Objective To investigate the influence of different dose levels of hydroxyapatite/tricalcium phosphate (HA/TCP) on the proliferation and alkalinephosphatase (ALP) activity of rabbit osteoblasts. Methods Three different doselevels of HA/TCP (10%, 40%, 70%) were co-cultivated with rabbit osteoblasts respectively. The proliferation and ALP expression capacity of osteoblasts were examined with MTT method and enzyme histochemistry once every 24 hours until 5 days. Three control groups of other materials were treated and examined in the sameway: rabbit osteoblasts as normal control; polyvinylchloride as positive control; titanium alloy as negative control. Results There was remarkable timeeffect relationship in the proliferation of osteoblasts. Ten percent HA/TCP did not affect osteoblasts growth while 40% HA/TCP could slow the cell growth rate down though time-effect relationship still existed. The proliferation of osteoblasts stagnated when co-cultivated with 70% HA/TCP. On the other hand, 10% HA/TCP could cause reversible damage on ALP activity of osteoblasts, whereas when the dose was40%, and the cultivation lasted 6 days the damage was irreversible. Three different dose levels of titanium alloy (10%, 40%, 70%) had no effect on the proliferation or ALP activity of osteoblasts. Conclusion Dosage is an important factor affecting the biocompatibility evaluation of biomaterial. It suggests that dose choosing should be more specified upon each individual biomaterial. It also indicates that ALP may be a good supplementary index of the cell compatibility of material.
OBJECTIVE: To isolate and characterize mesenchymal stem cells (MSCs) derived from bone marrow of Banna minipig inbred line (BMI). METHODS: BMI-MSCs was isolated from bone marrow by density gradient centrifugation and cultured in DMEM (containing 15% bovine serum) at 37 degrees C with humidified 5% CO2. These cultured stem cells were characterized in clonal growth, expression of specific markers and capability of differentiation. RESULTS: Mesenchymal stem cells were proliferative and could be expanded rapidly in vitro. Clonal growth of these cells can be observed when small amount of cells was inoculated. These cells were SH2, SH3, SH4, SB10 and SB21 positive. And it was proved that these cells possess osteo-differentiation ability, up-regulated alkaline phosphatase expression and calcium secretion after osteosupplement was added into the media for several days. CONCLUSION: Mesenchymal stem cells derived from bone marrow of BMI possess the general characters of stem cell.
There is a great hope to treat long bone defects with bioactive artificial bone constructed by osteoblasts and biomaterials, in which the key point is to provide an optimum environment for the normal function of osteoblasts. The cellular sociological characteristics of osteoblasts were summarized and it was suggested that the ideal bioactive artificial bone should be composed of inorganic and organic materials together with cellular components such as osteoblasts and vascular endothelial cells, and combined with control release of growth factors, following its implantation it could be vascularized very soon and merged with the host bone by bony consolidation.
Objective To investigate the effect of WO-1 on the proliferation and differentiation of human embryonic osteoblasts (HEO) and to provide research methods of bone tissue engineering. Methods HEO were isolated from periosteum and calvaria and then cultrued in vitro. The doseeffect relationship between WO-1 concentration and biological effect of HEO was evaluated by growth curve and 3 H-TdR count. The effect of WO-1 on cell activity and proliferation was investigated by cloning efficiency,cell cycle analysis was determined by flow cytometer and morphological was examined through transmission electron microscope. Moreover, the effect of WO-1 on osteoblastic function was evaluated at protein and mRNA levels by ALP activity, 3 H-proline incorporation, osteocalcin secretion (RIA) and mRNA expression of type I collagen and osteocalcin (RT-PCR). Results The proliferation of HEO was inhibited in high concentration of WO-1,while it was promoted in low concentration of WO-1. The optimal dose was 8 μg/ml, and there was dose-effect relationship in the certain range of WO-1 concentration (0.25 μg/ml to 8 μg/ml). In 8 μg/ml of WO-1, the cloning efficiency and cloning volume of HEO were inereased, population doubling time was decreased.All indexes of ostoblastic function including ALP activity, type I collagen synthesis and osteocalcin secertion were inereased, the more sufficed cell organs were observed under transmission electron microscope than control group(P＜0.05). Conclusion WO-1 can promote the cell activity and proliferation of HEO cultured in vitro inlow concentration, enhance the synthesis of extracellular mamix, such as type Icollagen and osteocalcin, and accelerate the mineralization of osteoid. WO-1 can be used as a stimulant of proliferation and differentiation of HEO in the research of bone tissue engineering, which provide the theoretical basis in clinical application.
