ObjectiveTo investigate the effect of overexpressing the Indianhedgehog (IHH) gene on the chondrogenic differentiation of rabbit bone marrow mesenchymal stem cells (BMSCs) in a simulated microgravity environment.
MethodsThe 2nd generation BMSCs from rabbit were divided into 2 groups: the rotary cell culture system (RCCS) group and conventional group. Each group was further divided into the IHH gene transfection group (RCCS 1 group and conventional 1 group), green fluorescent protein transfection group (RCCS 2 group and conventional 2 group), and blank control group (RCCS 3 group and conventional 3 group). RCCS group cells were induced to differentiate into chondrocytes under simulated microgravity environment; the conventional group cells were given routine culture and chondrogenic induction in 6 well plates. During differentiation induction, the ELISA method was used to detect IHH protein expression and alkaline phosphatase (ALP) activity, and quantitative real-time PCR to detect cartilage and cartilage hypertrophy related gene expressions, and Western blot to detect collagen typeⅡ, agreecan (ANCN) protein expression; and methylene blue staining and Annexin V-cy3 immunofluorescence staining were used to observe cell slide.
ResultsAfter transfection, obvious green fluorescence was observed in BMSCs under fluorescence microscopy in RCCS groups 1 and 2, the transfection efficiency was about 95%. The IHH protein levels of RCCS 1 group and conventional 1 group were significantly higher than those of RCCS 2, 3 groups and conventional 2, 3 groups (P < 0.05); at each time point, ALP activity of conventional 1 group was significantly higher than that of conventional 2, 3 groups (P < 0.05); ALP activity of RCCS 1 group was significantly higher than that of RCCS 2 and 3 groups only at 3 and 7 days (P < 0.05). Conventional 1 group expressed high levels of cartilage-related genes, such as collagen typeⅡand ANCN at the early stage of differentiation induction, and expressed high levels of cartilage hypertrophy-related genes, such as collagen type X, ALP, and Annexin V at the late stage (P < 0.05). RCCS 1 group expressed high levels of cartilage-related genes and low levels of cartilage hypertrophy-related genes at all stages. The expression of collagen typeⅡprotein in conventional 1 group was significantly lower than that of conventional 2 and 3 groups at 21 days after induction (P < 0.05); RCCS 1 group expressed high levels of collagen typeⅡand ANCN proteins at all stages (P < 0.05). Methylene blue staining indicated conventional 1 group was stained lighter than conventional 2 and 3 groups at 21 days after induction; while at each time point RCCS 1 group was significantly deeper than RCCS 2 and 3 groups. Annexin V-cy3 immunofluorescence staining indicated the red fluorescence of conventional 1 group was stronger than that of conventional 2 and 3 groups at each time point. The expression of red fluorescence in each RCCS subgroup was weak and there was no significant difference between the subgroups.
ConclusionUnder the simulated microgravity environment, transfection of IHH gene into BMSCs can effectively promote the generation of cartilage and inhibit cartilage aging and osteogenesis. Therefore, this technique is suitable for cartilage tissue engineering.
ObjectiveTo study the hydrophilicity and the cell biocompatibility of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) coated with a fusion protein polyhydroxyalkanoates granule binding protein (PhaP) fused with Arg-Gly-Asp (RGD) peptide (PhaP-RGD).
MethodsPHBV and PHBHHx films were fabricated by solvent evaporation.Scanning electronic microscope (SEM) was used to study the morphology of the films.PhaP-RGD fusion proteins were expressed and purified by the technology of protein engineering; PHBV and PHBHHx films were immersed in the PhaP-RGD with an amount of 3.5 mg/mL protein/per sample respectively.The hydrophilicity of the surface were detected by the contact angle measurements.Septal cartilage cells obtained from human septal cartilage were cultured in vitro.The 2nd passage chondrocytes were incubated on PHBV unmodified with PhaP-RGD in group A1,PHBV modified with PhaP-RGD in group A2,PHBHHx unmodified with PhaP-RGD in group B1,PHBHHx modified with PhaP-RGD in group B2,and on the cell culture plates in group C.After cultured for 3 days,the proliferation of cells was detected by the DAPI staining; the proliferation viability of cells was detected by the MTT assay after cultured for 3 and 7 days; after cultured for 7 days,the adhesion and morphology of the cells on the surface of the biomaterial films were observed by SEM and the matrix of the cells was detected through the toluidine blue staining.
