Abstract: Objective: To investigate the effect of microRNA 34a-5p (miR-34a-5p) on the inflammation and differentiation of osteoblasts. Methods: MG63 was transfected with miR-34a-5p mimics to ensure a higher expression than general negative control (NC). Expression of miR-34a-5p was detected after MG63 was stimulated by different concentrations of lipopolysaccharide (LPS) from porphyromonas endodontalis (P.e). Transfected cells were stimulated by 20 mg/L P.e-LPS for 24 h, and expression of IL-6 was detected. Expressions of osteogenic differentiation markers and Notch1 were detected after osteogenic induction for 48 h. Results: Expression of miR-34a-5p in MG63 was down-regulated by P.e-LPS with different concentrations(P<0.05). MiR-34a-5p inhibited the expression of IL-6 significantly both with and without the stimulation of P.e-LPS(P<0.01). Osteogenic makers in MG63 were promoted by miR-34a-5p(P <0.05)and Notch1 was down-regulated(P<0.05). Conclusion: MiR-34a-5p inhibits the inflammation and promotes the differentiation of osteoblast, and Notch1 may serve as a target during the process.

Key words: MicroRNA 34a-5p, Osteoblast, Inflammation, Cell differentiation