Experimental Studies on the Effects of Glycitinregulated TGF-β Signaling Pathway on the Proliferation, Osteogenic, and Lipogenic Differentiation of BMSCs

Abstract

Background Glycitin, generated from the seeds of the legume soybean, has an essential function in antioxidant, obesity inhibition, and wound healing promotion. Furthermore, recent research has shown that it has anti-inflammatory and cartilage-protective properties. Objectives This study was designed to investigate the osteogenic effects of glycitin and the transforming growth factor-β (TGF-β) signaling pathway on bone marrow mesenchymal stem cells (BMSCs), as well as their interaction. Materials and Methods We isolated rabbit BMSCs by whole bone marrow adherent method and cultured, identified, and induced differentiation. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method was used to determine the proliferation ability of BMSCs with different concentrations of glycitin at different times; reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression levels of osteogenesis-related genes runt-related transcription factor 2 (Runx2), collagen type I (Col-1), and osteocalcin (OC) mRNA; and a kit was used to determine the activities of alkaline phosphatase and triglycerides (TG) in BMSCs. A Western blot was used to detect the expression of TGF-β protein in each group. Results On the fifth day of BMSC primary culture, the morphology of long spindle-shaped cells might be plentiful, dominated by a daisy-like or whirling arrangement. They proliferated rapidly and fused to 70%–80% on the eighth day of culture; the third generation of BMSCs was taken for phenotyping, and the detection results of flow cytometry analysis showed that the surface antigenic markers of BMSCs, CD44, and CD90 were positive, whereas CD34 and CD45 were negative; after osteogenic induction of BMSCs, visible calcified nodules were evident. There was cartilage matrix formation after osteogenic induction; glycitin promoted BMSC proliferation in a time-dependent and dose-dependent manner, and BMSC proliferation increased significantly at 20 µM glycitin for 3–5 days; glycitin increased the expression of Runx2, Col-1, and OC mRNA in BMSCs and increased the activity of alkaline phosphatase (ALP) while decreasing the activity of TG. Meanwhile, 20 µM glycitin dramatically increased the expression of TGF-β. Conclusion These findings imply that glycitin increases BMSCs proliferation and osteogenic differentiation. By regulating the TGF-β signaling pathway, glycitin modulates the differentiation of BMSCs into osteoblasts.