Induction of osteogenesis by bovine platelet transforming growth factor-beta (TGF-beta) in adult mouse femur.

TGF-beta has been shown to be one of the most important regulators in chondrogenesis and osteogenesis. Daily subperiosteal injection of TGF-beta, which was extracted and purified from bovine platelets, into adult mouse femur resulted in proliferation and differentiation of the mesenchymal cells, chondrogenesis, and endochondral osteogenesis. After cessation of the injection, the endochondral ossification occurred widely, resulting in replacement of the cartilage with new bone. These phenomena demonstrate that exogenous TGF-beta stimulates mesenchymal proliferation and differentiation that occur in early fracture healing and suggest the possibility of clinical application of TGF-beta for fracture repair and bone transplantation.

     

ROLE OF TRANSFORMING GROWTH FACTOR β （TGF-β）IN REPAIRING OF BONE DEFECTS

TGF-β is a multifunctlonal cytoklne that regulates many aspects of cellular function, including periosteal mesenchymal cell proliferation, differontlation. This experiment is to study its effects on bone defect repair. A rabbit radial bone defect model was used to evaluate the effect of TGF-β, which was extracted and purified from bovine blood platelets, on the healing of a large segmental osteoperiosteal defect. A1.5-centinaeter segmental defect was created in the mid upper part of the radial shaft of adult rabbits. The defect was filled with implant containing TGF-β that consisted of carrier and bovine TGF-β Limbs servedas controls received carrier alone. The defects were examined radiographically and histologically at 4, 8,12, 16 and 20 weeks after implantation. The results showed that in TGF-β implant group, the defect areasat 12 weeks post operation were bridged by uniform new bone and the cut ends of cortex could not be seen Fwhile in control group, the defects remained clear. Only a sraall amount of new bone formed as a cap onthe cut bone ends. In the experimental group, new lamellar and woven bone formed in continuity with thecut ends of the cortex. An entirely raedullar canal appears to be forming and contained normal-appearanclng marrow elements； while the control group displayed entirely fibrous tissue within the defect site. Remnants of the cancellous bone carrier were observed in the control specimen. These data demonstrate that exogenous TGF-β initiate osteogenesis and stimulate the bone defects repair in animal model.     

AN IMMUNOCYTOCHEMICAL STUDY OF BONEMORPHOGENETIC PROTEIN IN EXPERIMENTAL FRACTURE HEALING OF THE RABBIT MANDIBLE

A monoclonal antibody raised against bone morphogenetic protein (BMP-McAb)has been used to demonstrate the presence of bone mrphogenetic protein(BMP) in experimental fracture healing.Rabbit mandibles were frac-tured using standrdized methods and left to heal for 3,7,14,21and 24 d,respectively.The avidin-biotin com- plex(ABC)method demonstrated an accumulation of positively stained primitive mesenchyman cells at the fracture site in the hematoma stage of bone repair.These cells appeared to undergo differentiation into positively-stained chondroblasts and osteoblasts during the phase of callus formation.Undifferentiated mesenchymal cells showed a high positive reactivity in the early post-fracture stages but a much lower reactivity during the remodelling phase.The results of our study suggest that bone inductive processes are accompanied by the presence of BMP in osteopro-genitor cells during fracture healing of the mandible and that BMP may plqy a significant role in osteogenesis dur-ing bone healing.     

Chondrogenic differentiation of rabbit bone marrow-derived mesenchymal stem cells in vitro by aggregate culture

Objective To investigate the potential of application of a culture system that facilitates the chondrogenic differentiation of rabbit bone marrow-derived mesenchymal stem cells （MSCs）. Methods Cells obtained in bone marrow aspirates were isolated by monolayer culture from 4 rabbits and transferred into tubes and allowed to form three-dimensional aggregates in a chemically defined medium inclusion TGF-β1.     