ResultsSEM observation showed that PHBV and PHBHHx films had porous structures.The contact angle of the surface of the PHBV and PHBHHx films modified with PhaP-RGD fusion proteins were significantly reduced when compared with the films unmodified with PhaP-RGD fusion proteins (P<0.05).Chondrocytes of human nasal septal cartilage incubated on the films could grow in all groups.After 3 days of cultivation in vitro,the cell proliferation and viability of group B2 were the strongest among all groups (P<0.05); the cell proliferation after cultured for 7 days was significantly stronger than that after cultured for 3 days in groups A1,A2,B1,and B2 (P<0.05); and the cell proliferation was significantly stronger in groups B1 and B2 than groups A1,A2 and C,in group B2 than group B1,and in group A1 than group A2 (P<0.05).The results of toluidine blue staining showed that blue metachromasia matrixes were observed in groups A1,A2,B1,and B2; group A1 and group A2 had similar staining degree,and the staining of group B2 was deeper than that of group B1.The adhesion of cells in all groups was good through SEM observation; and the connection of cells formed and stretched into the pores of the materials.
ConclusionThe biomaterial films of PHBHHx modified with PhaP-RGD fusion protein can promote its biocompatibility with chondrocytes.
ObjectiveTo study the preparation method of acellular dermal matrix (ADM) for cartilage tissue engineering and analyze its biocompatibility.
MethodsThe dermal tissues of the calf back were harvested, and decelluarized with 0.5% SDS, and the ADM was reconstructed with 0.5% trypsin, cross-linked with formaldehyde, and modified with 0.5% chondroitin sulfate which can promote the proliferation of chondrocytes. And the porosity, cytotoxicity, and biocompatibility were determined. Co-cultured 2nd passage chondrocytes and bone marrow stromal cells in a proportion of 3 to 7 were used as seed cells. The cells were seeded on ADM (experimental group) for 48 hours to observe the cell adhesion. The expressions of mRNA and protein of collagen type Ⅱ were tested by RT-PCR and Western blot methods, respectively. And the expressions were compared between the cells seeded on the scaffold and cultured in monolayer (control group).
ResultsAfter modification of 0.5% trypsin, the surface of ADM was smooth and had uniform pores; the porosity (85.4%±2.8%) was significantly higher than that without modification (72.8%±5.8%) (t=-4.384, P=0.005). The cell toxicity was grade 1, which accords to the requirements for cartilage tissue engineering scaffolds. With time passing, the number of inflammatory cells decreased after implanted in the back of the rats (P<0.05). The scanning electron microscope observation showed that lots of seed cells adhered to the scaffold, the cells were well stacked, displaying surface microvilli and secretion. The expressions of mRNA and protein of collagen type Ⅱ were not significantly different between experimental and control groups (t=1.265, P=0.235;t=0.935, P=0.372).
ConclusionThe ADM prepared by acellular treatment, reconstruction, cross-linking, and modification shows perfect characters. And the seed cells maintain chondrogenic phenotype on the scaffold. So it is a proper choice for cartilage tissue engineering.
Objective
To evaluate the synergistic effect of bone morphogenetic protein 14 (BMP-14) and chondrocytes co-culture on chondrogenesis of adipose-derived stem cells (ADSCs) so as to optimize the source of seed cells for cartilage tissue engineering.
