In vivo matrix-guided human mesenchymal stem cells

Microfracture of subchondral bone results in intrinsic repair of cartilage defects. Stem or progenitor cells from bone marrow have been proposed to be involved in this regenerative process. Here, we demonstrate for the first time that mesenchymal stem (MS) cells can in fact be recovered from matrix material saturated with cells from bone marrow after microfracture. This also introduces a new technique for MS cell isolation during arthroscopic treatment. MS cells were phenotyped using specific cell surface antibodies. Differentiation of the MS cells into the adipogenic, chondrogenic and osteogenic lineage could be demonstrated by cultivation of MS cells as a monolayer, as micromass bodies or mesenchymal microspheres. This study demonstrates that MS cells can be attracted to a cartilage defect by guidance of a collagenous matrix after perforating subchondral bone. Protocols for application of MS cells in restoration of cartilage tissue include an initial invasive biopsy to obtain the MS cells and time-wasting in vitro proliferation and possibly differentiation of the cells before implantation. The new technique already includes attraction of MS cells to sites of cartilage defects and therefore may overcome the necessity of in vitro proliferation and differentiation of MS cells prior to transplantation. Received 3 November 2005; received after revision 15 December 2005; accepted 4 January 2006     

川芎嗪对IL-1β诱导的兔原代软骨细胞增殖和凋亡影响

目的 观察川芎嗪对白细胞介素-1β诱导的软骨细胞的增殖及凋亡的影响.方法 兔原代软骨细胞培养及鉴定,用IL-1β10ng/ml和/或不同浓度川芎嗪共培养兔原代软骨细胞48h后,利用流式细胞仪检测各组软骨细胞的周期及凋亡率;利用MTT法检测软骨细胞的生长状态.结果 与对照组比较,IL-1β诱导下软骨细胞的凋亡率显著增加,差异具有显著统计学意义(P＜0.01);加入川芎嗪能明显降低IL-1β诱导的软骨细胞凋亡率,有显著统计学意义(P＜0.01);与对照组比较,IL-1β诱导下软骨细胞被明显阻滞在G1期(P＜0.01);加入川芎嗪能明显降低IL-1β对软骨细胞G1期的阻滞作用,细胞增殖指数明显增加(P＜0.05或P＜0.01).结论 川芎嗪对IL-1β诱导的兔原代软骨细胞抑制凋亡并促进生长.     

Differentiation of L6 myoblastic cells into chondrocytes

Summary Under the influence of demineralized bone pieces L6 cells differentiate into chondrocytes. The cartilage formed is identifiable histologically. The results demonstrate that these myoblastic cells, which are committed to produce muscle, may still be influenced to express another potentiality of their genome.     

Sox9基因转染诱导L6大鼠成肌细胞向软骨细胞表型分化的研究

利用脂质体转染法,将真核表达质粒pcDNA3.1-Sox9导入L6胞中.通过细胞增殖检测、细胞形态学观察、标志基因表达分析和甲苯胺蓝染色等方法分析Sox9基因转染对L6细胞增殖和向成软骨方向分化的诱导作用.结果表明,Sox9基因转染对L6细胞的增殖能力没有影响,但能明显抑制L6细胞相互融合形成肌管.和对照相比,Sox9基因转染后,细胞成肌分化标志基因Myf5的表达受到明显抑制,而成软骨分化标志基因Ⅱ型胶原（type Ⅱ collagen ,Col2a1）和蛋白聚糖（Aggrecan,Agg）的表达显著     

Hexosaminidase and alkaline phosphatase activities in articular chondrocytes and relationship to cell culture conditions

Hexosaminidase and alkaline phosphatase activities in rabbit articular chondrocytes have been studied under different cell culture conditions. Chondrocytes were cultured in monolayer primary culture, monolayer subcultured to the fifth passage (in vitro aging) and cultured within a collagen gel; enzymatically released cartilage cells were used as control. Under these conditions, the two enzymes behave quite differently in relationship to alteration of the chondrocyte phenotype in culture. Increased lysosomal hexosaminidase activity could be considered to be a marker of the dedifferentiated phenotype in monolayer subculture; membrane alkaline phosphatase activity could be used as a marker of non-proliferating cells.