Chondrogenesis of Human Adipose-Derived Stem Cells by In Vivo Co-graft with Auricular Chondrocytes from Microtia

To evaluate the efficiency of chondrogenesis of human adipose-derived stem cells (ADSCs) induced by auricular chondrocytes from microtia via subcutaneous co-graft in nude mice. Human ADSCs and auricular chondrocytes were mixed at the ratio of 7:3 and suspended in 0.2 ml of Pluronic F-127 (5.0 x 10(7) cells/ml), and injected into Balb/c nude mice as the experimental group (Exp group). The same quantity of auricular chondrocytes (Ctr.1 group) or ADSCs (Ctr.2 group) in 0.2 ml of Pluronic F-127 was set as positive and negative control groups. The mixture of auricular chondrocytes (1.5 x 10(7) cells/ml) in 0.2 ml of Pluronic F-127 was set as the low concentration of chondrocyte control group (Ctr.3). At 8 weeks after grafting, the newly generated tissue pellets were isolated for morphological examination, haematoxylin and eosin staining, toluidine blue staining and safranin O staining of glycosaminoglycan (GAG), Masson's trichrome staining and immunohistochemical staining of type II collagen, and Verhoeff-iron-hematoxylin staining of elastic fibers. GAG content was determined by Alcian blue colorimetric method, and mRNA expression of type II collagen and aggrecan were examined by real-time PCR. Cartilage-like tissue with a white translucent appearance and good elasticity was generated in the Exp and Ctr.1 groups. The tissue pellets in the Ctr.2 and Ctr.3 groups were much smaller than those in the Ctr.1 group. The mature cartilage lacunas could be observed in the Exp and Ctr.1 groups, while were rarely seen in the Ctr.3 group and not observed in the Ctr.2 group. The expression of cartilage-specific extracellular matrix such as type II collagen, GAG content, aggrecan, and elastic fibers in the Exp group was similar to that in the Ctr.1 group, whereas the expression of these extracellular matrix substances was significantly lower in the Ctr.2 and Ctr.3 groups (both P < 0.01). Auricular chondrocytes from microtia can efficiently promote the chondrogenic differentiation and chondrogenesis of ADSCs by co-grafting in vivo. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266.