Methods
ADSCs and chondrocytes were isolated and cultured respectively from articular cartilage and subcutaneous fat of 2 male New Zealand white rabbits (weighing, 1.5 kg and 2.0 kg). The cells at passage 3 were harvested for experiment. ADSCs were identified by osteogenic induction (alizarin red staining), chondrogenic induction (alcian blue staining), and adipogenic induction (oil red O staining). The optimum multiplicity of infection (MOI) of transfection of adenovirus-cytomegalovirus (CMV)-BMP-14-internal ribosome entry site (IRES)-human renilla reniformis green fluorescent protein 1 (hrGFP-1) was determined and then ADSCs were transfected by the optimum MOI. The experiment was divided into 5 groups: group A, co-culture of ADSCs transfected by BMP-14 and chondrocytes (1
∶
1 in Transwell chambers); group B, co-culture of ADSCs and chondrocytes (1
∶
1 in Transwell chambers); group C, culture of ADSCs transfected by BMP-14; group D, simple chondrocytes culture; and group E, simple ADSCs culture. After 3 weeks, the glycosaminoglycan (GAG) content was detected by alcian blue staining; the expressions of collagen type II and BMP-14 protein were detected by Western blot; expression of Sox-9 gene was detected by RT-PCR.
Results
The cultured cells were proved to be ADSCs by identification. Inverted fluorescence microscope showed optimum transfection effect when MOI was 150. GAG content, expressions of collagen type II and BMP-14 protein, expression of Sox-9 gene were significantly higher in groups A and C than in the other 3 groups, in group A than in group C (P lt; 0.05), and groups B and D were significantly higher than group E (P lt; 0.05), but no significant difference was found between groups B and D (P gt; 0.05).
Conclusion
It can promote differentiation of ADSCs into chondrocytes by BMP-14 co-culture with chondrocytes, and they have a synergistic effect.
【Abstract】 Objective To investigate the secretion of target gene and differentiation of BMSCs transfected by TGF-β1 and IGF-1 gene alone and together into chondrocytes and to provide a new method for culturing seed cells in cartilage tissue engineering. Methods The plasmids pcDNA3.1-IGF-1 and pcDNA3.1-TGF-β1 were ampl ified and extracted, then cut by enzymes, electrophoresed and analyzed its sequence. BMSCs of Wistar rats were separated and purificated by the density gradient centrifugation and adherent separation. The morphologic changes of primary and passaged cells were observed by inverted phase contrast microscope and cell surface markers were detected by immunofluorescence method. According to the transfect situation, the BMSCs were divided into 5 groups, the non-transfected group (Group A), the group transfected by empty vector (Group B), the group transfected by TGF-β1 (Group C), the group transfected by IGF-1 (Group D) and the group transfected both by TGF-β1 and IGF-1 (Group E). After being transfected, the cells were selected, then the prol iferation activity was tested by MTT and expression levels were tested by RT-PCR and Western blot. Results The result of electrophoresis showedthat sequence of two bands of the target genes, IGF-1 and TGF-β1, was identical with the sequence of GeneBank cDNA. A few adherent cells appeared after 24 hours culture, typical cluster formed on the forth or fifth days, and 80%-90% of the cells fused with each other on the ninth or tenth days. The morphology of the cells became similar after passaging. The immunofluorescence method showed that BMSCs were positive for CD29 and CD44, but negative for CD34 and CD45. A few cells died after 24 hoursof transfection, cell clone formed at 3 weeks after selection, and the cells could be passaged at the forth week, most cells became polygonal. The boundary of some cells was obscure. The cells were round and their nucleus were asymmetry with the particles which were around the nucleus obviously. The absorbency values of the cells tested by MTT at the wavelength of 490 nm were0.432 ± 0.038 in group A, 0.428 ± 0.041 in group B, 0.664 ± 0.086 in group C, 0.655 ± 0.045 in group D and 0.833 ± 0.103 in group E. The differences between groups A, B and groups C, D, E were significant (P lt; 0.01). The differences between groups A and B or between C, D and E were not significant (P gt; 0.05)。RT-PCR and Western blot was served to detect the expression of the target gene and protein. TGF-β1 was the highest in group C, 0.925 0 ± 0.022 0, 124.341 7 ± 2.982 0, followed by group E, 0.771 7 ± 0.012 0, 101.766 7 ± 1.241 0（P lt; 0.01）; The expression of IGF-1 was the highest in group E, 1.020 0 ± 0.026 0, 128.171 7 ± 9.152 0, followed by group D, 0.465 0 ± 0.042 0, 111.045 0 ± 6.248 0 （P lt; 0.01）. And the expression of collagen II was the hignest in group E, 0.980 0 ± 0.034 0, 120.355 0 ± 12.550 0, followed by group C, 0.720 0 ± 0.026 0, 72.246 7 ± 7.364 0（P lt; 0.01）. Conclusion The repairment of cartilage defects by BMSCs transfected with TGF-β1 and IGF-1 gene together hasa good prospect and important significance of cl inic appl ication in cartilage tissue engineering.
