RBM5-AS1 participates in fracture healing and inhibits apoptosis of bone cells through the up-regulation of β-catenin

Y.-Z. Huang, L. Zhao, C.-L. Wang, S.-J. Tian, S. Liu, J.-F. Ge

Department of Orthopedics, Zhangjiagang Hospital Affiliated to Soochow University, Zhangjiagang, China. gejianfei0271@163.com

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• Orthopedics

OBJECTIVE: The aim of this study was to detect the expression of RBM5-AS1 during fracture healing, and to explore its possible mechanism.

MATERIALS AND METHODS: A mice tibia fracture model was constructed in this study. Mice in the control group and experimental group were sham-operated on the left tibia and were operated in the right tibia, respectively. The tibia bones of both groups were obtained at 4 d, 8 d, 12 d, 16 d, 20 d, and 24 d after the operation. Quantitative polymerase chain reaction (qPCR) was used to detect the expression of RBM5-AS1 in tibiae. After interfering with the expression of RBM5-AS1 in bone cells, Cell Counting Kit-8 (CCK-8) was used to detect cell proliferation ability, and flow cytometry was applied to detect apoptosis. Western blot was used to measure the protein expression of beta-catenin and RBM5 after down-regulating RBM5-AS1. Finally, beta-catenin was interfered in osteoblasts to explore the relationship between RBM5-AS1 and beta-catenin.

RESULTS: Compared with the control group, the expression of RBM5-AS1 in the experimental group was significantly increased on the 4 d, 8 d, 12 d, and 16 d after fracture surgery. However, no statistical difference was observed on the 20 d and 24 d between the two groups. After interfering with RBM5-AS1, the apoptosis of chondrocytes and osteoblasts was significantly increased in both mouse and human cells, while the expression of beta-catenin was strikingly decreased. Further up-regulation of beta-catenin could reduce the apoptosis of bone cells. The expression of RBM5, which was a natural antisense transcript of RBM5-AS1, was increased after down-regulating RBM5-AS1.

CONCLUSIONS: RBM5-AS1 can inhibit the apoptosis of bone cells by promoting the expression of beta-catenin and can be used as a biomarker for fracture healing.

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