Development of repair method for osteochondral defect using mesenchymal stem cells derived form umbilical cord blood

1.间充质干细胞被认为是多潜能的，能够分化成多个谱系。我们试图表征来自胎儿循环血液（FCBCs）的大鼠细胞，这些细胞显示成纤维细胞形态并分化为成骨细胞和软骨细胞谱系。值得注意的是，它们在仅添加10%胎牛血清的塑料培养皿中分化为软骨细胞特异性表型，而不使用三维培养基质。我们还确定了适当的采收期以获得更多的FCBCs，并测量了FCBCs的倍增时间。在相同的培养条件下，骨髓间充质干细胞不表达COL2A1或COL10A1 mRNA。FCBCs表达两种II型胶原剪接形式IIA和IIB。IIA型基因在FCBCs中的表达高于在原代培养的大鼠肋软骨软骨细胞中的表达，因此，FCBCs被认为比肋软骨软骨细胞更不成熟。持续培养可促进fcbcs分化的软骨细胞成熟。传代培养降低了fcbcs的自发分化能力。我们评估了冷冻FCBCs的自发分化能力。冷冻后的FCBCs仍能分化成成骨细胞和软骨细胞。在不添加10%胎牛血清的情况下，FCBCs分化为成脂细胞。这些结果表明，FCBCs的自发分化能力不受血清因子的影响。我们研制了II型胶原海绵作为骨软骨缺损修复的支架材料。

1.Mesenchymal stem cells are thought to be multipotential, capable of differentiating into multiple lineages. We attempted to characterize rat cells derived from fetal circulating blood (FCBCs) that displayed a fibroblastic morphology and differentiated into osteoblastic and chondrocytic lineages. Notably, they differentiated into a chondrocyte-specific phenotype on plastic culture dishes in medium supplemented only with 10% fetal bovine serum, without the use of a three-dimensional culture substrate. We also determined the adequet harvest period to get more FCBCs and measured the doubling time of FCBCs.2.Mesenchymal stem cells derived from bone marrow did not express COL2A1 or COL10A1 mRNA under the same culture conditions. FCBCs expressed two splice forms of type II collagen, IIA and IIB. Gene expression of type IIA in FCBCs was more than that in primary cultured rat rib cartilage derived chondrocytes, therefore, FCBCs was thought to be more immature than rib cartilage chondrocytes.3.Continuous culture promoted the maturation of chondrocytic cells differentiated from FCBCs.4.Passage culture decreased the ability of spontaneous differentiation of FCBCs.5.We evaluated the ability of spontaneous differentiation with frozen FCBCs. Frozen FCBCs maintained the ability and differentiated into osteoblastic and chondrocytic cells.6.FCBCs differentiated into adipogenic cells without 10% fetal bovine serum. These result showed that spontaneous differentiation ability of FCBCs was independent of the factors in the serum.7.We developed the type II collagen sponge as a scaffold for the repair of osteochondral defect.