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Updated: Aug 24, 2026
Chondrogenic Pellet Formation from Cord Blood-derived Induced Pluripotent Stem Cells
Published on: June 19, 2017
Chondrogenic differentiation of bovine bone marrow mesenchymal stem cells in pellet cultural system
Darko Bosnakovski1, Morimichi Mizuno, Gonhyung Kim
1Laboratory of Veterinary Surgery, Department of Clinical Science, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. darko@vetmed.hokudai.ac.jp
Objective:
Pluripotent mesenchymal stem cells (MSC) have been isolated and well characterized from several tissue sources, including bone marrow stroma. MSC from different animals showed slight differences in morphology and in the potential to differentiate. In the present study, we isolated MSC from bovine bone marrow and induced chondrogenesis in order to establish a new experimental model of stem cell research.
Methods:
Bone marrow was harvested from 8 calves. For inducing chondrogenesis, MSC were cultured in pellet culture system in a chemically defined medium supplemented with 0 and 10 ng/mL of transforming growth factor beta1 (TGF-beta1). Chondrogenic differentiation was evaluated by histological, immunohistochemical, and in situ hybridization techniques. The degrees of genes expression were measured by quantitative RT-PCR.
Results:
Metachromatic alcian blue staining and immunoreactivity for type II collagen were detected in both pellet groups (0 and 10 ng/mL TGF-beta1) after 7 days of culturing. In situ hybridization demonstrated strong expression of type II collagen and aggrecan mRNAs in the round cells located at the center region of pellets and at densely organized areas. On the other hand, type I collagen mRNA was strongly expressed in the superficial layer of the pellets. After 20 days of pellet culture, expression of type II collagen mRNA in the cells which were not treated by TGF-beta1 was 1.7-fold higher compared with that treated by TGF-beta1.
Conclusion:
Independent, spontaneous chondrogenesis of bovine MSC in pellet culture occurred without addition of any external bioactive stimulators, namely factors from TGF-beta family, which were previously considered necessary.
Insights
Bovine mesenchymal stem cells (MSC) spontaneously undergo chondrogenesis in pellet culture without growth factors. This establishes a novel model for stem cell research and cartilage development studies.
Area of Science:
- Stem Cell Biology
- Tissue Engineering
- Biomaterials
Background:
- Mesenchymal stem cells (MSC) are multipotent cells found in various tissues, including bone marrow.
- Previous research indicated species-specific differences in MSC morphology and differentiation potential.
- Bovine MSC offer a potential model for studying stem cell behavior and cartilage formation.
Purpose of the Study:
- To isolate and characterize mesenchymal stem cells (MSC) from bovine bone marrow.
- To investigate the chondrogenic differentiation potential of bovine MSC in a pellet culture system.
- To establish a new experimental model for stem cell research, particularly for cartilage development.
Main Methods:
- Bone marrow was harvested from eight calves.
- MSC were cultured in a pellet system with or without transforming growth factor beta1 (TGF-beta1).
- Chondrogenic differentiation was assessed using histological, immunohistochemical, and gene expression analyses (RT-PCR).
Main Results:
- Histological analysis revealed chondrogenesis markers (alcian blue, type II collagen) in both TGF-beta1 treated and untreated groups.
- In situ hybridization confirmed expression of type II collagen and aggrecan mRNA in differentiated cells.
- Interestingly, type II collagen mRNA expression was 1.7-fold higher in untreated MSC after 20 days, suggesting spontaneous chondrogenesis.
Conclusions:
- Bovine MSC undergo spontaneous chondrogenesis in pellet culture without requiring external TGF-beta1 stimulation.
- This finding challenges the necessity of TGF-beta family factors for initiating chondrogenesis in this model.
- The study establishes a novel, simplified experimental model for investigating stem cell-based cartilage research.
