2025, Vol. 29 ›› Issue (36): 7719-7727

Comparison of osteogenic potential in STRO-1 positive and negative bone marrow mesenchymal stem cells

Zhou Wanlin1, He Bin2, Shen Xiongcheng1, Huang Kun1, Tian Renyuan1, Yuan Ye1, Huang Wenliang3   

Abstract: BACKGROUND: With aging, the regenerative capacity and differentiation function of bone marrow mesenchymal stem cells progressively decline, reducing bone tissue repair efficacy. Thus, identifying bone marrow mesenchymal stem cell subpopulations with enhanced osteogenic potential is of significant importance for advancing bone tissue engineering.
OBJECTIVE: To evaluate the osteogenic differentiation potential differences between STRO-1 positive and negative bone marrow mesenchymal stem cells under osteogenic induction conditions.
METHODS: SD rat bone marrow mesenchymal stem cells were isolated and cultured. The expression of CD29, CD45, CD90, and STRO-1 was identified via flow cytometry and immunofluorescence. Immunomagnetic cell sorting was used to separate STRO-1 positive and negative bone marrow mesenchymal stem cells. The cells of two groups were subjected to osteogenic induction for 7 and 14 days. qRT-PCR and western blotting were performed to analyze differences in osteogenesis-related gene expression (Collagen I, Runt-related transcription factor 2, osteoprotegerin, and osteocalcin) and protein levels. Alizarin red staining and alkaline phosphatase staining were used to observe calcium nodule formation.
RESULTS AND CONCLUSION: Flow cytometry showed high expression levels of CD29 and CD90 and low expression of CD45, with a positive STRO-1 expression rate of 12.8%. Immunofluorescence results were consistent with those of flow cytometry. After magnetic cell sorting, STRO-1 positive cells demonstrated a higher colony formation rate than STRO-1 negative cells. On day 14, STRO-1 positive cells showed significantly higher osteogenic differentiation potential than on day 7, with significantly elevated osteogenesis-related marker levels compared to STRO-1 negative cells (P < 0.01). The findings indicate that STRO-1 positive bone marrow mesenchymal stem cells exhibit significant advantages in osteogenic potential, providing a theoretical basis for their selection as ideal seed cells in bone tissue engineering. In future applications, they may represent a promising therapeutic approach for bone defect repair.

Key words: STRO1, bone marrow mesenchymal stem cells, osteogenic differentiation, immunomagnetic cell sorting, bone defect repair, seed cells, bone tissue engineering, engineered stem cells‍