Abstract: Objective:To explore the effects of miR-124a on the expression levels of tumor necrosis factor alpha (TNF-α)and interleukin-6(IL-6) and cell cycle in the macrophage J774.1 cells of the rheumatoid arthritis(RA) model mice, and to elucidate the mechanism of miR-124a in the pathogenesis of RA. Methods:The J774.1 cells in logarithmic growth phage were obtained and uniformly inoculated in the petri dish with 1×10⁶ mL^-1,and there were 3 multiple holes in each group;transfection was carried out when the fusion degree of the cells reached 60%.The cells were divided into blank control group(without any treatment), empty vector group(transfected with adenovirus negative fluid)and miR-124a overexpression group(transfected with miR-124a adenovirus vector).The expression levels of TNF-α and IL-6 in supernatant of the cells in three groups were detected by ELISA 48 h after transfection. RT-PCR was used to detect the relative expression levels of TNF-α and IL-6 mRNA in J774.1 cells 48 h after transfection and the changes of cell cycle were detected using flow cytometry. Results:The expression levels of TNF-α and IL-6 in supernatant of the cells in miR-124a overexpression group were lower than those in blank control group and empty vector group 48 h after transfection(P=0.038,P=0.042;P=0.043,P=0.044).The expression levels of TNF-α mRNA and IL-6 mRNA in miR-124a group were significantly lower than those in blank control group and empty vector group(P=0.001,P=0.002;P=0.001,P=0.003).The pecentage of cells in G₁ phase in miR-124a overexpression group was higher than those in blank control group and empty vector group(P<0.01);the percentages of cells in S phase and G₂ phase were lower than those in blank control group and empty vector group(P<0.01). Conclusion:MiR-124a can decrease the expression levels of inflammatory cytokines after transfecting the macrophages J774.1 cells,and inhibit the proliferation of cells.MiR-124a is a potential therapeutic target for the treatment of RA.

Key words: microRNA-124a, rheumatoid arthritis, adenovirus vector, J774.1 cells