Osteogenic differentiation of mesenchymal stem cells in biodegradable sponges composed of gelatin and beta-tricalcium phosphate

Biodegradable gelatin sponges incorporating various amounts of beta-tricalcium phosphate (betaTCP) (gelatin-betaTCP) were fabricated and the in vitro osteogenic differentiation of mesenchymal stem cells (MSC) isolated from the rat bone marrow in the sponges was investigated. The gelatin sponges incorporating betaTCP have an interconnected pore structure with the average size of 180-200 microm, irrespective of the betaTCP amount. The stiffness of the sponges became higher with an increase in the amount of betaTCP. When seeded into the sponges by an agitated method, MSC were homogeneously distributed throughout the sponge. The morphology of cells attached got more spreaded with the increased betaTCP amount. The rate of MSC proliferation depended on the betaTCP amount and culture method: the higher the betaTCP amount in the stirring culture, the higher the proliferation rate. The deformed extent of gelatin-betaTCP sponges was suppressed with the increased amount of betaTCP. When measured to evaluate the osteogenic differentiation of MSC, the alkaline phosphatase activity and osteocalcin content became maximum for the sponge with a betaTCP amount of 50 wt%, although both the values were significantly high in the stirring culture compared with those in the static culture. We concluded that the attachment, proliferation, and osteogenic differentiation of MSC were influenced by sponge composition of gelatin and betaTCP as the cell scaffold.     

Magnesium calcium phosphate as a novel component enhances mechanical/physical properties of gelatin scaffold and osteogenic differentiation of bone marrow mesenchymal stem cells

Biodegradable gelatin sponges incorporating various amounts of magnesium calcium phosphate (MCP) were introduced and the in vitro osteogenic differentiation of rat bone marrow mesenchymal stem cells (MSCs) in the sponges was investigated. The MCP was added to the gelatin sponges at 0, 25, 50, 75, and 90 wt%. The pore sizes of the gelatin sponges ranged from 143 to 154.3 μm in diameter and the porosity percentage was 34.3-50.1%. The compression modulus of the sponges and the resistance to the volume change significantly increased with increases in the amount of MCP. When seeded into the sponges by an agitating method, MSCs were distributed throughout the sponges. Following the incubation of MSCs in the gelatin sponges, a significantly higher cellular proliferation and alkaline phosphatase activity was observed in the gelatin sponges incorporating higher MCP contents. On the other hand, the osteocalcin content of MSCs seeded in the gelatin sponges incorporating no or low MCP showed a significantly higher levels in comparison with the MSCs seeded in the gelatins incorporating high MCP. These findings indicate that the MCP incorporation maintained the pore size and porosity percentage of the gelatin sponges and enabled the sponge to achieve mechanical reinforcement as well as promoting MSC proliferation and osteogenic differentiation.     

Osteogenic Differentiation of Bone-Marrow-Derived Stem Cells Cultured with Mixed Gelatin and Chitooligosaccharide Scaffolds

This study investigates the effect of scaffolds prepared from gelatin (G) and chitooligosaccharide (COS) on the osteogenic differentiation of rat bone-marrow-derived mesenchymal stem cells (MSC). The sponge scaffolds at G/COS mixing ratios of 100:0, 70:30 and 50:50 were fabricated by freeze-drying, followed by glutaraldehyde cross-linking. The pore size of the G/COS scaffolds ranged from 70 to 105 μm. MSC cultured in the scaffolds in the osteogenic medium were differentiated into osteogenic cells for all G/COS scaffolds. Calcium nodules were homogeneously formed on the surface of scaffolds cultured with MSC. A Fourier transform infrared (FT-IR) analysis demonstrated the formation of hydroxyapatite spectroscopically. Among all G/COS scaffolds, the highest ALP activity and calcium content were observed for MSC cultured in the G/COS 70:30 scaffolds. The G/COS 70:30 scaffolds were then pre-cultured with MSC in the osteogenic medium for 28 days and subcutaneously implanted into nude mice to evaluate ectopic bone formation. Enhanced vascularization, cell infiltration, collagen formation and calcium deposition around the scaffolds implanted were histologically observed at 2 and 8 weeks after implantation. It was concluded that the G/COS scaffold with the mixing ratio of 70:30 was a promising organic material to induce osteogenic differentiation of MSC.     