Effect of rhBMP-2 and Osteogenic Revulsants on Proliferation and Differentiation of Bone Marrow Stromal Cells in Rats

The effects of recombinant human bone morphogenetic protein-2 （rhBMP-2） and osteogenic revulsants alone or in combination at different time points and in different dosages on proliferation and osteogenesis of bone marrow stromal cells （BMSCs） in SD rats were investigated. Rat BMSCs were cultured in vitro and induced by rhBMP-2 in different dosages （10, 50, 100 and 200μg/L） alone or in combination with osteogenic revulsants. MTT colorimetric assay was used to evaluate The proliferation, activity of alkaline phosphoric （ALP） and osteocalcin were measured at 3rd, 6th, 9th, 12th day respectively. The results showed that rhBMP-2 and osteogenic revulsants could promote the differentiation of BMSCs towards osteoblast phenotype. The proliferation of BMSCs could be enhanced by rhBMP-2 in a dose-dependent manner. The expression of osteoblast phenotype was significantly higher by using both of them than by using them alone, which was verified by the activity of ALP and osteocalcin. It was suggested that the combined use of rhBMP-2 and osteogenic revulsants could promote the proliferation and simultaneously induce and maintain the expression of osteoblast phenotype of BMSCs in rats.     

Electromagnetic Field Change the Expression of Osteogenesis Genes in Murine Bone Marrow Mesenchymal Stem Cells

In order to identify the differentially expressing gene of bone marrow mesenchymal stem cells （MSCs） stimulated by electromagnetic field （EMF） with osteogenesis microarray analysis, the bone marrow MSCs of SD rats were isolated and cultured in vitro. The third-passage cells were stimulated by EMFs and total RNA was extracted, purified and then used for the synthesis of cDNA and cRNA. The cRNA of stimulated group and the control group was hybridized with the rat oligo osteogenesis microarray respectively. The hybridization signals were acquired by using X-ray film after chemiluminescent detection and the data obtained were analyzed by employing the web-based completely integrated GEArray Expression Analysis Suite. RT-PCR was used to identify the target genes： Bmp1, Bmp7, Egf and Egfr. The results showed that 19 differentially expressing genes were found between the stimulated group and the control group. There were 6 up-regulated genes and 13 down-regulated genes in the stimulated group. Semi-quantitative RT-PCR confirmed that the expressions of Bmpl, Bmp7 mRNA of the stimulated group were up-regulated （P〈0.05） and those of Egf, Egfr were down-regulated （P〈0.05）. It was suggested that the gene expression profiles of osteogenesis of the bone marrow MSCs were changed after EMF treatment. It is concluded that the genes are involved in skeletal development, bone mineral metabolism, cell growth and differentiation, cell adhesion etc.     

Wild-type Smad3 Gene Enhances the Osteoblastic Differentiation of Rat Bone Marrow-derived Mesenchymal Stem Cells in Vitro

This study examined the effect of wild-type Smad3 gene on the osteoblastic differentiation of rat bone marrow-derived mesenchymal stem cells in vitro. Bone marrow-derived mesenchymal stem cells （MSCs） were stably transfected with the complexes of PeDNA3.0-Myc-Smad3 or PeDNA3.0- Mye-Smad3△C and Lipofectamine reagent. Immunofluorescence staining was performed to evaluate the c- Myc signal in MSCs. The cell proliferation was detected by MTT method. To clarify the osteoblastic characteristics in stably transfected MSCs, alkaline phosphatase （ALP） mRNA and core binding factor α1 （Cbfal） mRNA were investigated by RT-PCR, and ALP activity and mineralization were examined by p-nitrophenolphosphate method and alizarin red staining respectively. PD98059, a specific inhibitor of the ERK signaling pathway, was used to determine the role of ERK in Smad3MSCs osteoblastic differentiation, c-Myc signal was detected in Smad3-MSCs and Smad3△C- MSCs. The proliferation of Smad3-MSCs was slower than that of Smad3/△C-MSCs or V-MSCs. The relative levels of ALP mRNA and Chfal mRNA in Smad3-MSCs, as well as ALP activity and mineralization, were markedly higher than those in Smad3/△C-MSCs or V-MSCs. Although ALP activity and mineralization were slightly lower in Smad3-MSCs.treated with PD98059 than in those without PD98059 treatment, no significant difference was found between them （P〉0.05）. It is concluded that the wild-type Smad3 gene, which is a crucial component promoting bone formation, can inhibit the proliferation of MSCs and enhance the osteoblastic differentiation of uncommitted MSCs and the maturation of committed MSCs independent of the ERK signaling pathway.     

RADIOAUTOGRAPHIC STUDY OF EXPERIMENTAL FRACTURE HEALING

Following fracture of left tibia in 14 Wistar rats the mitosis and proliferation of various cellular components in callus tissues were studied with ~3H-Thymidine labelling and radioautographic technique. There was accumulation of silver grains over the nuclei of mesenchymal cells ,endothelial cells of capillaries, fibroblasts and chondrocytes as a result of mitosis and incorporation of the labelling isotopes. Although the osteoblasts and osteocytes could not divide they derived from the mesenchymal cells and osteogenic cells, thus showing silver grains as well. Besides, fat cells and muscle cells likewise revealed silver grains signifying that in fracture healing a number of connective tissue cells underwent mitosis and proliferation.     

