培養環境對間葉系幹細胞進行軟骨細胞分化之影響

間葉系幹細胞是可由人類骨髓分離出來的一種幹細胞，此細胞具有極佳的體外增生及分化能力，可以經由培養的方式分化成軟骨細胞、硬骨細胞及脂肪細胞。在間葉系幹細胞的分化過程中，分化環境是調控細胞命運的重要角色。當以pellet culture的方法來引導軟骨分化時，需要生長因子如TGF-β1 ( transforming growth factor β1)的引導，使細胞更有效地分化成軟骨。因此本研究的目的，旨在觀察培養的條件對於間葉系幹細胞在軟骨細胞分化過程中的影響。我們推測不同的環境對間葉系幹細胞進行軟骨細胞分化會有不同的影響。因此，本研究觀察胎牛血清對間葉系幹細胞分化成軟骨細胞的影響。研究進行的方式，是將間葉系幹細胞以200g離心成pellet，分別培養在含有2%胎牛血清和無胎牛血清的分化培養基裡，觀察兩周內細胞的變化。由實驗結果發現，在無胎牛血清存在下的軟骨分化過程中，第二型膠原蛋白的表現量比在相同條件下但含有胎牛血清的分化環境強，而且細胞的增殖能力也下降。我們推想當在有胎牛血清的存在下，細胞進行分裂的數目會比較多，當細胞處於增生環境下時也就無法進行分化而影響到幹細胞分化成為軟骨細胞的速度。相對的，在無胎牛血清的環境下，細胞就可以專一地進行細胞分化，而使其分化成軟骨細胞的速度加快，提高分化的效率。雖然添加胎牛血清可以使培養環境更豐富，但是，當細胞要進行分化時，胎牛血清所提供的生長因子可能反而會使細胞處於增殖而不利於分化的情況。本研究的結論是當利用間葉系幹細胞進行軟骨細胞分化實驗時，在無胎牛血清的分化培養環境裡會比在含胎牛血清之分化培養環境中更為理想。

關鍵字

軟骨細胞；間葉系幹細胞；軟骨分化

並列摘要

Mesenchymal stem cells (MSCs) isolated from the human bone marrow show great proliferation and differentiation abilities. These cells can differentiate into chondrocytes, osteocytes and adipocytes. Culture conditions may be an important factor in regulating cell fate during chondrogenesis. The pellet culture method with the addition of TGF-β1 results in a better differentiation of MSCs when compared to the monolayer culture method. The aim of this research is to study the effects of including fetal bovine serum (FBS) in culture media during chondrogenic induction. Our method was to culture MSC pellets in chondrogenic induction media with or without 2% fetal bovine serum (FBS) and allow them to differentiate for two weeks. The results show that without the addition of FBS, cells expressed more type II collagen than did with 2% FBS, whereas cell proliferation was decreased without the addition of FBS. We presume that when FBS is included in the culture media, more cells undergo proliferation while their chondrogenic differentiation ability decreases. On the other hand, cells can only undergo differentiation when they were cultured without FBS, which enhances the rate of chondrogenesis by increasing the differentiation efficiency. Adding FBS may make the condition more favorable for cell proliferation, with much nutrition for cell overgrowth and influencing cell differentiation. The conclusion of this study is that during MSC chondrogenic differentiation, no FBS in culture media results in better induction than in the present of FBS.

並列關鍵字

mesenchymal stem cell ； chondrocyte ； chondrogenesis

參考文獻

Akiyama, H., Chaboissier, M.C., Martin, J.F., Schedl, A., and de Crombrugghe, B. (2002). The transcription factor Sox9 has essential roles in successive steps of the chondrocyte differentiation pathway and is required for expression of Sox5 and Sox6. Genes Dev 16, 2813-2828.

Akiyama, H., Lyons, J.P., Mori-Akiyama, Y., Yang, X., Zhang, R., Zhang, Z., Deng, J.M., Taketo, M.M., Nakamura, T., Behringer, R.R., et al. (2004). Interactions between Sox9 and beta-catenin control chondrocyte differentiation. Genes Dev 18, 1072-1087.

Baldin, V., Lukas, J., Marcote, M.J., Pagano, M., and Draetta, G. (1993). Cyclin D1 is a nuclear protein required for cell cycle progression in G1. Genes & development 7, 812-821.

Bi, W., Deng, J.M., Zhang, Z., Behringer, R.R., and de Crombrugghe, B. (1999). Sox9 is required for cartilage formation. Nat Genet 22, 85-89.

Carrington, J.L. (2005). Aging bone and cartilage: cross-cutting issues. Biochem Biophys Res Commun 328, 700-708.

國際替代計量

培養環境對間葉系幹細胞進行軟骨細胞分化之影響

全文下載

主題瀏覽