rhBMP-2／无定形磷酸钙纳米缓释微粒成骨活性的实验研究

目的探讨无定形磷酸钙（ACP）对rhBMP-2的缓释作用，检测rhBMP-2／ACP纳米缓释微粒的成骨活性。方法用扫描电镜观察已制备rhBMP-2／ACP缓释微粒的大小、形态：测定rhBMP-2的体外释放情况并描绘曲线；用MTT法检测缓释微粒对兔骨髓间充质干细胞（MSC）增殖情况的影响：用碱性磷酸酶（ALP）试剂盒检测细胞ALP活性以反映缓释微粒对其分化的影响．并与ACP的作用进行比较；将缓释微粒植入大鼠股部肌袋．通过X线、组织形态学观察评价缓释微粒的异位成骨能力。结果缓释微粒大小为100nm左右．具有典型的无定形球形面貌。开始时为快速释放期．随后呈缓慢持续释放。缓释微粒能显著促进MSC的增殖和分化，植入大鼠股部肌袋12周．材料大部分降解．有明显的骨形成。结论ACP可作为rhBMP-2合适的缓释载体材料．生成的纳米缓释微粒具有良好的降解性能和成骨活性。     

Osteogenic differentiation of mesenchymal stem cells in self-assembled peptide-amphiphile nanofibers

The proliferation and differentiation of mesenchymal stem cells (MSC) was investigated in a three dimensional (3-D) network of nanofibers formed by self-assembly of peptide-amphiphile (PA) molecules. PA was synthesized by standard solid phase chemistry that ends with the alkylation of the NH(2) terminus of the peptide. The sequence of arginine-glycine-aspartic acid (RGD) was included in peptide design as well. A 3-D network of nanofibers was formed by mixing cell suspensions in media with dilute aqueous solution of PA. Scanning electron microscopy (SEM) observation revealed the formation of fibrous assemblies with an extremely high aspect ratio and high surface areas. When rat MSC were seeded into the PA nanofibers with or without RGD, larger number of cells attached was observed in the PA nanofibers including RGD. When measured to evaluate the osteogenic differentiation of MSC, the alkaline phosphatase (ALP) activity and osteocalcin content became maximum for the PA nanofibers including RGD compared with those without RGD, although both the values were significantly higher compared with those in the static tissue culture plate (2-D culture). We concluded that the attachment, proliferation, and osteogenic differentiation of MSC were influenced by PA nanofibers as the cell scaffold.     

Modulation of differentiation and mineralization of marrow stromal cells cultured on biomimetic hydrogels modified with Arg-Gly-Asp containing peptides

We synthesized biomimetic hydrogels modified with an osteopontin-derived peptide (ODP) and used them as a substrate for in vitro culture of marrow stromal cells (MSCs) to investigate the effect of the biomimetic surface on differentiation of MSCs into osteoblasts. Proliferation and biological assays for 16 days proved that MSCs became differentiated into osteoblasts secreting osteogenic phenotypic markers such as alkaline phosphatase (ALP), osteopontin, and mineralized calcium. In addition, there was an additive effect of the cell-binding peptide on differentiation and mineralization of MSCs cultured in the presence of soluble osteogenic supplements in cell culture media. For example, calcium content at day 16 on peptide-modified hydrogels was significantly higher than on tissue culture polystyrene. Two general trends were observed: (1) proliferation of MSCs decreased as the amount of differentiation markers increased, and (2) higher peptide concentrations accelerated the differentiation of MSCs. On the hydrogel modified with ODP, ALP activity exhibited a maximum value of 36.7 +/- 4.2 pmol/cell/h at day 10 for the concentration of 2 micromol/g while the culture time needed for maximum ALP activity occurred on day 13 for the lower concentrations. On the same hydrogel, the calcium content at day 10 was 21.4 +/- 2.3 ng/cell for the peptide concentration of 2 micromol/g and 1.0 +/- 0.3 ng/cell for 1.0 micromol/g. We used Gly-Arg-Gly-Asp-Ser (GRGDS) for modification of the hydrogel as a comparison to the results with ODP. However, osteoblast development was not significantly affected by the nature of the binding peptide sequences. These results suggest that MSC function can be modulated by variation of the peptide concentration in biomimetic hydrogels used for scaffold-based bone tissue engineering.     