Evaluation of CD24 as a marker to rapidly define the mesenchymal stem cell phenotype and its differentiation in human nucleus pulposus

Background Recent studies have indicated that human nucleus pulposus contain mesenchymal stem cells （NP-MSCs）. However, the immunophenotypic variation of NP-MSCs in vitro was unclear. The present study was conducted to address the immunophenotypic variation of mesenchymal stem cells in nucleus pulposus under continuous proliferation in vitro and show the difference between mesenchymal stem cells and nucleus pulposus cell. Methods Tissue samples were obtained from thoracolumbar burst fracture patients and degenerative disc disease patients who underwent discectomy and fusion procedures. Flow cytometric and laser scanning confocal microscope （LSCM） were used to detect the variation of mesenchymal stem cells in nucleus pulposus which were expressing CD105 and CD24 in condition with or without transforming growth factor [31 （TGF-131）. Results More than 90% of the analyzed primary cells of mesenchymal stem cells in nucleus pulposus fulfilled the general immunophenotyping criteria for MSCs, such as CD44, CD105 and CD29, but the marker of mature NP cells characterized as CD24 was negative. In continuous cultures, the proportion of mesenchymal stem cells which were expressing CD44, CD105 and CD29 in nucleus pulposus gradually decreased. The mesenchymal stem cells in nucleus pulposus cells were positive for CD105 and CD29, with slight positivity for CD44. The CD24 expression gradually increased in proliferation. Bi- parametric flow cytometry and laser scanning confocal microscopy confirmed the presence of cells which were expressing CD105 and CD24 independently, and only a small part of cells expressed both CD105 and CD24 simultaneously. TGF-{31 could stimulate mesenchymal stem cells in nucleus pulposus to express CD24. Conclusions Non-degenerative and degenerative NP contains mesechymal stem cells. The variation of CD24 can be used as a marker to identify the NP-MSCs differentiation into NP-like cells.     

Influence of bone morphogenetic proteins-2 and strontium chloride on the human umbilical cord mesenchymal stem cells proliferation and osteogenic differentiation

<正>Objective To study the effects of combination of bone morphogenetic protein-2 (BMP-2) and strontium chloride on proliferation and osteogenic differentiation of human umbilical cord mesenchymal stem cells(hUCM-SCs)in vitro culture.     

Effects of emodin on the proliferation of the glomerular mesangial cell and correlative cytokines in rats

Objective：To investigate the effects of emodin（EMD） on cell proliferation and correlative cytokines secretion of glomerular mesangial in rats. Methods：The effects of EMD on cell proliferation and IL-6, TGF-β1 secretion of glomerular mesangial in rats were observed. Cell proliferation was measured by MTT method. IL-6 and TGF-β1 secretion was detected with ELISA. Results：EMD was able to inhibit the cell proliferation and down-regulate the IL-6 and TGF-β 1 secretion of glomerular mesangial, as compared to the model group in rats （P 〈 0.05）. Conclusion：EMD could significantly inhibit the cell proliferation, and reduce the creation of extracellular matrix（ECM）, this indicated that it could play an important role in alleviation and prevention of glomerular sclerosis. The mechanism may be that EMD can reduce the IL-6 and TGF-β1 secretion ofglomerular mesangial cell in rats.     

Combined Use of RGD-peptide Modified PLGA and TGF-β1 Gene Transfected MSCs to Improve Cell Biobehaviors in vitro

In order to improve the surface properties of PLGA polymer for a better material/cell interface to modulate the cells behaviors, we prepared a novel three-block copolymer, PLGA-[ASP-PEG], and immobilized an RGD-containing peptide, Gly-Arg-Gly-Asp-Ser-Pro-Cys （GRGDSPC） on the surface of it. Transforming growth factor-β1 （TGF-β1） was transfected into bone marrow stromal cells （MSCs） employed as seeded cells. Cell adhesion, spreading, proliferation and differentiation on this material were investigated. The results showed that the cell adhesive ratio on RGD-modified materials was higher than on un-modified materials （P〈0.05）. The extent of cell spreading was also wider on RGD-modified materials than on un-modified materials. Cell proliferation indices of transfected MSCs were increased as compared with the un-transfected MSCs （P〈0.05）. The ALP activities in the MSCs cultured with RGD-modified materials were higher than on un-modified materials after 14 days （P〈0.05）, and those in transfected MSCs were higher than in un-transfected MSCs （P〈0.05）. It was suggested that the combined use of RGD-modification and TGF-β gene transfection could improve the interaction of biomaterial and cells.     