ObjectiveTo review the research progress of different cell seeding densities and cell ratios in cartilage tissue engineering. MethodsThe literature about tissue engineered cartilage constructed with three-dimensional scaffold was extensively reviewed, and the seeding densities and ratios of most commonly used seed cells were summarized. ResultsArticular chondrocytes (ACHs) and bone marrow mesenchymal stem cells (BMSCs) are the most commonly used seed cells, and they can induce hyaline cartilage formation in vitro and in vivo. Cell seeding density and cell ratio both play important roles in cartilage formation. Tissue engineered cartilage with good quality can be produced when the cell seeding density of ACHs or BMSCs reaches or exceeds that in normal articular cartilage. Under the same culture conditions, the ability of pure BMSCs to build hyaline cartilage is weeker than that of pure ACHs or co-culture of both. ConclusionDue to the effect of scaffold materials, growth factors, and cell passages, optimal cell seeding density and cell ratio need further study.
Objective
To investigate the feasibility of fabricating an oriented scaffold combined with chondrogenic-induced bone marrow mesenchymal stem cells (BMSCs) for enhancement of the biomechanical property of tissue engineered cartilage in vivo.
Methods
Temperature gradient-guided thermal-induced phase separation was used to fabricate an oriented cartilage extracellular matrix-derived scaffold composed of microtubules arranged in parallel in vertical section. No-oriented scaffold was fabricated by simple freeze-drying. Mechanical property of oriented and non-oriented scaffold was determined by measurement of compressive modulus. Oriented and non-oriented scaffolds were seeded with chondrogenic-induced BMSCs, which were obtained from the New Zealand white rabbits. Proliferation, morphological characteristics, and the distribution of the cells on the scaffolds were analyzed by MTT assay and scanning electron microscope. Then cell-scaffold composites were implanted subcutaneously in the dorsa of nude mice. At 2 and 4 weeks after implantation, the samples were harvested for evaluating biochemical, histological, and biomechanical properties.
Results
The compressive modulus of oriented scaffold was significantly higher than that of non-oriented scaffold (t=201.099, P=0.000). The cell proliferation on the oriented scaffold was significantly higher than that on the non-oriented scaffold from 3 to 9 days (P lt; 0.05). At 4 weeks, collagen type II immunohistochemical staining, safranin O staining, and toluidine blue staining showed positive results in all samples, but negative for collagen type I. There were numerous parallel giant bundles of densely packed collagen fibers with chondrocyte-like cells on the oriented-structure constructs. Total DNA, glycosaminoglycan (GAG), and collagen contents increased with time, and no significant difference was found between 2 groups (P gt; 0.05). The compressive modulus of the oriented tissue engineered cartilage was significantly higher than that of the non-oriented tissue engineered cartilage at 2 and 4 weeks after implantation (P lt; 0.05). Total DNA, GAG, collagen contents, and compressive modulus in the 2 tissue engineered cartilages were significantly lower than those in normal cartilage (P lt; 0.05).
Conclusion
Oriented extracellular matrix-derived scaffold can enhance the biomechanical property of tissue engineered cartilage and thus it represents a promising approach to cartilage tissue engineering.
ObjectiveTo isolate and culture cartilage derived stem cells from different subtypes of cartilages, and to identify their characteristics.
MethodsCartilage derived stem cells were isolated from different subtypes of cartilages (auricle cartilage, articular cartilage, and intervertebral cartilage) by using adhesive method of fibronectin. The expressions of positive surface markers (CD29 and CD90) and negative surface markers (CD34 and CD45) in cartilage derived stem cells were detected via flow cytometry. The single cell colony-forming efficiency of cartilage derived stem cells was determined by clonal formation unit test; the multipotent differentiation capacity was identified by chondrogensis, osteogenesis, and adipogenesis induction. RT-PCR was used to test the expression of osteogenic, chondrogenic, and adipogenic genes; and bone marrow mesenchymal stem cells (BMSCs) served as control.