The effect of photopolymerization on stem cells embedded in hydrogels

Photopolymerizable hydrogels, formed by UV-exposure of photosensitive polymers in the presence of photoinitiators, are widely used materials in tissue engineering research employed for cellular entrapment and patterning. During photopolymerization, the entrapped cells are directly exposed to polymer and photoinitiator molecules. To develop strategies that prevent potential photoexposure-damage to osteoprogenitor cells, it is important to further characterize the effects of photopolymerization on the exposed cells. In this study we analyzed the viability, proliferation and osteogenic differentiation of multipotent stromal cell (MSC) monolayers after exposure to UV-light in the presence of Irgacure 2959, a frequently used photoinitiator in tissue engineering research. Cell cycle progression, apoptosis and osteogenic differentiation of encapsulated goat MSCs were studied in photopolymerized methacrylate-derivatized hyaluronic acid hydrogel and methacrylated hyperbranched polyglycerol gel. We demonstrate adverse effects of photopolymerization on viability, proliferation and reentry into the cell cycle of the exposed cells in monolayers, whereas the MSCs retain the ability to differentiate towards the osteogenic lineage. We further show that upon encapsulation in photopolymerizable hydrogels the viability of the embedded cells is unaffected by the photopolymerization conditions, while osteogenic differentiation depends on the type of hydrogel used.     

Human embryonic stem cell encapsulation in alginate microbeads in macroporous calcium phosphate cement for bone tissue engineering

Human embryonic stem cells (hESC) are promising for use in regenerative medicine applications because of their strong proliferative ability and multilineage differentiation capability. To date there have been no reports on hESC seeding with calcium phosphate cement (CPC). The objective of this study was to investigate hESC-derived mesenchymal stem cell (hESCd-MSC) encapsulation in hydrogel microbeads in macroporous CPC for bone tissue engineering. hESC were cultured to form embryoid bodies (EB), and the MSC were then migrated out of the EB. hESCd-MSC had surface markers characteristic of MSC, with positive alkaline phosphatase (ALP) staining when cultured in osteogenic medium. hESCd-MSC were encapsulated in alginate at a density of 1millioncellsml(-1), with an average microbead size of 207μm. CPC contained mannitol porogen to create a porosity of 64% and 218-μm macropores, with 20% absorbable fibers for additional porosity when the fibers degrade. hESCd-MSC encapsulated in microbeads in CPC had good viability from 1 to 21days. ALP gene expression at 21days was 25-fold that at 1day. Osteocalcin (OC) at 21days was two orders of magnitude of that at 1day. ALP activity in colorimetric p-nitrophenyl phosphate assay at 21days was fivefold that at 1day. Mineral synthesis by the encapsulated hESCd-MSC at 21days was sevenfold that at 1day. Potential benefits of the CPC-stem cell paste include injectability, intimate adaptation to complex-shaped bone defects, ease in contouring to achieve esthetics in maxillofacial repairs, and in situ setting ability. In conclusion, hESCd-MSC were encapsulated in alginate microbeads in macroporous CPC, showing good cell viability, osteogenic differentiation and mineral synthesis for the first time. The hESCd-MSC-encapsulating macroporous CPC construct is promising for bone regeneration in a wide range of orthopedic and maxillofacial applications.     

Enhanced proliferation and osteogenic differentiation of rat mesenchymal stem cells in collagen sponge reinforced with different poly(ethylene terephthalate) fibers

The objective of this study was to investigate the feasibility of collagen sponges mechanically reinforced by the incorporation of poly(ethylene terephthalate) (PET) fibers in stem cell culture. A collagen solution with homogeneously dispersed PET fibers was freeze-dried, followed by dehydrothermal cross-linking to obtain the collagen sponge incorporating PET fibers. By scanning electron microscopy observation, the collagen sponges exhibited isotropic and interconnected pore structures with an average size of 200 microm, irrespective of PET fiber incorporation. As expected, PET fibers incorporation significantly enhanced the compression strength of collagen sponge. When used for rat mesenchymal stem cells (MSC), the collagen sponge incorporating PET fibers was superior to the original collagen sponge without PET fibers incorporation in terms of the initial attachment, proliferation and osteogenic differentiation of cells, irrespective of the amount and diameter of fibers incorporated. The shrinkage of sponges during cell culture was significantly suppressed by the fiber incorporation. It is possible that the shrinkage suppression maintains the three-dimensional inner pore structure of collagen sponges without impairing the cell compatibility, resulting in the superior MSC attachment and the subsequent osteogenic differentiation in the sponge incorporating PET fiber.     

