Gene expression during induced differentiation of sheep bone marrow mesenchymal stem cells into osteoblasts

The aim of this study was to observe the dynamic expression of osteopontin, type I collagen, and osteocalcin genes during the differentiation of bone marrow mesenchymal stem cells (BMSCs) into osteoblasts and confirm whether BMSCs can differentiate and mature into osteoblasts. A healthy, 2-month-old Altay tailed sheep was obtained, and 10 mL bone marrow was extracted from the posterior superior iliac spine of the sheep via puncture. Sheep BMSCs were extracted using a whole bone marrow culture method and cultured for osteogenic induction. Total RNA from the BMSCs was extracted, and the gene expression levels of osteopontin, type I collagen, and osteocalcin at the 1st, 2nd, 3rd, and 4th passages of uninduced and induced BMSCs were detected using reverse transcription-polymerase chain reaction. The surface antigen CD44 was also detected in the BMSCs. After induction by culturing in osteoinductive medium, BMSCs in the 1st, 2nd, 3rd, and 4th passages displayed stage-specific expression of osteopontin, type I collagen, and osteocalcin genes. The positive expression rate of BMSC-specific antigen CD44 in the 4th passage of osteogenic-induced BMSCs was 99.8%. In vitro-cultured sheep BMSCs in osteogenic culture medium gradually differentiated into osteoblasts, which stage-specifically expressed osteoblast-specific genes such as osteopontin, type I collagen, and osteocalcin at the 4th passage after induction. At this passage, these cells had osteoblast functions.