Objective To analyze MC3T3E1 cell morphology, prol iferation, and osteogenic differentiation in fibrin gel (FG) so as to lay a fundament for use of FG in tissue engneering. Methods MC3T3E1 cells were incubated in three concentrations (20, 10 and 5 mg/mL)of FG as the experimental groups (groups A, B and C) and in the common medium culture as the control group (group D). The cell morphology and distribution in FG were observed by inverted phase contrast microscope and confocal laser scanning microscope at different time. The cell prol iferation was assessed by fluorospectrophotometer. The alkal ine phosphatase (ALP) activity was detected by automatic biochemistry analyses and von Kossa staining was used to analyze calcium salts mineralization. RT-PCR was used to analyze the ALP and bone sialoprotein (BSP)mRNA expression at 14 and 21 days. Results In groups A, B and C, the MC3T3E1 cells had long processes which connected each other and formed network; but fusiform or cube cells were observed in group D at 21 days. The fluorescence intensity was increased gradually with time, was the highest at 14 days and the lowest at 28 days in group D; it was highest in groups A, B and C at 28 days, there were statistically significant differences when compared with group D (P lt; 0.05). The ALP activity was increased gradually with time, and it was the highest at 28 days in group D and at 21 days in groups A and B, there were significant differences (P lt; 0.05), no statistically significant differences compared with group D at other time points (P gt; 0.05). The mineral ization nodus were seen at 21 and 28 days in group A, but no mineral ization nodus was seen in group D at 28 days. The RT-PCR results showed the mRNA expressions of ALP and BSP were enhanced in group A when compared with group D (P lt; 0.05). Conclusion The osteogenic differentiation was most obvious and cell prol iferation was most active after 21 days of incubation in FG.
Objective To summary the functional roles and molecular mechanisms of microRNA (miRNA) in osteoblast differentiation so as to supply information for basic and cl inical researches. Methods Recent l iterature concerning miRNA in osteoblast differentiation was reviewed. The information was classified and summarized. Results miRNAs critically regulate bone morphogenetic protein, transforming growth factor β, and Wnt/β-catenin signal ing pathways during osteoblast differentiation. In pathological conditions, especially in some disorders of abnormal osteoblast differentiation, downregulated miRNA expression has been observed. Conclusion miRNA may represent a novel biomarker for diagnosis, and a candidate target therapies for the disorders with abnormal osteoblast differentiation.
Objective To investigate the effect of transforming growth factor-β1 (TGF-β1) gene transfer on the biological characteristics of osteoblasts. Methods The expression of TGF-β1 in the transfected osteoblasts was detected by in situ hybridization and assay of TGF-β1 activity in the supernatant (minklung epithelium cell growth -inhibition test). The effects of gene transfer andsupernatant of the transfected osteoblasts on the proliferation and alkaline phosphatase(ALP) activity of osteoblasts were detected by 3 H-TdR and MTT. Results The results of in situ hybridization analysis suggested that the osteoblasts transfected by TGF-β1 gene could express TGF-β1 obviously. The complex medium, which was the mixture of serum-free DMEM and the activated supernatant according to 1∶1, 1∶2, 1∶4, could inhibit growth of Mv-1-Lu evidently and the ratios ofinhibition were 16.3%, 22.7%, 28.2% respectively. TGF-β1 gene transfer hadno effect on the biological characteristics of osteoblasts, but the activated supernatant of transfected osteoblasts stimulated proliferation and inhibited ALPactivity of osteoblasts. Conclusion TGF-β1 gene transfer promotes the expression of TGF-β1 and the biological characteristics of trasfected osteoblasts are stable, which is helpful for gene therapy of bone defects in vivo.