Enhanced osteogenic activity of bone morphogenetic protein-2 by 2-O-desulfated heparin

The objective of this study was to investigate the effect of heparin sulfate groups on the osteogenic activity of bone morphogenetic protein-2 (BMP-2) in vitro and in vivo. Three types of desulfated (DS) derivatives of heparin (2-O-DS, 6-O-DS, and N-DS) were prepared and their bioactivity in rat bone marrow derived mesenchymal stem cells (MSC) in the absence or presence of BMP-2 was evaluated. When cultured with the 2-O-DS derivative and BMP-2 MSC showed enhanced proliferation, alkaline phosphatase activity, and Runx2 mRNA expression, compared with heparin and other derivatives. A similar tendency was observed for MSC cultured on two-dimensional substrates coated with heparin or the derivatives and in three-dimensional hydrogels containing heparin or the derivatives. A binding experiment demonstrated a greater binding affinity of 2-O-DS for BMP-2 than that of heparin and the other derivatives. Following implantation into the back subcutis of mice significantly greater ectopic bone formation in terms of bone weight, amount of calcium, and histology were observed for the gelatin hydrogels incorporating 2-O-DS and containing BMP-2. In addition, the gelatin hydrogels incorporating 2-O-DS showed controlled release of BMP-2 in vitro and in vivo. These findings demonstrated that the 2-O-DS derivative of heparin has a synergistic effect on the in vitro and in vivo osteogenic activity of BMP-2.     

Effect of the fiber diameter and porosity of non-woven PET fabrics on the osteogenic differentiation of mesenchymal stem cells

The proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) was investigated in three-dimensional non-woven fabrics prepared from polyethylene terephthalate (PET) fiber with different diameters. When seeded into the fabrics of cell scaffold, more MSC attached in the fabric of thicker PET fibers than that of thinner ones, irrespective of the fabric porosity. The morphology of cells attached became more spreaded with an increase in the fiber diameter of fabrics. The rate of MSC proliferation depended on the PET fiber diameter and porosity of fabrics: the bigger the fiber diameter of fabrics with higher porosity, the higher their proliferation rate. When the alkaline phosphatase (ALP) activity and osteocalcin content of MSC cultured in different types of fabrics was measured to evaluate the ostegenic differentiation, they became maximum for the non-woven fabrics with a fiber diameter of 9.0 microm, although the values of low-porous fabrics were significantly high compared with those of high porous fabrics. We concluded that the attachment, proliferation and bone differentiation of MSC was influenced by the fiber diameter and porosity of non-woven fabrics as the scaffold.     

Effects of TGF-β3 and preculture period of osteogenic cells on the chondrogenic differentiation of rabbit marrow mesenchymal stem cells encapsulated in a bilayered hydrogel composite

In this work, injectable, biodegradable hydrogel composites of crosslinked oligo(poly(ethylene glycol) fumarate) and gelatin microparticles (MPs) were used to fabricate a bilayered osteochondral construct. Rabbit marrow mesenchymal stem cells (MSCs) were encapsulated with transforming growth factor-β3 (TGF-β3)-loaded MPs in the chondrogenic layer and cocultured with cells of different periods of osteogenic preculture (0, 3, 6 and 12 days) in the osteogenic layer to investigate the effects of TGF-β3 delivery and coculture on the proliferation and differentiation of cells in both layers. The results showed that, in the chondrogenic layer, TGF-β3 significantly stimulated chondrogenic differentiation of MSCs. In addition, cells of various osteogenic preculture periods in the osteogenic layer, along with TGF-β3, enhanced gene expression for MSC chondrogenic markers to different extents. In the osteogenic layer, cells maintained their alkaline phosphatase activity during the coculture; however, mineralization was delayed by the presence of TGF-β3. Overall, this study demonstrated the fabrication of bilayered hydrogel composites which mimic the structure and function of osteochondral tissue, along with the application of these composites as cell and growth factor carriers, while illustrating that encapsulated cells of different degrees of osteogenic differentiation can significantly influence the chondrogenic differentiation of cocultured progenitor cells in both the presence and absence of chondrogenic growth factors.     