Histological changes after tibial lengthening with metaphyseal osteotomy in goats

The histological changes after tibial lengthening with metaphyseal osteotomywere observed in 30 goats.It was found that(1)a slow lengthening rate of 1 mm/d couldenable the tissues to adapt the mechanical traction and consequently increase thelengthening limitation;(2)the newly-formed bone in the lengthened area might be due to acombined osteogenesis of endochondral,intramembranous,and fibrous tissue ossification;and(3)the osteogenetic process could be distinguished into 3 stages as hemorrhage andorganization of the hematocele,callus formation,and remodelling of the newly-formedbones.     

The Development of Bone Marrow Mesenchymal Stem Cells Culture in vitro

Objective To review the development of bone marrow mesenchymal stem cells culture in vitro. Data sources The data cited in this review were mainly obtained from the articles listed in Medline and PubMed. The search terms were “bone marrow mesenchymal stem cell” and “cell culture”. Study selection Articles regarding the development of BM-MSCs culture in vitro, as well as the challenge of optimizing cell culture environment in 2D vs 3D. Results Improving the culture conditions increase the proliferation and reduce the differentiation. Optimal values for many culture parameters remain to be identified.Expansion of BM-MSCs under defined conditions remains challenges, including the development of optimal culture conditions for BMSC and large-volume production systems.     

Chondrogenic Differentiation of Mouse Bone Marrow Mesenchymal Stem Cells Induced by Cartilage-derived Morphogenetic Protein-2 In Vitro

To study the cartilage differentiation of mouse mesenchymal stem cells （MSCs） induced by cartilage-derived morphogenetic proteins-2 in vitro, the MSCs were isolated from mouse bone marrow and cultured in vitro. The cells in passage 3 were induced into chondrogenic differentiation with different concentrations of recombinant human cartilage-derived morphogenetic proteins-2 （0, 10, 20, 50 and 100 ng/mL）. After 14 days of induction, morphology of cells was observed under phase-contrast microscope. Collagen Ⅱ mRNA and protein were examined with RT-PCR, Western blotting and immunocytochemistry respectively and the sulfate glycosaminoglycan was measured by Alcian blue staining. RT-PCR showed that CDMP-2 could promote expression of collagen Ⅱ mRNA in an dose-dependant manner, especially at the concentration of 50 ng/mL and 100 ng/mL. Immunocytochemistry and Western blotting revealed a similar change. Alcian blue staining exhibited deposition of typical cartilage extracellular matrix. Our results suggest that mouse bone marrow mesencymal stem cells can differentiate into chondrogenic phonotype with the induction of CDMP-2 in vitro, which provides a basis for further research on the role of CDMP-2 in chondrogenesis.     

Analysis of transforming growth factor β signaling in chronic rhinosinusitis

Background It has been reported that there is a significant difference in the local tissue concentration of transforming growth factor （TGF）-β1 between chronic rhinosinusitis without nasal polyps （CRSsNP） and chronic rhinosinusitis without nasal polyps （CRSwNP） patients. TGF-β has been reported to play an important role in regulating epithelial cell repair in lower airway remodeling and may be a critical factor involved in the remodeling process of chronic rhinosinusitis （CRS）. Methods Ethmoidal mucosal samples collected from CRS and healthy control patients were analyzed for TGF-β1, TGF-β receptor I, TGF-βreceptor II, Smad3, phospho-Smad3, Smad7, and Smad anchor for receptor activation by Western blotting analysis. The proliferation of sinonasal epithelial cells at baseline and after TGF-β1 and/or EGF stimulation was evaluated by the MTT assay. Results In CRSsNP, TGF-β1, TGF-β receptor I, TGF-β receptor II, and Smad3 protein levels were significantly higher than controls. In CRSwNP, TGF-β1, Smad3, and pSmad3 protein levels were significantly lower than controls. Smad7 protein was significantly higher in CRS than controls. In vitro experiments demonstrated that the baseline proliferation levels of sinonasal epithelial cells were lower in CRS than controls. Conclusions CRSwNP is characterized by a lower level of TGF-signaling compared with the control, In CRSsNP, although the upstream signaling of TGF-β was enhanced, the high Smad7 protein expression may restrain the downstream signaling components （e.g., pSmad3） and the TGF-β antiproliferative effect on sinonasal epithelium. The difference in the local tissue concentration of TGF-β1 between CRSsNP and CRSwNP patients did not result in significant differences in epithelial proliferation.     

