[Show abstract][Hide abstract] ABSTRACT: Purpose:
To optimize methods for seeding cells on granular-type beta-tricalcium phosphate (β-TCP).
Materials and methods:
Bone marrow stromal cells were obtained from rat long bones and cultured in flasks with Minimum Essential Medium, Alpha Modification (αMEM) supplemented with 10% fetal bovine serum (FBS), dexamethasone, ascorbic acid, β -glycerophosphate, and antibiotics. The influence of differential cell seeding densities and dynamic cell seeding conditions (rotation) was investigated using different sizes of β -TCP granules and a subcutaneous implantation model.
Higher cell seeding densities contributed to efficient in vivo bone formation. The rotational seeding did not affect the efficiency but contributed to the uniformity. Although the granule size did not affect the efficiency under the conditions used in this study, large granules showed more uniform distribution of bone regeneration, while small granules showed nonuniform but dense bone formation. Mixtures of relatively large and small granules may be beneficial for both uniform and efficient bone regeneration.
These findings may contribute to stable bone tissue engineering with bone marrow stromal cells and β -TCP granules as a scaffold.
No preview · Article · Jan 2016 · The International journal of oral & maxillofacial implants
[Show abstract][Hide abstract] ABSTRACT: Objectives
To understand the differences and similarities between immunocompetent and immunodeficient mice as ectopic transplantation animal models for bone tissue engineering.Materials and Methods
Osteogenic cells from mouse leg bones were cultured, seeded on ß-TCP granules and transplanted onto the backs of either immunocompetent or immunodeficient nude mice. At 1, 2, 4 and 8 weeks postoperatively, samples were harvested and evaluated by Hematoxylin-Eosin staining, tartrate-resistant acid phosphatase (TRAP) staining and immunohistochemical staining and quantitative PCR.ResultsIn immunocompetent mice, inflammatory cell infiltration was evident at 1 week post-operatively and relatively higher expression of TNF-α and IL-4 was observed. In immunodeficient mice, new bone area and the number of TRAP-positive cells was larger at 4 weeks than in immunocompetent mice. The volume of new bone area in immunodeficient mice was reduced by 8 weeks.Conclusions
Bone regeneration was feasible in immunocompetent mice. However, some differences were observed between immunocompetent and immunodeficient mice in the bone regeneration process possibly due to different cytokine expression, which should be considered when utilizing in vivo animal models.This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Although bone marrow (BM) stromal cells (SC; BMSC) isolated from adherent cultures of untreated BM are known to contain both committed and uncommitted osteogenic cells, it remains unknown whether BMSC isolated either by hemolysis or Ficoll centrifugation also contain both of these populations.
Differences in the osteogenic cell populations of rat BMSC isolated from untreated, hemolyzed or Ficoll-treated BM were analyzed by in vivo transplantation, flow cytometry, alkaline phosphatase (ALP) assay, real-time polymerase chain reaction (PCR) and alizarin red staining.
Transplantation of non-cultured samples indicated that the Ficolled BMSC contained the lowest number of committed osteogenic cells. Flow cytometric analysis of cultured, non-induced samples showed that the percentage of ALP-positive cells was significantly lower in Ficolled BMSC. Quantitative ALP assays confirmed that the lowest ALP activity was in the Ficolled BMSC. Hemolyzed BMSC also contained lower numbers of committed osteogenic cells than untreated BMSC, but still more than Ficolled BMSC. Interestingly, the Ficolled BMSC showed the greatest levels of osteogenic ability when cultured in osteogenic induction medium.
These findings suggest that, although Ficolled BMSC rarely contain committed osteogenic cells, they are able to show comparable or even greater levels of osteogenic ability after induction, possibly because they contain a greater proportion of uncommitted stem cells. In contrast, induction is optional but recommended for both untreated and hemolyzed BMSC before use, because both these groups contain both committed and uncommitted osteogenic cells. These findings are of significant importance when isolating BMSC for use in bone tissue engineering.