Osteoblasts play an important role in bone regeneration and repair. The hypoxia condition in bone occurs when bone undergoes fracture, and this will trigger a series of biochemical and mechanical changes to enable bone repair. Hence, it is interesting to observe the metabolites and metabolism changes when osteoblasts are exposed to hypoxic condition. This study has looked into the response of human osteoblast hFOB 1.19 under normoxic and hypoxic conditions by observing the cell growth and utilization of metabolites via Phenotype MicroArrays™ under these two different oxygen concentrations. The cell growth of hFOB 1.19 under hypoxic condition showed better growth compared to hFOB 1.19 under normal condition. In this study, osteoblast used glycolysis as the main pathway to produce energy as hFOB 1.19 in both hypoxic and normoxic conditions showed cell growth in well containing dextrin, glycogen, maltotriose, D-maltose, D-glucose-6-phospate, D-glucose, D-mannose, D-Turanose, D-fructose-6-phosphate, D-galactose, uridine, adenosine, inosine and α-keto-glutaric acid. In hypoxia, the cells have utilized additional metabolites such as α-D-glucose-1-phosphate and D-fructose, indicating possible activation of glycogen synthesis and glycogenolysis to metabolize α-D-glucose-1-phosphate. Meanwhile, during normoxia, D-L-α-glycerol phosphate was used, and this implies that the osteoblast may use glycerol-3-phosphate shuttle and oxidative phosphorylation to metabolize glycerol-3-phosphate. Impact statement Currently, researchers understand that bone cells experience hypoxia during bone injury or fracture. Such stress condition exerts effect on bone regeneration and repair. However, there is limited knowledge on the metabolites and metabolism changes that occur in osteoblast cells when they undergo inherent regeneration and repair under hypoxia. This manuscript describes the use of Phenotype MicroArrays to observe the response of human osteoblast cells under normoxic and hypoxic conditions in terms of cell growth and utilization of metabolites. The human osteoblast cultured under these two different oxygen concentrations showed different growth curve and utilization of metabolites, suggesting oxygen levels play a role in bone repair and healing. We have deduced the main metabolites for osteoblast cells to produce energy under normoxic and hypoxic conditions. The new findings in this research help researchers to understand how hypoxia can influence utilization of metabolites in osteoblast cells, which serve as important knowledge to improve methods for bone regeneration.
Overexpression of CRABP2 inhibits dexamethasone-induced apoptosis in human osteoblast cells