In vitro osteogenic differentiation of marrow stromal cells encapsulated in biodegradable hydrogels

Novel hydrogel materials based on oligo(poly(ethylene glycol) fumarate) (OPF) crosslinked with a redox radical initiation system were recently developed in our laboratory as injectable cell carriers for orthopedic tissue engineering applications. The effect of OPF hydrogel material properties on in vitro osteogenic differentiation of encapsulated rat marrow stromal cells (MSCs) with and without the presence of osteogenic supplements (dexamethasone) was investigated. Two OPF formulations that resulted in hydrogels with different swelling properties were used to encapsulate rat MSCs (seeding density approximately 13 million cells/mL, samples 6 mm diameter x 0.5 mm thick before swelling) and osteogenic differentiation in these constructs over 28 days in vitro was determined via histology and biochemical assays for alkaline phosphatase, osteopontin and calcium. Evidence of MSC differentiation was apparent over the culture period for samples without dexamethasone, but there was large variability in calcium production between constructs using cells of the same source. Differentiation was also seen in samples cultured with osteogenic supplements, but calcium deposition varied depending on the source pool of MSCs. By day 28, osteopontin and calcium results suggested that, in the presence of dexamethasone, OPF hydrogels with greater swelling promoted embedded MSC differentiation over those that swelled less (43.7 +/- 16.5 microg calcium/sample and 16.4 +/- 2.8 microg calcium/sample, respectively). In histological sections, mineralized areas were apparent in all sample types many microns away from the cells. These experiments indicate that OPF hydrogels are promising materials for use as injectable MSC carriers and that hydrogel swelling properties can influence osteogenic differentiation of encapsulated progenitor cells.     

Evaluation of bone marrow-derived mesenchymal stem cells after cryopreservation and hypothermic storage in clinically safe medium

Achievements in tissue engineering using mesenchymal stem cells (MSC) demand a clinically acceptable "off-the-shelf" cell therapy product. Efficacy of cryopreservation of human bone marrow-derived MSC in clinically safe, animal product-free medium containing 2%, 5%, and 10% dimethyl sulfoxide (DMSO) was evaluated by measuring cell recovery, viability, apoptosis, proliferation rate, expression of a broad panel of MSC markers, and osteogenic differentiation. Rate-controlled freezing in CryoStor media was performed in a programmable cell freezer. About 95% of frozen cells were recovered as live cells after freezing in CryoStor solutions with 5% and 10% DMSO followed by storage in liquid nitrogen for 1 month. Cell recovery after 5 months storage was 72% and 80% for 5% and 10% DMSO, respectively. Measurements of caspase 3 activity demonstrated that 15.5% and 12.8% of cells after 1 month and 18.3% and 12.9% of cells after 5 months storage in 5% and 10% DMSO, respectively, were apoptotic. Proliferation of MSC recovered after cryopreservation was measured during 2 weeks post-plating. Proliferation rate was not compromised and was even enhanced. Cryopreservation did not alter expression of MSC markers. Quantitative analysis of alkaline phosphatase (ALP) activity, ALP surface expression and Ca?? deposition in previously cryopreserved MSC and then differentiated for 3 weeks in osteogenic medium demonstrated the same degree of osteogenic differentiation as in unfrozen parallel cultures. Cell viability and functional parameters were analyzed in MSC after short-term storage at 4°C in HypoThermosol-FRS solution, also free of animal products. Hypothermic storage for 2 and 4 days resulted in about 100% and 85% cell recovery, respectively, less than 10% of apoptotic cells, and normal proliferation, marker expression, and osteogenic potential. Overall, our results demonstrate that human MSC could be successfully cryopreserved for banking and clinical applications and delivered to the bedside in clinically safe protective reagents.     

Effect of the fiber diameter and porosity of non-woven PET fabrics on the osteogenic differentiation of mesenchymal stem cells

The proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) was investigated in three-dimensional non-woven fabrics prepared from polyethylene terephthalate (PET) fiber with different diameters. When seeded into the fabrics of cell scaffold, more MSC attached in the fabric of thicker PET fibers than that of thinner ones, irrespective of the fabric porosity. The morphology of cells attached became more spreaded with an increase in the fiber diameter of fabrics. The rate of MSC proliferation depended on the PET fiber diameter and porosity of fabrics: the bigger the fiber diameter of fabrics with higher porosity, the higher their proliferation rate. When the alkaline phosphatase (ALP) activity and osteocalcin content of MSC cultured in different types of fabrics was measured to evaluate the ostegenic differentiation, they became maximum for the non-woven fabrics with a fiber diameter of 9.0 μm, although the values of low-porous fabrics were significantly high compared with those of high porous fabrics. We concluded that the attachment, proliferation and bone differentiation of MSC was influenced by the fiber diameter and porosity of non-woven fabrics as the scaffold.     