Objective To study the biological behavior of osteoblast and vascular endothelial cell culture. Methods The osteoblasts and vascular endothelial cells were obtained from calvarial bone and renal cortox of 2-week rabbits respectively. The experiment were divided into group A (osteoblasts), group B (vascular endothelial cells) and group C(co-cultured osteoblasts and vascular endothelial cells). The cells were identified with cytoimmunochemical staining. The cellular biological behavior and compatibilitywere observed under inverted phase contrast microscope and with histological staining. The cells viability and alkaline phosphatase(ALP) activity were measured. Results The cytoimmunochemical staining showed that the cultured cells were osteoblasts and vascular endothelial cells .The cellular compatibility of osteoblasts and vascular endothelial cells was good. The ALP activity was higher in group C than in group A and group B(P＜0.01), and it was higher in group A than in group B(P＜0.05). In group C, the cellproliferation were increased slowly early, but fast later. Conclusion Thecellular compatibility of osteoblasts and vascular endothelial cells were good. The vascular endothelial cells can significantly increased the osteoblast viability and ALP activity,and the combined cultured cells have greater proliferation ability.
Objective To observe the characteristics and related gene expression of osteoblastic differentiation in porcine bone marrow mesenchymal stem cells (MSCs) during. Methods Bone marrow from 6 landrace pigs, 3-month-old about 50 kg, was aspirated from the medullary cavity of the proximal tibia. The MSCs were isolated, and purified by Ficoll density gradient centrifugation combined with adherent culture method. The MSCs from passage 1 were cultivated in DMEM with 1×10-8mmol/L dexamethasone (Dex), 10 mmol/L β-glycerophosphate (β-GP), 82 μg/ml ascorbic acid (Asc) and 10% inactivated fetal bovine serum (FBS) up to 21 days. The MSCs were cultivated in basic DMEM as a control. Cell morphology was observed by microscope. Cell proliferation was tested by using the fluorescent dye SYBR green I measurement. Osteoblastic differentiation was evaluated by alkaline phosphatase (ALP) histochemical staining, quantitative calcium deposit, and real-time PCR technology. Results Characterization of primary MSCs: At day 1, most cells depicted round and floating hematopoietic cells. Colonies consisting of fibroblastlike cells were observed at day 3 after removal of nonadherent cells, colonies grew to various sizes at day 7. Thirteen population doublings took place in primary culture. Osteoblastic differentiation: During osteogenic stimulation, cellular morphology of MSCs changed from a fibroblastic shape to a cubical form. Cell proliferation had no impact in osteogenic medium compared to basic medium (Pgt;0.05). At day 14, ALP staining presented b positive. Calcium deposit pronouncedly increased at day 21 (Plt;001). Furthermore, the mRNA levels of core binding factor α1 (Cbfα1), osterix, ALP, collagen Ⅰ(ColⅠ), osteonectin (ON) and osteocalcin (OC) increased gradually. Cbfα1, ON and ALP genes increased at early stage of osteoblastic differentiation. Osterix and OC at day 21 were significantly increased when compared with that at day 7 (Plt;0.05). ColⅠ was increased at day 14 (Plt;0.05). Conclusion Porcine MSCs harvested from bone marrow by density gradient centrifugation are capable of osteoblastic differentiation in vitro. The potential of osteoblastic differentiation relies upon upregulation of genes specific to this lineage under the osteogenic conditions.
Objective To review the progress, controversy and trend in the regulation and mechanism of the microRNAs (miRNAs) during the osteogenesis. Methods Recent l iterature concerning regulation and mechanism of the miRNAs during the osteogenesis was extensively reviewed, summarized and analyzed. Results Recently miRNAs was a hot topic for osteogenesis. More and more materials showed its important role in ossification, but its definite mechanism was notclear. Conclusion Osteogenesis can be strengthened by miRNAs technology, which has a bright future and may also provide the molecular mechanism. The study on miRNAs of osteogenesis can provide a model to analyze and compare the osteogenetic effects of novel drugs.