[Study on the differentiation of rat bone marrow mesenchymal stem cells into chondrocytes induced by TGF-beta 3].

Objective: To explore the methods for the differentiation of rat bone marrow mesenchymal stem cells (BMMSCs) into chondrocytes induced by transforming growth factor (TGF)-beta 3 in vitro, and search for a reliable seed cell for the regeneration and repair of articular cartilage in osteoarthritis. Methods: SD rat femoral and tibial BMMSCs were cultured by the whole bone marrow adherent method, and then the purity was identified by flow cytometry. P3 generation cells were induced and differentiated into chondrocytes by the induction of differentiation medium containing TGF-beta 3, and cell chondrogenic differentiation ability at different induction time points was detected. Results: The primary and passage cultured BMMSCs were spindle-shaped, and partly triangular. After passage, the proliferation rate of P3 generation cells was fast, like the growth of fish shoal or eddy. After chondrogenic induction, the cells were polygonal and triangular in the form of cluster growth, which was similar to chondrocyte morphology, and the cell proliferation was decreased. Immunofluorescence staining and Western blotting method showed that the cells had a large number of col Ⅱ fluorescent expression, and cells and extracellular matrix was stained blue by Alcian blue staining, with no significant difference at day 7 and day 14. After using Wnt signal blocker, col Ⅱ protein expression was significantly reduced, with statistically significant difference (P<0.05). Conclusion: TGF-beta 3 can rapidly induce the differentiation of BMMSCs into cartilage cells, which provides a good carrier for BMMSCs transplantation and the repair of articular cartilage, and thus to treat osteoarthritis.

Fibroin protein/chitosan scaffolds and bone marrow mesenchymal stem cells culture in vitro.

A previous experiment demonstrated that fibroin protein and chitosan mixed in proper proportion presented good physical and chemical properties and biological characteristics, which can make up for their respective disadvantages. To observe the growth of bone marrow mesenchymal stem cells (BMSCs) on these fibroin protein/chitosan 3D scaffolds, induced rabbit BMSCs were seeded on fibroin protein/chitosan scaffolds. The cell adhesion rate was measured, and cell growth was observed under an inverted microscope and a scanning electron microscope. The cell adhesion rate increased with time. The inverted microscope observations showed that the cells on fibroin protein/chitosan scaffolds could not be seen clearly. As time passed, the number of cells around the stent increased and some cells stretched inside the scaffolds. Electron microscopy showed active cell growth and normal proliferation, and the granular and filamentous matrix substances could be seen around cells. The microfilaments of cell and scaffold materials were tightly connected. The cells not only grew on the surface of the adherent material, but also stretched inside of the materials. These results indicated that the fibroin protein/ chitosan mixed scaffolds have good biocompatibility.