Objective To review the research progress of the current methods of inducing bone marrow mesenchymal stem cells (BMSCs) to chondrogenic differentiation in vitro so as to provide references for researches in cartilage tissue engineering. Methods Various methods of inducing BMSCs differentiation into the chondrogenic l ineage in vitro inrecent years were extensively reviewed and analyzed. Results Adding exogenous growth factors is still the mainly methodof inducing BMSCs differentiation into the chondrogenic l ineage; among the members, transforming growth factor β (TGF-β) family is recognized as the most important chondrogenic induction factor. Other important inducing factors include various chemical factors, physical factors, transgenic methods, and the microenvironmental induction. But the problems of low inducing efficiency and unstable inducing effects still exist. Conclusion The progress of chondrogenic induction of BMSCs promotes its util ization in cartilage tissue engineering. Further researches are needed for establ ishing more efficient, simpler, and safer inducing methods.
To study the feasibil ity of human adipose derived stem cells (ADSCs) in monolayer culture induced into smooth muscle cells in vitro as seeding cells in vascular tissue engineering. Methods The mononuclear cells in human adipose were separated by collagenase treatment and seeded on culture dishes with the density of 5 × 105/cm2. Cellswere cultured in M-199 plus 10% FBS. When reaching confluence, the cells were subcultured by 0.1% trypsin and 0.02%EDTA treatment, PDGF-BB (50 ng/mL) and TGF-β1 (5 ng/mL) were added at the passage 1 to enhance the smooth muscle cells’ phenotype. Cells were cultured under the inducing medium for 14 days. The morphology of induced cells was observed under the microscope. Cellular immunofluorescence and RT-PCR were used to determine the expression of smooth muscle cell markers of the post-induced cells. Flow cytometry (FACs) was used to examine the positive rate of induced team. Results Cocultured in M-199 media including TGF-β1 and PDGF-BB, the prol iferating capabil ity of the induced cells was significantly downregulated compared with the uninduced cells(P lt; 0.01). The induced cells exhibited “Hill and Valley” morphology, while the uninduced cells were similar to ADSCs of P0 which had the fibroblast-l ike morphology. The results of immunofluorescence indicated that the induced cells expressed smooth muscle (SM) cell- specific markers including α-smooth muscle actin (α-SMA), SM-myosin heavy chain (SM-MHC) and Calponin. The results of RT-PCR revealed that the induced cells also expressed α-SMA, SM-MHC, Calponin and SM-22α.The positive rates of α-SMA, SM-MHC and Calponin in FACs were 3.26% ± 1.31%, 3.55% ± 1.6% and 4.02% ± 1.81%, respectively, before the cells were induced. However, 14 days after the cell induction, the positive rates were 48.13% ± 8.31%, 45.33% ± 10.68% and 39.13% ± 9.42%, respectively. The positive rates in induced cells were remarkably higher than those in uninduced cells(P lt; 0.01). Conclusion The human ADSCs can be induced to express vascular smooth muscle markers, and they are a new potential source of vascular tissue engineering.