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2022, Vol. 26 ›› Issue (13): 2034-2039Hypoxic precondition rescues osteogenic potential of bone marrow mesenchymal stem cells derived from ovariectomized ratsHuang Xiaoxiong1, 2, Chen Weikai1, 2, Liu Tao1, Yang Huilin1, 2, He Fan1, 2
Abstract: BACKGROUND: Hypoxia is one of the main driving forces regulating the angiogenesis-osteogenesis differentiation process. Hypoxia treatment of cells before differentiation is considered to maintain the stemness and enhance the osteogenic potential of stem cells. However, it is not clear whether hypoxic precondition could improve the osteogenic potential of bone marrow mesenchymal stem cells derived from osteoporosis rat. OBJECTIVE: To investigate the effects of hypoxic precondition on the osteogenic potential of bone marrow mesenchymal stem cells derived from osteoporosis rat and the role of hypoxia inducible factor-1α. METHODS: Ovariectomized SD rat models were established. Bone marrow mesenchymal stem cells were isolated from femurs of female rats in ovariectomized group and sham operation group. The bone marrow mesenchymal stem cells were divided into three groups. In the normal group, the bone marrow mesenchymal stem cells extracted from the sham rats were cultured in the incubator with normal oxygen concentration (21% O2). In the osteoporosis group, the bone marrow mesenchymal stem cells extracted from the ovariectomized rats were cultured in the incubator with normal oxygen concentration (21% O2). In the hypoxia group, the bone marrow mesenchymal stem cells extracted from the ovariectomized rats were cultured in the hypoxic incubator with hypoxic oxygen concentration (5% O2). CCK-8 assay was used to assess the proliferation capacity of bone marrow mesenchymal stem cells by measuring absorbance values at 1, 3, 5, and 7 days. After 72 hours of incubation in hypoxic environment, cells were moved to normal incubator for osteogenic differentiation with other two groups for 14 days. Alizarin red staining and qRT-PCR were utilized to detect osteogenic related gene expression levels. Finally, the bone marrow mesenchymal stem cells of the osteoporosis group were transfected with small interfering RNA to silence the expression of hypoxia inducible factor-1α, cultured in a hypoxic environment for 72 hours, and transferred to a normal incubator for osteogenic differentiation for 14 days. The changes in osteogenic capacity were observed after silencing hypoxia inducible factor-1α. After the silence of HIF-1α, the expressions of HIF-1α and osteogenic markers were furthered detected. RESULTS AND CONCLUSION: (1) The proliferation ability of bone marrow mesenchymal stem cells in ovariectomized rats decreased, and the osteogenic differentiation ability was impaired. (2) Hypoxia successfully accelerated the proliferation of bone marrow mesenchymal stem cells, promoted the deposition of matrix mineralization and the expression of osteogenic related genes. (3) Positive effects of hypoxic precondition on osteogenic potential after the silence of hypoxia inducible factor-1α were eliminated. (4) Results suggested that hypoxic precondition could improve the proliferation and osteogenic potential of bone marrow mesenchymal stem cells of ovariectomized rats and hypoxia inducible factor-1α activated by hypoxia may play an important effect on osteogenic differentiation. Key words:stem cells, bone marrow mesenchymal stem cells, osteoporosis, hypoxia, cell proliferation, osteogenic differentiation, hypoxia inducible factor-1α |