miR-9-5p, miR-675-5p, and miR-138-5p reduced skeletal cell count and cell proliferation. (A) Representative photos of MC3T3-E1 cells transfected with miR-9-5p, miR-675-5p, and miR-138-5p; (B) Representative pictures of clonogenic assay with miR-9-5p, miR-675-5p, and miR-138-5p; (C) The clonogenic potential of MC3T3-E1 transfected with miR-9-5p, miR-675-5p, and miR-138-5p; (D) Fluorescence changes of MC3T3-E1 transfected with miR-9-5p and miR-675-5p, and ATDC5 transfected with miR-9-5p and miR-138-5p; (E) Determination of the cytotoxic activity of miR-9-5p on MC3T3-E1 cells; (F) Expression levels of PCNA in MC3T3-E1 cells upon transfection of miR-675-5p and miR-138-5p ** p < 0.01. n = 3/group.