Preliminary Study on the Differentiation of Bone Marrow Mesenchymal Stem Cells into Chondrocytes Induced by TGF-β1, Yougui Yin Drug-Containing Serum and Mechanical Stimulation

Objective: Bone marrow mesenchymal stem cells (BMSCs) have the potential to differentiate into chondrocytes, it is the ideal seed cells for treating cartilage injury. The purpose of this study was to investigate the inducible factors that stimulate the differentiation of bone marrow mesenchymal stem cells into chondrocytes. Methods: Rat BMSCs were isolated and subcultured, and then inoculated on PLGA scaffolds after successfully identificating of BMSCs. They were divided into 5 groups. Blank serum group, TGF-β1 + Yougui Yin drug-containing serum induction group, TGF-β1 + mechanical stimulation induction group, Yougui Yin drug-containing serum + mechanical stimulation induction group, TGF-β1 + Yougui Yin drug-containing serum + mechanical stimulation induction group, 4 weeks later, the adhesion status of cells and scaffolds was observed by Scanning Electron Microscopy, and then chondrocyte induction was performed on different treatment groups. After induction, the expression of Aggrecan and Collagen II was detected by immunofluorescence, and the mRNA expression of Aggrecan and Collagen II was detected by qPCR. Results: BMSCs were identified as rat bone marrow mesenchymal stem cells by immunofluorescence CD34 and CD44 cells. Scanning Electron Microscopy observed that BMSCs grew well on PLGA. Compared with PLGA group, the scaffold space of BMSCS-PLGA composite was significantly reduced, and the growth of cell adhesion scaffold was significantly increased. Compared with the blank serum group, the expression of Aggrecan in TGF-β1 + Yougui Yin drug-containing serum group and Yougui Yin drug-containing serum + mechanical stimulation group was significantly increased. The expression of Collagen II in TGF-β1 + Yougui Yin medicated serum group, Yougui Yin medicated serum + mechanical stimulation group, TGF-β1 + mechanical stimulation group and TGF-β1 + Yougui Yin medicated serum + mechanical stimulation group were significantly increased; PCR results showed that compared with blank serum group, the expression of Aggrecan in other groups was significantly increased, except for Collagen II expression in Yougui Yin drug-containing serum + mechanical stimulation group. Conclusion: BMSCs can differentiate into chondrocytes on PLGA scaffold. Compared with blank serum group, BMSCs can be induced to differentiate into chondrocytes in all induction groups, among all induction groups, TGF-β1 + Yougui-yin drug-containing serum group and