Conditioned Media Enhance Osteogenic Differentiation on Poly(L-lactide-co-ε-caprolactone)/Hydroxyapatite Scaffolds and Chondrogenic Differentiation in Alginate

The biochemical factors that regulate cell proliferation and differentiation can provide a means of optimizing culture conditions to develop a tissue-engineered osteochondral construct. Thus, the objectives of this study were to determine the effects of chondrocyte conditioned medium (CM) on the osteogenic differentiation of mesenchymal stem cells (MSCs) cultured on poly(L-lactide-co-ε-caprolactone)/hydroxyapatite (PLA/PCL/HAP) scaffolds and to determine the effect of osteoblast CM on the chondrogenic differentiation of MSCs cultured in alginate. In addition, the biomaterial's effect on MSC differentiation was also investigated. MSCs were grown in two groups: (1) on porous PLA/PCL/HAP scaffolds in osteogenic differentiation medium or (2) encapsulated in alginate in chondrogenic differentiation medium. CM was taken from one group and administered to the 'opposite' group in volumetric concentrations of 25% or 50% at each medium change. The osteogenic group samples that were administered chondrocyte CM showed higher alkaline phosphatase activity than the controls that were not administered CM. Additionally, the cells that were given chondrocyte CM had higher osteocalcin and sialoprotein expression than the controls. Samples in the chondrogenic group that were administered osteoblast CM at a volumetric concentration of 50% produced more sGAG than the controls. The aggrecan and Sox9 expression was significantly higher in the samples given 50% CM as compared to the controls. The study also showed that culturing cells in alginate, without differentiation medium, can produce similar levels of differentiation as cells that were administered differentiation medium.     

人骨髓间质干细胞与新型可降解材料生物相容性的实验研究

目的：本研究利用人骨髓间质干细胞（MSC）的增殖与分化潜能作为指标，对可降解偏磷酸钙（dCMP）材料和羟基磷灰石（HA）材料的生物相容性进行体外研究。 方法： 通过扫描电镜观察MSC在dCMP表面粘附的情况，并利用ICP和IC分析dCMP和HA的降解产物元素含量，同时采用FACS、ALP活性检测及ARS等方法对降解产物的毒性效应进行检测。 结果： dCMP对MSC的增殖有促进作用，且不影响MSC的成骨分化进程及分化后的矿化功能；而HA对MSC的成骨分化进程无影响，但对MSC的增殖和成骨分化后的矿化功能均有抑制作用。 结论： dCMP的生物相容性较HA为佳，更适合作为骨替代材料。     

RGD多肽修饰的改性PLGA仿生支架材料对骨髓间充质干细胞粘附、增殖及分化影响的研究

目的：探索RGD多肽修饰的改性PLGA支架材料上骨髓基质细胞的增殖、粘附及分化情况。方法用异型双功能交联剂Sulfo-LC-SPDP将GRGDSPC多肽共价结合到改性PLGA支架材料上，以未接多肽的改性PLGA材料做对照，取第三代MSC接种到材料上，培养1d、2d、3d、4d后比较材料上的细胞密度来反映细胞的增殖程度；取第三代MSC接种到材料上，培养4h、12h后沉淀法定量检测粘附的细胞数，培养24h后摄光镜图像比较粘附细胞的数量和形态，并用FITC连接的鬼笔环肽对细胞骨架染色，在荧光显微镜下观察细胞骨架的组织情况；取第三代MSC接种到材料上，用成骨性培养基培养7d、14d、21d，检测细胞中ALP活性来了解MSC分化情况。结果：培养1d、2d、3d、4d后细胞的增殖程度无显著性差异；培养4h、12h后实验组细胞粘附率均显著高于对照组，且24h后细胞的粘附质量、细胞骨架的组织情况也较对照组为好；培养14d后实验组细胞表达显著高的ALP活性。结论：RGD多肽修饰对细胞增殖无明显促进作用，但能提高改性PLGA支架材料对骨髓基质细胞的粘附性，对MSC向成骨细胞分化有显著促进作用。