low density lipoprotein (ox-LDL, 50 mg/L), and divided into four groups according to the ox-LDL treatment time: control group, ox-LDL 24-h group, ox-LDL 48-h group, and ox-LDL 72-h group. Wnt signal pathway blocker Dickkopf-1 (DDK-1, 100 μg/L) was added in ox-LDL 72-h group. The expression of a-smooth muscle actin (α-SMA), bone morphogenetic protein 2 (BMP2), alkaline phosphatase (ALP), and osteogenic transcription factor Cbfa-1 was detected by Western blotting, and that of β-catenin, a key mediator of Wnt signal pathway by immunocytochemical staining method. The Wnt/β-catenin was observed and the transformation of myofibroblasts to the osteoblast-like phenotype was examined. The expression of α-SMA, BMP2, ALP and Cbfa-1 proteins in the control group was weaker than in the ox-LDL-treated groups. In ox-LDL-treated groups, the protein expression of a-SMA, BMP2, ALP, and Cbfa-1 was significantly increased in a time-dependent manner as compared with the control group, and there was significant difference among the three ox-LDL-treated groups (P<0.05 for all); β-catenin protein was also up-regulated in the ox-LDL-treated groups in a time-dependent manner as compared with the control group (P<0.05), and its transfer from cytoplasm to nucleus and accumulation in the nucleus were increased in the same fashion (P<0.05). After addition of DKK-1, the expression of α-SMA, bone-related proteins and β-catenin protein was significantly reduced as compared with ox-LDL 72-h group (P<0.05). The Wnt/ β-catenin signaling pathway may play an important role in transformation of valvular myofibroblasts to the osteoblast-like phenotype.
Actins ; metabolism ; Animals ; Aortic Valve ; cytology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Gene Expression Regulation ; drug effects ; Intercellular Signaling Peptides and Proteins ; pharmacology ; Lipoproteins, LDL ; pharmacology ; Myofibroblasts ; drug effects ; Osteoblasts ; physiology ; Phenotype ; Swine ; Wnt Signaling Pathway ; drug effects ; beta Catenin ; metabolism

OBJECTIVETo investigate the effects of serum containing Gumibao (Chinese character: see text) on the proliferation and differentiation of osteoblast induced by dexamethasone.

METHODSOsteoblasts were extracted from skulls in newly born (within 24 hours) SD rats, and digested with collagenase. The first passage of cells were used for experiments. Cells were cultured in the medium containing different concentrations of dexamethasone (0, 10(-8), 10(-7), 10(-6), 10(-5) ,10(-4) mol/L). Alkaline phosphatase staining were carried out after 1 week and numbers of mineralized nodes with alizarin red staining were observed after 3 weeks. Accordingly, following the treatment of 10(-5) mol/L dexamethasone for 1 week, cells were cultured in the medium with serum containing Gumibao (Chinese character: see text). One week after Cumibao (Chinese character: see text) treatment, cells were stained with Alkaline phosphatase and collagen I and PCNA were examined by Western-blot. However, the observation of numbers of mineralized nodes with alizarin red stain required one more week.

RESULTSHigh concentration of dexamethasone could inhibit the expression of PCNA, collagen I, alkaline phosphatase and reduce the number of mineralized nodes of osteoblast, while serum containing Gumibao (Chinese character: see text) could reverse the inhibition.

CONCLUSIONHigh concentration of dexamethasone could inhibit the proliferation and differentiation of osteoblastic cells, while serum containing Gumibao (Chinese character: see text) could reverse the inhibition.

Animals ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Collagen Type I ; analysis ; Dexamethasone ; pharmacology ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; pharmacology ; Female ; Osteoblasts ; cytology ; drug effects ; physiology ; Proliferating Cell Nuclear Antigen ; analysis ; Rats ; Rats, Sprague-Dawley