OBJECTIVE: To investigate the effects of three-dimentional culture in bioderived material modified by Pluronic F-127 on the growth and function of rabbit periosteal osteoblast in vitro. METHODS: Bio-derived materials were from fresh pig ribs and were modified by Pluronic F-127. Then rabbit periosteal osteoblasts were cultured in bio-derived materials(group A), in the modified bio-derived materials(group B) and on the plastic surfaces as a control (group C), respectively. During a 7-day period, the status of growth, cell viability and alkaline phosphatase(ALP) activity were measured. RESULTS: Osteoblasts attached, elongated and grew well on the modified bio-derived materials. There were no significant difference in osteogenesis and ALP activity between group A and group B(P gt; 0.05). The osteogenesis and ALP activity in groups A, B were less than those in group C (P lt; 0.01). CONCLUSION: Pluronic F-127 can be used for a carrier for bioactive factors to modify bio-derived 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.
Objective To establish a model of the human marrow mesenchymal stem cells (hMSCs) cultured under the hypoxic condition in adults and to investigate the biological features of MSCs under hypoxia.Methods The bone marrow was obtained by aspiration at the posterior superior iliac spine in 3 healthy adult subjects. hMSCs were isolated by the gradient centrifugation and were cultured in the DMEM-LG that contained 20％ fetal bovine serum. The serial subcultivation was performed 10-14 days later. The second passage of the hMSCs were taken, and they were divided into the following 4 groups according to the oxygen concentrations and the medium types: the normoxic group（20％O2, DMEM-LG, Group A）, the hypoxic group（1％O2, DMEM-LG,Group B）, the normoxic osteoblast induction group（20％O2, conditioned medium, Group C）, and the hypoxic osteoblast induction group（1％O2, conditioned medium, Group D）. The biological features of the cultured hMSCs under hypoxia were assessed bythe cell count, the MTT method, the colony forming unit-fibroblast, the real-time RT-PCR, and the alkaline phosphatase (ALP) activity, and the alizarinred staining. Results The hMSCs cultured in the Group B and Group D had a significantly higher proliferation rate than those in the Group A (Plt;0.01), and the culture effect was not influenced by the medium type. The hMSCs in the Group B had a significantly higher level of the colony-forming unit capability than the hMSCs cultured in the Group A(Plt;0.01). After the induction, hMSCs in the Group B had a decreasednumber of the osteoblasts than hMSCs in the Group C. The hMSCs in the Group D had a gradually-increasedactivity of ALP, which was significantly lower than that in the Group C(Plt;0.01). The RT-PCR examination revealed that ALP,osteocalcin, and mRNA expressions of collagen type Ⅰ and osteonectin in the Group Csignificantly increased （P＜0.01). By comparisonamong the 3 groups, after the 4-week culture the obvious calcium salt deposit and the red-stained calcium nodus could be observed.ConclusionHypoxia can promote the proliferation rate of hMSCs, enhance the colonyforming ability and inhibit the differentiation of the osteoblasts.
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 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 sum up the clinical results of bio-derived bone transplantation in orthopedics with tissue engineering technique. METHODS: From January 2000 to May 2002, 52 cases with various types of bone defect were treated with tissue engineered bone, which was constructed in vitro by allogeneous osteoblasts from periosteum (1 x 10(6)/ml) with bio-derived bone scaffold following 3 to 7 days co-culture. Among them, there were 7 cases of bone cyst, 22 cases of non-union or malunion of old fracture, 15 cases of fresh comminuted fracture of bone defect, 4 cases of spinal fracture and posterior route spinal fusion, 3 cases of bone implant of alveolar bone, 1 case of fusion of tarsotarsal joint. The total weight of tissue engineered bone was 349 g in all the cases, averaged 6.7 g in each case. RESULTS: All the cases were followed up after operation, averaged in 18.5 months. The wound in all the case healed by first intention, but 1 case with second intention. Bone union was completed within 3 to 4.5 months in 50 cases, but 2 cases of delayed union. Six cases were performed analysis of CD3, CD4, CD8, ICAM-1 and VCAM-1 before and after operation, and no obvious abnormities were observed. CONCLUSION: Bio-derived tissue engineered bone has good osteogenesis. No obvious rejection and other complications are observed in the clinical application.
ObjectiveTo review the osteoclasts (OC) function beyond bone resorption. MethodsThe related literature on OC function beyond bone resorption was reviewed, analyzed, and summarized. ResultsOC control the bone formation through releasing of matrix-derived growth factors, bidirectional cell-to-cell signals, and secreting OC-coupling factors, and play an important role in the niche formation, hematopoietic stem cells mobilization, and maintenance of its quantity and function;besides, OCs also regulate angiogenesis. ConclusionThese discoveries greatly enrich the current knowledge of OC function and open up an all-new research domain. However, the exact regulatory mechanism of OC affecting the hematopoiesis is still lack in-depth understood. Additionally, it remains to be elucidated how OC-coupling factors act on osteoblast lineage differentiation and how OC-induced angiogenesis participates in physiological and pathological processes. Unclosing the underlying mechanisms will facilitate providing scientific therapeutic strategies for treatment of many OC-related diseases.