ResultsThree cell populations were successfully isolated from different subtypes of cartilages, which could express CD29 and CD 90 highly, but did not express CD34 and CD45. After 2 weeks of culture, single cartilage derived stem cell could form single cell colony. In addition, cartilage derived stem cells had high chondrogenesis, osteogenesis, and adipogenesis potentials. After osteogenic induction, the expressions of collagen type Ⅰ and collagen type X in articular and intervertebral cartilage stem cells were significantly higher than those in BMSCs (P<0.05), while there was no significant difference between auricular cartilage stem cells and BMSCs (P>0.05). The expressions of Aggrecan and collagen type Ⅱ in cartilage derived stem cells after chondrogenic induction were significantly higher than those in BMSCs (P<0.05). While the ability of adipogenic differentiation was lower than that in BMSCs, but no significant difference was found (P>0.05).
ConclusionCartilage derived stem cells in different subtypes of cartilages possess typical characteristics of stem cells.
ObjectiveTo observe transforming growth factor β3 (TGF-β3) gene expression and the chondrogenesis of bone marrow mesenchymal stem cells (BMSCs) after TGF-β3 gene is transfected into BMSCs of Diannan small-ear pig.
MethodsRecombinant adenovirus 5 (rAd5) was extracted as gene vector and packed into recombinant adenovirus rAd5-TGF-β3, double enzyme digestion and PCR identification were performed. BMSCs were isolated and cultured from bone marrow of 2-month-old Diannan small-ear pigs (weighing, 12-15 kg), and the 2nd generation of BMSCs were harvested for experiments. The experiments were divided into 3 groups. BMSCs were transfected with rAd5-TGF-β3 as experimental group and with empty vector as control group, and non-transfected BMSCs were used as blank control group. The transfection efficiency of exogenous gene was identified by flow cytometry, TGF-β3 protein expression by immunofluorescence and Western blot. The cell morphology of experimental group was observed by inverted phase contrast microscope, and the expression of collagen type II in each group was detected by Western blot.
ResultsThe rAd5-TGF-β3 recombinant adenovirus was successfully constructed and transfected into BMSCs. Green fluorescence was observed by immunofluorescence microscope. Flow cytometry test showed the best transfection at 72 hours (transfection efficiency of 84.86%). Immunofluorescence staining showed that the expression of TGF-β3 protein was obvious at 72 hours; Western blot showed that there was a TGF-β3 positive band with a relative molecular mass of 30×103, while the control group and blank control group had no positive band. Obvious chondrogenic differentiation was observed in the experimental group after transfection in vitro, while the control group and blank control group had no obvious chondrogenic differentiation. Western blot showed that there was collagen type II positive band with a relative molecular mass of 130×103 at 21 days after culture, while the control group and blank control group had no positive band.
ConclusionrAd5-TGF-β3 gene can be successfully transfected into BMSCs via adenovirus vectors, and stable expression of TGF-β3 protein can be observed, enhancing BMSCs differentiation into chondrocytes, which may provide an experimental basis for gene therapy of joint cartilage defects.
Objective To review the research progress of the current methods of inducing bone marrow mesenchymal stem cells (BMSCs) to chondrogenic differentiation in vitro so as to provide references for researches in cartilage tissue engineering. Methods Various methods of inducing BMSCs differentiation into the chondrogenic l ineage in vitro inrecent years were extensively reviewed and analyzed. Results Adding exogenous growth factors is still the mainly methodof inducing BMSCs differentiation into the chondrogenic l ineage; among the members, transforming growth factor β (TGF-β) family is recognized as the most important chondrogenic induction factor. Other important inducing factors include various chemical factors, physical factors, transgenic methods, and the microenvironmental induction. But the problems of low inducing efficiency and unstable inducing effects still exist. Conclusion The progress of chondrogenic induction of BMSCs promotes its util ization in cartilage tissue engineering. Further researches are needed for establ ishing more efficient, simpler, and safer inducing methods.
