RÉSUMÉ
Objective To investigate the effect of transition between hypoxia and normoxia on proliferation of rabbit mesenchymal stem cells(rMSCs).Methods rMSCs expanded in hypoxia were divided into two groups:L-L group and L-N group.Moreover,rMSCs expanded in normoxia were also divided into two groups:N-N group and N-L group.The L-L and N-L groups were subsequently subcultured in hypoxia,and L-N and N-N groups in normoxia.Growth curve,colony-forming efficiency,glucose and lactate metabolism,and intracellular ROS generation of the four groups were examined.Results In L-L group cell density and colony-forming efficiency were the highest,and intracellular ROS generation was the lowest,whereas reversed results were obtained in N-N group.Cells cultured in hypoxic conditions exhibited higher glucose consumption,lactate production and yield coefficients of lactate from glucose compared to normoxic ones.Conclusion Hypoxia may enhance the proliferation of rMSCs in continuous subcultures.There is a potential link between intracellular ROS generation and expansion of rMSCs.
RÉSUMÉ
PURPOSE: Bone and cartilage were manufactured by using tissue engineering of mesenchymal stem cell (MSC) which can differentiate into variety of cell types. MATERIAL AND METHOD: MSC was isolated and cultured from the rabbit weighing 500g, and it was seeded into PGA mesh and pre-cultured for 1 week with different TGF- beta 3 treated conditions. It was implanted into nude mice and tissues generated were recovered from 1, 2, 3, 4, 8 ,and 12 weeks respectively. Degree of bone and cartilage formation was analyzed with histology and immunohistochemistry assay. RESULT: Pre-culture condition with TGF- beta 3 treatment showed early start of chondrogenic differentiation, and degree of bone and cartilage formation was promoted as time passed. But both of the cases differentiated into complete bone after 12 weeks. CONCLUSION: The results show that pretreatment of TGF- beta 3 promotes the differentiation process in vivo condition under the in vivo system where MSC differentiate into bone via cartilage formation.