ObjectiveTo study the effect of titanium particles on the proliferation, differentiation, and cytomorphology of osteoblasts, and to explore the possible internal relations and mechanism. MethodsCalvarial osteoblasts were separated from 10 newborn Sprague Dawley rats by repeated enzyme digestion, and were cultured in vitro. The cells were identified by alkaline phosphatase (ALP) staining and alizarin red staining. The cells at passage 3 were cultured with titanium particles culture medium at concentrations of 0.01, 0.05, 0.1, 0.5, and 1 mg/mL (0.01, 0.05, 0.1, 0.5, and 1 mg/mL groups). The absorbance (A) values were detected by cell counting kit 8 at 7 days after cultured to compare the effect of titanium particles at different concentrations on proliferation, and median lethal concentration was screened out. The expression of collagen type I was detected by ELISA to observe the effect of titanium particles on differentiation. The osteoblasts co-cultured with titanium particles of median lethal concentration (experimental group) for 7 days, and double fluorescence staining with FITC-phalloidine and propidium iodide was performed. The cytomorphology variation of osteoblasts after swallowing titanium particles was observed under laser scanning confocal microscope. The osteoblasts at passage 3 cultured with culture medium without titanium particles served as control group. ResultsThe cultured cells were identified as osteoblasts by ALP staining and alizarin red staining. Different concentrations of titanium particles could inhibit osteoblasts proliferation and differentiation in varying degrees, showing significant difference when compared with the control group at 7 days after culture (P<0.05). The cell proliferation and differentiation were decreased with increased titanium particles concentration; significant differences were found between the other groups (P<0.05) except 0.01 and 0.05 mg/mL groups (P>0.05). The median lethal concentration of titanium particles was 0.5 mg/mL. Laser scanning confocal microscope showed cellular shrinking, microfilaments distortion, pseudopodia contraction of osteoblasts that swallowed titanium particles in the experimental group. ConclusionTitanium particles can inhibit proliferation and differentiation of osteoblasts. The effect may be related to variation of cytomorphology after swallowing titanium particles.
Objective To study the gene expressions of human osteoblasts during the construction of tissue engineered bone with the bioderived material. Methods The fetal osteoblasts were used to construct tissue engineered bone with the bio-derived material and then were cultured 2,4,6,8 and 10 days in vitro. Real-time PCR analysis indicated that Cbfa 1, Osterix, Collagen type Ⅰ,osteocalcin(OC) and Integrin α5 and β1 were present in osteoblasts with bio-derived materials.Results The change ofCbfa1 was consistent with the change of Osterix. On 2nd day and 8th day, the expression of Osterix in experimental group was higher than that in control group, P＜0.05. Collagen type Ⅰ’s change was consistent with change of OC expression, and its expression was higher in experimental group than that in control group on 2nd, 4th, 6th and 8th day. The Integrinexpression was high all along. Conclusion The important genes can be expressed normally by integrating osteoblasts with bioderived scaffolds. As skeleton tissue engineering scaffold, the bio-derived bone is conducive to keepthe osteoblast’s phenotype and differentiation with osteoconductive ability. The osteoblast can enter proliferation stage favorably and the scaffold materials exert no effects on it. Bio-derived bone can also supply more space for cellsto proliferate. The bio-derived materials promote osteoblasts adhesion.
Objective To study the effect of signal-selective parathyroid hormone (PTH) analogue peptide on Wnt signal ing factors in osteoblasts isolated from neonatal mouse, and provide theoretical basis for the mechanism of PTH’s function in bone metabolism. Methods Osteoblasts were isolated from calvaria of 2-3-day-old C57BL neonatal mouse and identified by alkal ine phosphatase (ALP) staining, and Alizarin red staining. The cells at passage 1 were divided into 4 groups: control group, PTH (1-34) group, G1R19 (1-34) group, and G1R19 (1-28) group. Then the medium was changed to α-MEM supplemented with 1%FBS. After 12 hours, trifluoroacetic acid or three peptides [(10 nmol/L PTH (1-34), 10 nmol/L G1R19 (1-34), and 100 nmol/L G1R19 (1-28)] were added into the culture medium. After 4 hours, the cells were washed gently ithcold PBS 3 times before total RNA was isolated. The expressions of Wnt related genes were measured by quantitative eal-time PCR. Results Most of the cells were polygonal and triangular; the cells were positive for ALP staining with blue cytoplasm at 14 days and the Al izarin red staining showed the formation of red mineral ized nodules in the special mineral ization induction medium at 28 days. The expressions of osteocalcin mRNA and Wnt5b mRNA in PTH (1-34) group, G1R19 (1-34) group, and G1R19 (1-28) group were significantly higher than those in control group (P lt; 0.05); the expression of Wnt2 mRNA was significantly lower than that in control group (P lt; 0.05); the expression of β-catenin mRNA in PTH (1-34) group was significantly higher than that in control group (P lt; 0.05); the expression of Wnt7b mRNA in PTH (1-34) group and G1R19 (1- 34) group was higher than that in control group, and the G1R19 (1-34) group was higher than PTH (1-34) group and G1R19 (1-28) group (P lt; 0.05). Conclusion In the Wnt-related factors, PTH (1-34) and G1R19 (1-34) affect mainly canonical Wnt signal factors, but the G1R19 (1-28) chiefly acts on non-canonical Wnt signal factors.