Mechanisms simultaneously regulate smooth muscle proliferation and differentiation

Vascular smooth muscle cell （VSMC） differentiation and proliferation are two important physiological proc- esses during vascular development. The phenotypic alteration from differentiated to proliferative VSMC contrib- utes to the development of several major cardiovascular diseases including atherosclerosis, hypertension, resteno- sis after angioplasty or bypass, diabetic vascular complications, and transplantation arteriopathy. Since the VSMC phenotype in these pathological conditions resembles that of developing VSMC during embryonic development, understanding of the molecular mechanisms that control VSMC differentiation will provide fundamental insights into the pathological processes of these cardiovascular diseases. Although VSMC differentiation is usually ac- companied by an irreversible cell cycle exit, VSMC proliferation and differentiation occur concurrently during embryonic development. The molecular mechanisms simultaneously regulating these two processes, however, remain largely unknown. Our recent study demonstrates that cell division cycle 7, a key regulator of cell cycle, promotes both VSMC differentiation and proliferation through different mechanisms during the initial phase of VSMC differentiation. Conversely, Kriappel-like factor 4 appears to be a repressor for both VSMC differentia- tion and proliferation. This review attempts to highlight the novel role of cell division cycle 7 in TGF-β-induced VSMC differentiation and proliferation. The role of K141ppel-like factor 4 in suppressing these two processes will also be discussed.     

Hippophae rhamnoides L. leaves extract enhances cell proliferation and neuroblast differentiation through upregulation of intrinsic factors in the dentate gyrus of the aged gerbil

Background Hippophae rhamnoides L.（HL） exerts antioxidant activities against various oxidative stress conditions.In this study,we investigated effects of extract from HL leaves （HLE） on cell proliferation and neuroblast differentiation in the subgranular zone （SGZ） of the dentate gyrus （DG） of aged gerbils.Methods Aged gerbils （24 months） were divided into vehicle （saline）-treated-and HLE-treated-groups.The vehicle and HLE were orally administered with 200 mg/kg once a day for 20 days before sacrifice.Cell proliferation and neurobiast differentiation were examined in the DG using Ki67 and doublecortin （DCX）,respectively.We also observed changes in immunoreactivities of superoxide dismutase 1 （SOD1） and superoxide dismutase 2 （SOD2）,brain-derived neurotrophic factor （BDNF）,and phospho-glycogen synthase kinase-3-beta （p-GSK-3β） to examine their relation with neurogenesis using immunohistochemistry.Results The administration of HLE significantly increased the number of Ki67-positive cells and DCX-positive neuroblasts with well-developed processes in the SGZ of the DG of the HLE-treated-group.In addition,immunoreactivities of SOD1,SOD2,BDNF,and p-GSK-3β were significantly increased in granule and polymorphic cells of the DG in the HLE-treated-group compared with those in the vehicle-treated-group.Conclusions HLE treatment significantly increased cell proliferation and neuroblast differentiation,showing that immunoreactivities of SOD1,SOD2,BDNF,and p-GSK-3β were significantly increased in the DG.These indicate that increased neuroblast differentiation neurogenesis may be closely related to upregulation of SOD1,SOD2,BDNF,and p-GSK-3β in aged gerbils.     

Expression of OPGmRNA and ODFmRNA in the patients of hip fracture due to osteoporosis

Objective：To investigate the gene expression of osteoprotegerin（OPG） and osteoclast differentiation factor（ODF） in the bone tissue of patients with hip fracture due to osteoporosis. Methods：OPGmRNA and ODFmRNA in the bone tissue in 50 cases of osteoporosis sufferers（over 50 years old） with hip fracture（Observer Group） and 30 cases of hip facture sufferers with no osteoporosis（Control group） were analyzed with the Semi-Quantitative RT-PCR method. Results：The mRNA expressed of ODF, OPG were both high in the patients with hip fracture. In the control group, the expression of OPG mRNA was observed, while the expression of ODF mRNA was very slight. Conclusion：Aged patients contained all signals including OPG, ODF that are essential for inducing osteoclastogenesis and promoting bone resorption.